INTRODUCTION — Bleeding from the vagina is a common event at all stages of pregnancy. The source is virtually never fetal. Bleeding usually results from disruption of blood vessels in the decidua (ie, pregnancy endometrium) or from discrete cervical or vaginal lesions. The clinician typically makes a provisional clinical diagnosis based upon the gestational age and the character of bleeding (eg, light or heavy, associated with pain or painless, intermittent or constant). Laboratory and imaging tests are then used to confirm or revise the initial diagnosis.
This topic will provide an overview of the etiology and evaluation of vaginal bleeding in pregnancy. Specific causes of bleeding and their management are discussed in detail separately. (Refer to individual topic reviews on each subject.)
URGENT CASES — The timing and setting for evaluation of bleeding depend upon the severity. If the patient is hemodynamically unstable, supportive measures and treatment should be rapidly initiated in an appropriate setting (eg, emergency department, labor and delivery unit). Although patients with severe blood loss (ie, requiring supportive care and rapid treatment) generally have orthostatic changes in blood pressure or pulse, occasionally, young pregnant patients can have massive bleeding without demonstrating hypotension or tachycardia. Careful assessment is important to avoid unnecessary delay in the management of such patients.
Hemoglobin/hematocrit, coagulation studies, and type and crossmatch should be obtained in all patients who are hemodynamically unstable (hypotension, tachycardia, orthostasis [systolic blood pressure decline of ≥20mmHg or diastolic blood pressure decline of ≥10 mmHg or heart rate increase of ≥30 beats/minute present after 3 minutes of standing, syncope).
The fetal heart rate should be checked and continuously monitored if emergency delivery would be considered because of an abnormal fetal heart rate. Such intervention is performed routinely in pregnancies ≥26 weeks of gestation, but more selectively at earlier gestational ages, particularly those at 22 to 23 weeks.
FIRST-TRIMESTER BLEEDING — Vaginal bleeding is common in the first trimester (up to 13+6 weeks [ie, 13 weeks plus 6 days of gestation]), occurring in 20 to 40 percent of pregnancies. Bleeding can be any combination of light or heavy, intermittent or constant, painless or painful.
Causes — The five major sources of nontraumatic bleeding in early pregnancy are:
●Ectopic pregnancy (See 'Ectopic pregnancy' below.)
●Early pregnancy loss (note that a variety of terms are used to describe early pregnancy loss (table 1)) (See 'Early pregnancy loss' below.)
●Threatened abortion (ie, vaginal bleeding with evidence of embryonic or fetal viability such as fetal cardiac activity) (See 'Threatened abortion' below.)
●Implantation of the pregnancy (See 'Physiologic or implantation bleeding' below.)
●Cervical, vaginal, or uterine pathology (eg, polyps, inflammation/infection, gestational trophoblastic disease) (See 'Vaginitis, trauma, tumor, warts, polyps, fibroids' below and 'Ectropion' below.)
Bleeding related to early pregnancy loss or threatened abortion is the most common nontraumatic cause of first-trimester bleeding (prevalence: 15 to 20 percent of pregnancies). Although bleeding may be heavy, almost all patients remain hemodynamically stable; only an approximate 1 percent of expectantly managed patients require blood transfusion [1].
Ectopic pregnancy is much less common (prevalence: 2 percent of pregnancies) but is the most serious etiology of first-trimester bleeding. Rupture of an ectopic pregnancy is a potentially life-threatening complication; therefore, this diagnosis must be excluded in every pregnant patient with bleeding.
Evaluation — The goal of the evaluation is to make a definitive diagnosis when possible and exclude the presence of serious pathology in the remaining cases (algorithm 1). The exact etiology of vaginal bleeding in the first trimester often cannot be determined.
Ectopic pregnancy is particularly important to exclude since it can be life-threatening. Thus, the first step in evaluation is to determine whether the patient has had an ultrasound examination and the results of this examination. Prior documentation that the pregnancy is in the normal intrauterine location immediately narrows the differential diagnosis, although the possibility that the prior ultrasound may have missed a heterotopic pregnancy (ie, one intrauterine and one extrauterine pregnancy) or a cornual (interstitial) ectopic pregnancy should always be considered. If in doubt, consider repeating the examination. (See "Ectopic pregnancy: Clinical manifestations and diagnosis", section on 'Heterotopic pregnancy' and "Ectopic pregnancy: Clinical manifestations and diagnosis", section on 'Interstitial pregnancy'.)
History — The extent of bleeding should be determined: Is the patient passing blood clots or is the blood soaking through her clothes? Do they feel lightheaded? Do they have significant pelvic pain or cramping? Have they passed any tissue? If the patient answers yes to any of these questions, then ectopic pregnancy and early pregnancy loss are much more likely diagnoses than implantation bleeding, threatened abortion, or cervicovaginal disorders (eg, polyps, cervicitis, cancer). On the other hand, it is important to remember that the presence of only light, intermittent, painless bleeding does not exclude the possibility of a life-threatening underlying disorder, such as ectopic pregnancy.
What is the patient's medical history? A past history of ectopic pregnancy or risk factors for ectopic pregnancy (table 2)increase the probability of this disorder. (See "Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites".)
A history of two or more consecutive early pregnancy losses or a condition associated with early pregnancy loss (eg, chromosomal translocation in either parent, maternal antiphospholipid syndrome, uterine anomaly) increases the likelihood that bleeding is related to impending pregnancy loss. (See "Pregnancy loss (miscarriage): Terminology, risk factors, and etiology".)
Use of assisted reproductive technologies to achieve conception increases the risk of heterotopic pregnancy. (See "Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites", section on 'Heterotopic pregnancy'.)
Physical examination — Any tissue the patient has passed should be examined. Patients may mistake blood clot for the products of conception. If the tissue represents a partial or complete early pregnancy loss, the fetal membranes, fronds indicative of placental villi, or an intact fetus should be visible upon careful examination. Visualization of villi can be facilitated by floating the products of conception in water (picture 1A-B).
An abdominal examination should be performed before the internal examination. It is best to begin by examining the quadrant where the patient is experiencing the least pain. Gentle percussion is preferable to deep palpation since it causes less pain and guarding. Midline pain is more consistent with early pregnancy loss, while lateral pain is more consistent with ectopic pregnancy. Nongynecologic causes of pain should also be considered. (See "Approach to acute abdominal/pelvic pain in pregnant and postpartum patients".)
If the pregnancy is at or beyond 10 to 12 weeks of gestation, a handheld Doppler ultrasound device can be used to check the fetal heartbeat. The fetal heart rate usually can be easily distinguished from the maternal heart rate since the fetal heart rate is typically in the range of 110 to 160 beats per minute; however, the difference in maternal and fetal heart rates can be minimal if the mother has tachycardia [2]. Doppler confirmation of fetal cardiac activity is reassuring, as it indicates bleeding is not related to fetal demise and unlikely to be related to an ectopic pregnancy. On the other hand, loss of a previously detected fetal heart beat should raise suspicion that fetal demise has occurred. However, inability to detect fetal heart motion by Doppler, particularly in the first trimester, may merely reflect the difficulty in blindly finding the location of the tiny fetal heart.
After the abdominal examination, the patient is placed in the lithotomy position and an internal (ie, pelvic) examination is performed. The clinician should determine whether uterine size is appropriate for the estimated gestational age. The size-gestational age correlation is learned by experience and is often described in terms of fruit (eg, 6- to 8-week size = small pear, 8- to 10-week size = orange, 10- to 12-week size = grapefruit). The uterus remains a pelvic organ until approximately 12 weeks of gestation, when it becomes sufficiently large to palpate transabdominally just above the symphysis pubis. The normal uterus is nontender, smooth, and firm.
A speculum is then inserted into the vagina to assess the volume and source of bleeding. If blood clots, products of conception, or both are present, they can be removed with gauze sponges on a sponge forceps. This tissue is examined as described above and, by convention, sent for pathologic examination to confirm the presence of products of conception and to exclude gestational trophoblastic disease. The utility of routine histopathological examination is questionable, as it rarely suggests the underlying cause of the pregnancy failure or establishes a diagnosis of gestational trophoblastic disease [3]. However, pathologists can sometimes diagnose entities that are the probable cause of the loss or associated with recurrent loss. These include massive chronic intervillositis, massive intervillous fibrin deposition, maternal vasculitis, findings suggestive of some fetal chromosomal anomalies (eg, triploidy, some trisomies), and septic abortion.
Speculum examination may reveal a source of bleeding unrelated to pregnancy; in such cases, further evaluation depends upon the nature of the abnormality:
●Vaginal laceration (see "Evaluation and management of female lower genital tract trauma")
●Vaginal neoplasm (see "Vaginal cancer")
●Vaginal warts (see "Condylomata acuminata (anogenital warts) in adults: Epidemiology, pathogenesis, clinical features, and diagnosis")
●Vaginal discharge (see "Vaginal discharge (vaginitis): Initial evaluation")
●Cervical polyps, fibroids, ectropion (see "Benign cervical lesions and congenital anomalies of the cervix")
●Mucopurulent cervical discharge or friability at the cervical os (see "Acute cervicitis")
●Cervical neoplasm (see "Invasive cervical cancer: Epidemiology, risk factors, clinical manifestations, and diagnosis")
Visualization of the internal cervical os is possible in some cases and helps to distinguish between a threatened and a true early pregnancy loss. Direct visualization of the gestational sac in a dilated internal cervical os is generally sufficient to conclude that early pregnancy loss is inevitable. The internal cervical os will usually also be open with incomplete or recently completed passage of an early pregnancy loss. An open internal cervical os will admit a small instrument, such as a cotton-tipped swab. Ultrasound can provide additional information in these cases, such as whether there are retained products of conception or the unexpected presence of a twin pregnancy with a second viable gestational sac. Therefore, it is prudent to not suggest to patients that the pregnancy has been lost until ultrasound findings are available and the diagnosis is confirmed.
A closed internal cervical os is most consistent with a threatened abortion, but not diagnostic. If the internal cervical os appears closed and there are no obvious bleeding lesions, the speculum is removed and a bimanual pelvic examination is performed. With an ectopic pregnancy, findings on pelvic examination may include adnexal, cervical motion, or abdominal tenderness; an adnexal mass; and mild uterine enlargement. However, the physical examination is often unremarkable in a patient with a small, unruptured ectopic pregnancy. (See "Ectopic pregnancy: Clinical manifestations and diagnosis".)
In contrast to the internal os, an open external cervical os is usually not helpful diagnostically because it is a normal finding, especially in parous patients.
Uterine size larger than expected for dates suggests a multiple gestation, possibly with demise of one of the multiples; gestational trophoblastic disease (eg, molar pregnancy); or other uterine pathology (fibroids often cause irregular uterine enlargement). (See "Twin pregnancy: Overview" and "Hydatidiform mole: Epidemiology, clinical features, and diagnosis" and "Uterine fibroids (leiomyomas): Epidemiology, clinical features, diagnosis, and natural history".)
One review of data from observational studies concluded that ultrasound examination and human chorionic gonadotropin (hCG) concentration (both discussed below) could replace pelvic examination in the initial evaluation of patients with early pregnancy bleeding [4]. However, some diagnoses will be missed with this approach (eg, bleeding from cervical or vaginal lesions), this combination of tests may not distinguish between a complete early pregnancy loss and an ectopic pregnancy (both will have an empty uterus and positive hCG), and the additional cost of these tests can be avoided in some patients. For example, in bleeding patients in whom sonography has previously confirmed a viable singleton intrauterine pregnancy, another examination is not necessary to exclude ectopic pregnancy or to confirm fetal viability if fetal heart motion can be detected by a handheld Doppler device. Additionally, there is no value in checking the hCG concentration once the presence of an intrauterine pregnancy has been established sonographically (eg, presence of an intrauterine gestational sac containing a yolk sac or embryo/fetus).
Transvaginal ultrasonography — Transvaginal ultrasonography is the cornerstone of the evaluation of bleeding in early pregnancy. It is most useful in bleeding patients with a positive pregnancy test in whom an intrauterine pregnancy has not been previously confirmed by imaging studies. In these patients, ultrasound examination is performed to determine whether the pregnancy is intrauterine or extrauterine (ectopic) and, if intrauterine, whether the pregnancy is viable (fetal cardiac activity present) or nonviable. The possibility of heterotopic pregnancy should always be considered. (See "Ectopic pregnancy: Clinical manifestations and diagnosis", section on 'Transvaginal ultrasound'.)
It is important to note that the absence of an intrauterine gestational sac is highly suggestive of ectopic pregnancy if more than 5.5 to 6 weeks have elapsed since the first day of the patient's last menstrual period. At earlier gestational ages, however, an intrauterine pregnancy may be present, but not yet identifiable, by ultrasound (table 3). In these cases, sonographic findings are correlated with hCG levels. The use of sonography and hCG in the differential diagnosis of intrauterine versus extrauterine pregnancy and viable versus nonviable intrauterine pregnancy is described briefly below (see 'Laboratory tests' below) and in detail separately. (See "Pregnancy loss (miscarriage): Terminology, risk factors, and etiology" and "Ectopic pregnancy: Clinical manifestations and diagnosis".)
Rarely, ultrasound examination reveals unusual causes of vaginal bleeding, such as gestational trophoblastic disease or loss of one fetus from a multiple gestation. (See "Hydatidiform mole: Epidemiology, clinical features, and diagnosis" and "Twin pregnancy: Overview", section on 'Vanishing twins'.)
In bleeding patients in whom sonography has previously confirmed a viable singleton intrauterine pregnancy, another examination is not necessary to confirm fetal viability if fetal heart motion can be detected by a handheld Doppler device.
Other imaging tests — If transvaginal ultrasound is not readily available to assess the uterus, transabdominal ultrasound is useful. Transvaginal ultrasound allows for earlier and more reliable detection of an intrauterine or ectopic pregnancy and is more sensitive for detecting embryonic cardiac activity at very early gestational ages compared with transabdominal ultrasound, but the latter is useful for assessing free fluid in the abdomen (eg, bleeding from an ectopic pregnancy) and abnormalities beyond the field of view of a high-frequency vaginal probe.
Magnetic resonance imaging (MRI) is rarely indicated but may be used as a second-line imaging modality for further evaluation of limited and nondiagnostic ultrasound, an unusual ectopic pregnancy, gestational trophoblastic disease, and differentiating causes of severe pelvic pain and adnexal masses.
Computed tomography (CT) may be useful in pregnant patients with trauma or acute nongynecologic pain, for staging of malignancy, or if magnetic resonance imaging is not possible. It is not the preferred modality since it involves use of ionizing radiation, but it can be performed safely and should be used when other imaging modalities do not provide adequate diagnostic information. (See "Diagnostic imaging in pregnant and nursing patients".)
Laboratory tests — There is no role for monitoring hCG concentration once the presence of an intrauterine pregnancy has been established sonographically. Serial measurements of hCG are helpful during the first six weeks of pregnancy if ultrasonography is nondiagnostic (ie, the location and viability of the pregnancy are not revealed), as shown in the algorithm (algorithm 2). The pattern of hCG change in normal and abnormal pregnancies and its correlation with ultrasound findings is complicated and discussed in detail separately. (See "Ectopic pregnancy: Clinical manifestations and diagnosis".) Other hormone assays (eg, progesterone, estrogen, inhibin A, pregnancy-associated protein-A [PAPP-A]) are less useful than hCG.
In hemodynamically stable patients, a baseline hemoglobin/hematocrit measurement can be useful in those with heavy vaginal bleeding, particularly if persistent, and in those with ruptured ectopic pregnancy.
Differential diagnosis and management — The information gleaned from the evaluation described above is used to determine a diagnosis and plan of management. Patients with significant first-trimester vaginal bleeding (ie, more than spotting) should have a red blood cell antibody screen checked. Those who are RhD-negative are generally given anti-D immune globulin to protect against RhD alloimmunization, unless the vaginal bleeding is clearly due to a nonplacental, nonfetal source, such as a vaginal laceration. Some guidelines do not administer anti-D immune globulin to patients with threatened abortion or complete or incomplete pregnancy loss <12 weeks of gestation [5]. (See "RhD alloimmunization: Prevention in pregnant and postpartum patients".)
Ectopic pregnancy — All patients with early pregnancy bleeding and pain are assumed to have ectopic pregnancy until this diagnosis has been excluded by laboratory and imaging studies. Patients with a history of ectopic pregnancy or other risk factors for the disorder (table 2) are at highest risk, but many patients with ectopic pregnancy have no risk factors.
The discriminatory zone is the serum hCG level above which a gestational sac should be visualized by transvaginal ultrasound if an intrauterine pregnancy is present. The discriminatory zone varies somewhat by laboratory and institution; some institutions set the discriminatory zone at 2000 and others use 3510 milli-international units/mL (for transabdominal ultrasound, the discriminatory zone is higher: approximately 6500 milli-international units/mL). Setting the discriminatory zone at 3510 international units/L minimizes the risk of interfering with a viable singleton intrauterine pregnancy, if present, although it increases the risk of delaying diagnosis of an ectopic pregnancy. The absence of a sonographically identifiable intrauterine pregnancy when the hCG concentration is greater than the discriminatory threshold is not absolute proof of ectopic pregnancy because of the possibility of a very early multiple gestation (hCG levels are higher in multiple gestations).
Diagnosis of intrauterine (viable or nonviable) versus extrauterine pregnancy at hCG concentrations below the discriminatory zone is complicated and discussed in detail separately. Other findings that should be considered when making a diagnosis are whether an adnexal mass is present and the likely etiology of the mass (ectopic pregnancy versus corpus luteum cyst) and whether the patient is hemodynamically unstable or has a tender abdomen, which suggests a ruptured ectopic pregnancy or corpus luteum cyst. (See "Ectopic pregnancy: Clinical manifestations and diagnosis" and "Ultrasonography of pregnancy of unknown location".)
Management of ectopic pregnancy is generally medical (methotrexate therapy) or surgical. (See "Ectopic pregnancy: Methotrexate therapy" and "Ectopic pregnancy: Surgical treatment".) Expectant management can be dangerous for the patient, but may be possible in rare cases. (See "Ectopic pregnancy: Expectant management".)
Even if an intrauterine pregnancy is diagnosed, the possibility of heterotopic pregnancy should be kept in mind, even though rare (1 in 30,000 pregnancies). This is particularly important in patients who conceived via assisted reproductive technology (ART) since they are at increased risk of this pregnancy complication (1.5 per 1000 ART pregnancies). (See "Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites", section on 'Heterotopic pregnancy'.)
Other abnormally implanted pregnancies
●Cervical pregnancy is a rare form of ectopic pregnancy in which the pregnancy implants in the lining of the endocervical canal. Vaginal bleeding is the most common symptom and is often painless and profuse, resulting in hemodynamic instability. It may be misdiagnosed as an incomplete early pregnancy loss. (See "Cervical pregnancy".)
●Cesarean scar pregnancy occurs from implantation of the pregnancy into either a wedge defect in the lower uterine segment at the site of the hysterotomy for a previous cesarean birth or a microscopic fistula within the hysterotomy scar. As the pregnancy enlarges, vaginal bleeding with or without pain may occur. (See "Cesarean scar pregnancy".)
Early pregnancy loss — A variety of terms (table 1) are used to describe nonviable pregnancies. (See "Pregnancy loss (miscarriage): Terminology, risk factors, and etiology".)
Threatened abortion — Vaginal bleeding in the presence of a closed cervix and sonographic visualization of an intrauterine pregnancy with detectable fetal cardiac activity is diagnostic of threatened early pregnancy loss. The term "threatened" is used to describe these cases because early pregnancy loss does not always follow vaginal bleeding, even after repeated episodes or large amounts of bleeding. In fact, 90 to 96 percent of pregnancies with both fetal cardiac activity and vaginal bleeding at 7 to 11 weeks of gestation are not lost; the 96 percent ongoing pregnancy rate is associated with bleeding at the later end of this gestational age range [6,7].
Bleeding in these cases is likely due to disruption of decidual vessels at the maternal-fetal interface. These separations generally cannot be visualized by ultrasound, but sometimes appear as a subchorionic hematoma. Subchorionic hemorrhage or hematoma is associated with increased risk of pregnancy loss, particularly when it amounts to 25 percent or more of the volume of the gestational sac (image 1A-B) [8]. In a meta-analysis of seven comparative studies, pregnant individuals with subchorionic hematoma had double the odds of pregnancy loss compared with those without (18 versus 9 percent, OR 2.18, 95% CI 1.29-3.68) [9]. Management is expectant; available evidence does not support a benefit of progesterone supplementation in patients with threatened abortion and zero or one previous pregnancy loss [10].
The role of progesterone supplementation in recurrent pregnancy loss (two or more failed clinical pregnancies or three consecutive pregnancy losses), after removal of the corpus luteum prior to eight weeks of gestation, and for luteal support on the day of oocyte retrieval or at the time of embryo transfer in pregnancies conceived in vitro are reviewed separately.
●(See "Recurrent pregnancy loss: Definition and etiology" and "Recurrent pregnancy loss: Evaluation" and "Recurrent pregnancy loss: Management".)
●(See "Adnexal mass in pregnancy", section on 'Management of corpus luteum'.)
●(See "In vitro fertilization: Procedure", section on 'Luteal phase support'.)
Complete pregnancy loss — When a pregnancy loss occurs before 12 weeks of gestation, it is common for the entire contents of the uterus to be expelled, thereby resulting in complete pregnancy loss. If this has occurred, the uterus is small on physical examination and well contracted with an open or closed internal cervical os, scant vaginal bleeding, and only mild cramping. Ultrasound will reveal an empty uterus and no extrauterine gestation.
A complete early pregnancy loss can be distinguished from an ectopic pregnancy by examining the tissue that was passed to confirm products of conception, by demonstrating falling rather than rising or plateaued hCG levels, and by patient description of diminishing bleeding and pain. No further intervention is needed for complete early pregnancy loss if chorionic villi are identified by pathologic examination of the products of conception. However, if no villi are identified or no specimens are available for pathologic examination, then serum hCG levels should be followed serially until the level is undetectable.
Incomplete pregnancy loss — When an early pregnancy loss is inevitable, the internal os of the cervix is dilated and/or effaced, vaginal bleeding is increasing, and painful uterine cramps/contractions are present. The gestational tissue often can be felt or seen at the internal cervical os; passage of this tissue typically occurs within a short time. Management may be expectant, or a medical or surgical intervention to complete the process can be undertaken. (See "Pregnancy loss (miscarriage): Description of management techniques" and "Pregnancy loss (miscarriage): Counseling and comparison of treatment options and discussion of related care".)
At a more advanced stage, the membranes may rupture and the fetus may be passed, but significant amounts of placental tissue can be retained, resulting in an incomplete early pregnancy loss. This is most common in the late first trimester and early second trimester. On examination, the internal cervical os is open, gestational tissue may be observed in the cervical canal, and the uterine size is smaller than expected for gestational age, but not well contracted. The amount of bleeding varies, but can be sufficiently severe to cause hypovolemic shock. Painful cramps/contractions are often present. Ultrasound reveals tissue in the uterus. Medical or surgical evacuation is generally performed. (See "Pregnancy loss (miscarriage): Description of management techniques" and "Pregnancy loss (miscarriage): Counseling and comparison of treatment options and discussion of related care".)
Missed abortion — A missed abortion (also called a delayed early pregnancy loss) refers to in-utero death of the embryo or fetus prior to the 20th week of gestation, with retention of the pregnancy for a prolonged period of time. (An embryo is considered a fetus beginning in the 11th week of gestation, which is the 9th week of development after fertilization of the egg).
Patients may notice that symptoms associated with early pregnancy (eg, nausea, breast tenderness) have abated and they do not "feel pregnant" anymore. Vaginal bleeding may occur. The internal cervical os usually remains closed. Ultrasound reveals an intrauterine gestational sac with or without an embryonic/fetal pole, but no embryonic/fetal cardiac activity. Management may be expectant or a medical or surgical intervention to complete process can be undertaken. (See "Pregnancy loss (miscarriage): Description of management techniques" and "Pregnancy loss (miscarriage): Counseling and comparison of treatment options and discussion of related care".)
Vanishing twin — The term "vanishing twin" has been used to describe a singleton pregnancy which results from very early loss of one member of a multiple gestation. Vanishing twins are often the product of assisted reproduction techniques and can be associated with vaginal bleeding [11]. (See "Assisted reproductive technology: Pregnancy and maternal outcomes", section on 'Early pregnancy loss' and "Twin pregnancy: Overview", section on 'Vanishing twins'.)
Vaginitis, trauma, tumor, warts, polyps, fibroids — These conditions are diagnosed by visual inspection, with ancillary tests as indicated (eg, wet mount and pH of vaginal discharge, cervical cytology and/or biopsy of mass lesions, ultrasound examination of uterus to detect neoplastic lesions). Even if a lesion appears to be the source bleeding on pelvic examination, it is prudent to always consider the possibility of ectopic pregnancy in patients with first-trimester bleeding, especially if associated with pain. (See 'Ectopic pregnancy' above.)
Management of bleeding related to these conditions depends upon the specific condition. (Refer to individual topic reviews on each disorder).
Ectropion — Cervical ectropion (columnar epithelium exposed to the vaginal milieu by eversion of the endocervix) is a common and normal finding in pregnancy. The exposed columnar epithelium is prone to light bleeding when touched, such as during vaginal intercourse, insertion of a speculum, bimanual examination, or when a cervical specimen is obtained for cytology or culture. Therapy is unnecessary. (See "Benign cervical lesions and congenital anomalies of the cervix", section on 'Ectropion'.)
Physiologic or implantation bleeding — This is a diagnosis of exclusion. It is characterized by a small amount of spotting or bleeding approximately 10 to 14 days after fertilization (at the time of the missed menstrual period), and is presumed to be related to implantation of the fertilized egg in the decidua (ie, lining of the uterus) [12], although this hypothesis has been questioned [13]. No intervention is indicated.
Prognosis — Studies consistently show an association between first-trimester bleeding and adverse outcome later in pregnancy (eg, early pregnancy loss, preterm birth, preterm prelabor rupture of membranes, fetal growth restriction) [13-26]. The prognosis is best when bleeding is light and limited to early pregnancy (ie, less than 6 weeks of gestation) [13,22] and worsens when bleeding is heavy or extends into the second trimester [17-21].
There are no effective interventions, but patients can be reassured of the low likelihood of adverse outcome. In particular, bed rest is unnecessary and will not improve outcome. (See "Preterm birth: Risk factors, interventions for risk reduction, and maternal prognosis", section on 'Vaginal bleeding in early pregnancy'.)
The relationship between early pregnancy bleeding and pregnancy outcome is illustrated by the following examples:
●In a series of 550 patients followed prospectively from the time of their positive pregnancy test, 117 (21 percent) had bleeding prior to 20 weeks of gestation and 67 miscarried (12 percent, or approximately one-half of those with bleeding) [27]. Fourteen of 18 pregnancies with heavy bleeding (eg, clots) and moderate pain miscarried (78 percent).
●In a prospective series in which all subjects (n >16,500) had a viable pregnancy at enrollment at 10 to 14 weeks, the frequency of preterm birth in those with no, light, or heavy first-trimester bleeding was approximately 6, 9, and 14 percent, respectively, and the frequency of spontaneous loss before 24 weeks of gestation was 0.4, 1, and 2 percent, respectively [17]. Because these patients were enrolled late in the first trimester and with sonographically confirmed fetal viability, those with very early bleeding and early pregnancy loss had already been excluded.
●In a third series, vaginal bleeding occurring in more than one trimester was associated with a greater than sevenfold increased risk of preterm prelabor rupture of membranes (odds ratio [OR] 7.4, 95% CI 2.2-25.6) [21].
●A retrospective registry-based study including over one million pregnant patients found that, compared with patients without bleeding, first-trimester bleeding increased the risk of preterm birth at 28 to 31 weeks (0.9 versus 0.3 percent, OR 2.98, 95% CI 2.50-3.54) and at 32 to 36 weeks (6.1 versus 3.6 percent, OR 1.65, 95% CI 1.57-1.77), and increased the risk of placental abruption (1.4 versus 1.0 percent, OR 1.48, 95% CI 1.30-1.68) [23]. In addition, patients with first-trimester bleeding in their first pregnancy were more likely to bleed in their second pregnancy than those with no bleeding in their first pregnancy (8.2 versus 2.2 percent, OR 4.05, 95% CI 3.78-4.34).
SECOND- AND THIRD-TRIMESTER BLEEDING
Overview — Vaginal bleeding is less common in the second trimester (14+0 to 27+6 weeks) and third trimester (28+0 weeks to birth). The major causes of bleeding at these times are:
●Bloody show associated with labor (by definition, labor occurs after 20 weeks of gestation) or, less commonly, cervical insufficiency
●Pregnancy loss (defined here as a loss between 14 and 20 weeks of gestation)
●Placenta previa
●Placental abruption
●Uterine rupture (rare)
●Vasa previa (rare)
Cervical, vaginal, or uterine pathology (eg, polyps, inflammation/infection, trophoblastic disease) and nontubal ectopic pregnancy are other etiologies.
Prior to 20 weeks of gestation
Evaluation — The evaluation of pregnant patients with vaginal bleeding prior to 20 weeks is similar to that in the first trimester (see 'Evaluation' above); however, ectopic pregnancy is less of a concern because over 95 percent of ectopic pregnancies occur in the fallopian tube and virtually all tubal ectopic pregnancies will have been diagnosed by this time. Although abdominal, heterotopic, cervical, cornual (also called interstitial), and cesarean scar pregnancies often present at more advanced gestations than tubal ectopics, these types of pregnancy are rare.
The first step in the evaluation is to determine the extent of bleeding and whether bleeding is accompanied by pain. The presence of only light, intermittent, painless bleeding suggests bloody show from cervical insufficiency, a small marginal placental separation, or a cervical or vaginal lesion (eg, polyp, infection, cancer). Heavier bleeding, particularly when associated with pain, is more consistent with impending pregnancy loss or a larger placental separation (ie, abruption). A baseline hemoglobin/hematocrit measurement can be useful in patients with heavy vaginal bleeding, particularly if persistent.
As discussed above, loss of a previously detected fetal heart beat should raise suspicion that fetal demise has occurred, but inability to detect the fetal heart by Doppler ultrasound is subject to clinician error and should always be confirmed by ultrasound examination. On the other hand, Doppler confirmation of fetal cardiac activity is reliable and reassuring, unless maternal tachycardia is present and misinterpreted as the fetal heart rate (simultaneously checking the maternal pulse can exclude this possibility).
An abdominal examination is performed to assess for pain or other abnormalities and uterine size. At 16 weeks of gestation, the uterine fundus is palpable approximately midway between the symphysis pubis and umbilicus, while at 20 to 22 weeks, it is palpable at approximately the level of the umbilicus.
After the abdominal examination, the patient is placed in the lithotomy position. The external genitalia are examined and then a speculum is inserted into the vagina. Physical examination may reveal a nonpregnancy-related source of bleeding, such as cervical ectropion, an abnormal growth, a laceration, or sanguineous-purulent discharge.
Direct visualization of a dilated internal os or fetal membranes may be sufficient to diagnose impending pregnancy loss if contractions are present, or cervical insufficiency in the absence of contractions.
Transvaginal ultrasonography is the cornerstone in the evaluation of bleeding in the second trimester. The primary goals are to determine whether the placenta is covering the cervical os (placenta previa), whether there is evidence of decidual hemorrhage causing placental separation (ie, placental abruption), and whether the cervix shows signs suggestive of cervical insufficiency (short length, dilated internal os, prolapsed fetal membranes). (See "Short cervix before 24 weeks: Screening and management in singleton pregnancies" and "Cervical insufficiency".)
Differential diagnosis
Early pregnancy loss — (See 'Threatened abortion' above and 'Early pregnancy loss' above.)
Cervical insufficiency — The diagnosis of cervical insufficiency is clinical; the classic presentation is cervical dilation and effacement in the second trimester with fetal membranes visible at or beyond the external os in the absence of contractions. Symptoms include one or more of the following: vaginal fullness or pressure; vaginal spotting or bleeding; an increased volume of watery, mucus or brown vaginal discharge; and vague discomfort in the lower abdomen or back. In asymptomatic patients, the sonographic finding of a short cervix (≤25 mm before 24 weeks) in a patient with a previous preterm birth supports the diagnosis. (See "Cervical insufficiency" and "Short cervix before 24 weeks: Screening and management in singleton pregnancies".)
Cervical, vaginal, or uterine pathology — (See 'Vaginitis, trauma, tumor, warts, polyps, fibroids' above.)
Ectopic pregnancy — Ectopic pregnancy is rare at this gestational age. When an abnormal pregnancy is diagnosed after the first trimester, the location is likely to be nontubal (abdominal, cervical, cesarean scar, or cornual [interstitial]) or heterotopic (ie, coexistent intrauterine and extrauterine pregnancies). (See "Abdominal pregnancy" and "Cervical pregnancy" and "Cesarean scar pregnancy" and "Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites", section on 'Interstitial or cornual pregnancy' and "Ectopic pregnancy: Clinical manifestations and diagnosis", section on 'Heterotopic pregnancy'.)
Placental abruption — Hemorrhage into the decidua basalis can cause bleeding, cramping, and placental separation. The diagnosis is one of exclusion since placental separation usually cannot be visualized on ultrasound examination. The presence of a subchorionic hematoma or placenta that covers the internal cervical os supports the diagnosis. (See "Acute placental abruption: Pathophysiology, clinical features, diagnosis, and consequences".)
Bleeding after 20 weeks of gestation — The term antepartum bleeding typically refers to vaginal bleeding after 20 weeks of gestation that is unrelated to labor and delivery. Antepartum bleeding complicates 4 to 5 percent of pregnancies. The major causes are:
●Placenta previa (20 percent)
●Placental abruption (30 percent)
●Uterine rupture (rare)
●Vasa previa (rare)
In the remaining 50 percent of cases, the etiology of the antepartum bleeding cannot be determined with certainty. These cases are frequently attributed to marginal separation of the placenta.
Evaluation — In contrast to bleeding in the first half of pregnancy, digital examination of the cervix should be avoided in patients presenting with bleeding in the second half of pregnancy until placenta previa has been excluded by ultrasound examination. Digital examination of a placenta previa can cause immediate, severe hemorrhage.
Hemoglobin/hematocrit and coagulation studies should be obtained in all patients who are hemodynamically unstable (hypotension, tachycardia, orthostasis, syncope). A baseline hemoglobin/hematocrit measurement can be useful in patients with heavy vaginal bleeding, particularly if persistent, and in those with concealed retroplacental hemorrhage.
Differential diagnosis
Bloody show — "Bloody show" is the term used to describe the small amount of blood with mucus discharge that may precede the onset of labor by as much as 72 hours.
Placenta previa — Placenta previa should be suspected in any patient who presents with vaginal bleeding in the second half of pregnancy. Classically, the absence of abdominal pain and uterine contractions was considered the clinical feature that distinguished between placenta previa and abruption, which is the other major cause of vaginal bleeding at this time. However, some patients with placenta previa have uterine contractions in addition to bleeding; thus, the diagnosis of placenta previa must be determined by sonographic examination. (See "Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality".)
Placental abruption — Placental abruption (abruptio placentae) refers to premature separation of a normally implanted placenta prior to birth of the infant. The most common risk factors include prior abruption, trauma, smoking, cocaine use, hypertension, and preterm prelabor rupture of membranes.
Clinically, abruption typically presents with vaginal bleeding (80 percent), uterine tenderness (70 percent), and uterine contractions (35 percent), with or without abnormalities of the fetal heart rate pattern. Uterine tenderness is caused by extravasation of blood into the myometrium (called a Couvelaire uterus, an enlarged bluish-purple uterus due to the extravasation of blood through the myometrium to the serosa). In severe cases, blood can even penetrate to the peritoneal cavity. The amount of vaginal bleeding may not be a reliable indicator of the severity of the hemorrhage since bleeding may be concealed (retained in the uterine cavity). Ultrasound may show placental separation, but this is uncommon (only 2 percent of abruptions can be visualized on ultrasound). The major purpose of ultrasound examination is to exclude placenta previa, not to diagnose or exclude abruption. Abruption may be mild to severe (life-threatening to mother or fetus) and may be acute or chronic. (See "Acute placental abruption: Pathophysiology, clinical features, diagnosis, and consequences".)
The possibility of abruption should always be considered in patients who are being evaluated for trauma (eg, motor vehicle crash, fall, domestic violence). (See "Initial evaluation and management of major trauma in pregnancy", section on 'Placental abruption'.)
Cervical, vaginal, or uterine pathology — (See 'Vaginitis, trauma, tumor, warts, polyps, fibroids' above and 'Ectropion' above.)
Uterine rupture — Uterine rupture is a rare cause of vaginal bleeding. In patients with vaginal bleeding and a previous cesarean birth or transmyometrial surgery, the possibility of uterine rupture should always be considered. It usually occurs during labor or as a result of abdominal trauma, but can rarely occur without an obvious precipitating cause. Abdominal pain, fetal heart rate abnormalities, and hemodynamic instability due to intra-abdominal bleeding are likely and indicate an obstetric emergency. (See "Uterine rupture: After previous cesarean birth" and "Uterine rupture: Unscarred uterus".)
Vasa previa — In vasa previa, fetal blood vessels are present in the membranes covering the internal cervical os. The membranous vessels may be associated with a velamentous umbilical cord or they may connect the lobes of a bilobed placenta or the placenta and a succenturiate lobe. Rupture of the vasa previa is an obstetric emergency and may lead to fetal death from exsanguination. Risk factors for vasa previa include multiple gestation and in vitro fertilization (See "Velamentous umbilical cord insertion and vasa previa".)
Prognosis — As with first-trimester bleeding, episodes of second- and third-trimester bleeding are also associated with adverse pregnancy outcome, primarily preterm birth. (See "Preterm birth: Risk factors, interventions for risk reduction, and maternal prognosis", section on 'Vaginal bleeding in early pregnancy'.)
The risk of adverse outcome appears to depend on the degree of bleeding (worse outcome with heavier bleeding) and the cause (worse outcome with bleeding from non-previa source) [28]. Antepartum bleeding of unknown origin in the second half of pregnancy has been reported to increase the risk of preterm birth two- to threefold [29,30].
Management — The management of pregnant patients with vaginal bleeding in the second and third trimesters depends on numerous factors, including the gestational age, the cause of bleeding, the severity of bleeding, and fetal status. Management is discussed in the individual topic reviews on the specific causes of vaginal bleeding in this gestational age range.
RARE CAUSES OF ANTEPARTUM BLEEDING
Choriocarcinoma — A history of a molar pregnancy is the most important risk factor for choriocarcinoma, but it can occur after any type of antecedent pregnancy (spontaneous or induced abortion, preterm or term birth) and rarely occurs coexistent with a normal intrauterine pregnancy. Antepartum vaginal bleeding is the most common presenting symptom and can occur in any trimester. It may result from vaginal metastases or from the intrauterine tumor. Other symptoms that have been reported include respiratory symptoms from lung metastases, neurologic symptoms from brain metastases, and acute abdominal pain from bleeding intraabdominal metastases [31,32]. The diagnosis should be considered after other more common causes of antepartum bleeding have been excluded, especially in patients with respiratory or neurologic symptoms. (See "Gestational trophoblastic neoplasia: Epidemiology, clinical features, diagnosis, staging, and risk stratification".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Bleeding in early pregnancy (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Overview – Bleeding from the vagina is a common event at all stages of pregnancy; the source is virtually never fetal. A provisional clinical diagnosis of the cause is based on the patient's gestational age and character of the bleeding (eg, light or heavy, associated with pain or painless, intermittent or constant). Laboratory and imaging tests are then used to confirm or revise the initial diagnosis. (See 'Introduction' above.)
●Early pregnancy
•Causes – The five major causes of bleeding in early pregnancy are (see 'Causes' above):
-Ectopic pregnancy
-Early pregnancy loss
-Threatened or impending abortion
-Physiologic (ie, related to implantation of the pregnancy)
-Cervical, vaginal, or uterine pathology (eg, polyps, inflammation/infection, gestational trophoblastic disease)
•Diagnostic evaluation – Transvaginal ultrasonography is the cornerstone of the evaluation of bleeding in early pregnancy (algorithm 1). Most diagnoses can be made or excluded with this modality. (See 'Evaluation' above.)
•Exclude ectopic pregnancy – An important goal in the evaluation of patients with bleeding in early pregnancy is to exclude the possibility of ectopic pregnancy, since ruptured ectopic pregnancy can result in severe hemorrhage and death (algorithm 2). (See 'Ectopic pregnancy' above.)
●Second and third trimesters
•Causes – The major causes of bleeding in the second and third trimesters are (see 'Overview' above):
-Bloody show associated with labor (by definition, labor occurs after 20 weeks) or cervical insufficiency
-Early pregnancy loss (which we are defining as before 20 weeks
-Placenta previa
-Placental abruption
-Rarely, uterine rupture or vasa previa
Cervical, vaginal, or uterine pathology (eg, polyps, inflammation/infection, trophoblastic disease) and nontubal ectopic pregnancy are other etiologies.
•Diagnostic evaluation – Diagnostic evaluation is shown in the algorithm (algorithm 3) and is different for pregnancies less than 20 weeks (see 'Evaluation' above) versus those 20 weeks or more. (See 'Evaluation' above.)
•Precautions during evaluation – Digital examination of the cervix should be avoided in patients presenting with bleeding in the second half of pregnancy until placenta previa has been excluded by ultrasound examination because digital examination of a placenta previa can cause immediate, severe hemorrhage. (See 'Evaluation' above.)
●Management of RhD-negative patients: For patients with vaginal bleeding who are RhD-negative, we recommend anti-D immune globulin to protect against RhD alloimmunization (Grade 1B). (See "RhD alloimmunization: Prevention in pregnant and postpartum patients".)
