INTRODUCTION — Termination of pregnancy by uterine aspiration (also known as aspiration curettage, suction curettage, dilation and curettage, dilation and evacuation, or surgical abortion) is the most commonly used method of abortion in the United States [1]. Uterine aspiration is commonly performed up through 14 weeks of gestation, though some clinicians offer uterine aspiration in the second trimester. Medication abortion is safe and effective up to 11 weeks of gestation [2,3]. Most abortions in the United States are performed in the first trimester; in 2018, 92 percent were performed at ≤13 weeks, with over half (52 percent) of these abortions being performed as uterine aspiration [1]. First-trimester uterine aspiration is generally performed in the outpatient setting and is less costly than procedures done in the operating room [4]. In the United States, 80 to 90 percent of uterine aspiration procedures are performed in ambulatory settings [5].
First-trimester surgical abortion is reviewed here. An overview of pregnancy termination, including a discussion on how to choose between a medication and surgical abortion, as well as first-trimester medical abortion, are discussed elsewhere.
●(See "Overview of pregnancy termination".)
●(See "First-trimester pregnancy termination: Medication abortion".)
Management of second-trimester pregnancy terminations are discussed separately.
●(See "Overview of second-trimester pregnancy termination".)
●(See "Second-trimester pregnancy termination: Induction (medication) termination".)
●(See "Second-trimester pregnancy termination: Dilation and evacuation".)
COUNSELING REGARDING OPTIONS — Patients who request first-trimester medication abortion must be counseled about the available options, be resolute in their decision to terminate the pregnancy, and give informed consent. Some states have regulations regarding consent for abortion care. Clinicians should be aware of their state and federal guidelines. (See "Counseling in abortion care".)
Medication abortion and aspiration abortion are both safe and effective procedures for appropriately selected patients [6]. The choice between the two methods is discussed elsewhere. (See "Overview of pregnancy termination", section on 'First trimester'.)
PREPROCEDURE PLANNING
Contraindications — Contraindications to first-trimester aspiration abortion include inability to obtain informed consent and anatomic conditions (eg, fibroids) that restrict access to the uterine cavity.
Many medical conditions that increase risk of complications with first-trimester abortion also increase risk of continued pregnancy. Thus, when abortion is desired in a patient with comorbidities, the relative increased risk of abortion must be compared with the increased risk if pregnancy were to continue.
Procedure setting — The vast majority of first-trimester abortions in the United States are performed in an outpatient clinical setting. There are no absolute indications for hospital-based terminations. Most patients with stable, chronic medical conditions may obtain abortions safely as outpatients.
Various types of outpatient settings appear to be safe for abortion procedures. In a study of 50,111 abortions from a United States private insurance database, across all types of procedures, the incidence of adverse events was comparable for procedures performed in either an ambulatory surgery center or office-based setting (any adverse event: 3.3 versus 3.3 percent; major event: 0.3 versus 0.3 percent) [7]. Also among the over 23,000 first-trimester aspiration abortion procedures in the study, there was no difference in the incidence of adverse events associated with ambulatory surgery centers compared with office-based settings (2.2 versus 2.6 percent).
The clinician should evaluate each patient and determine the best setting for an aspiration abortion depending upon the patient's history and status, provider experience level, resources at their clinic, and available resources for referral. Otherwise, admission to a hospital prior to uterine aspiration is generally not needed. Hospital admission after uterine aspiration is rare and the criteria for this depend on severity of complications.
Patients who are in need of an abortion and who are unstable or those already hospitalized for acute illnesses or other medical conditions (such as decompensated heart failure or severe symptomatic anemia) may be best managed as an inpatient. Procedures in patients with obstetric issues such as suspected placental implantation abnormalities including placenta accreta in the late first trimester, which may require urgent surgical intervention, may be best performed in a hospital setting.
Some geographic areas have limited access to abortion care and hospital-based care may not be readily available. For patients with medical comorbidities in such areas, outpatient or ambulatory care centers with deep sedation or higher-level staffing (eg, anesthesiologist, certified nurse anesthetist) are appropriate alternatives.
PREPROCEDURE EVALUATION AND PREPARATION
History — Prior to first-trimester aspiration abortion, clinicians should elicit a targeted medical history focusing on obstetric, gynecologic, relevant medical, surgical, and psychosocial history, as well as medications and allergies. Particular attention should be given to any report of cardiovascular disease, respiratory disease, and bleeding or clotting disorders including anticoagulant use, bleeding disorders, thrombophilias, or severe anemia.
Physical examination and ultrasound — Physical examination includes:
●Vital signs
●Gestational age estimated by uterine size on pelvic examination
●Uterine flexion assessment by pelvic examination and/or ultrasound if available
●Cardiac and pulmonary physical examination (and airway assessment for patients in whom moderate or deep sedation is planned)
If uterine size on physical examination is inconsistent with expected gestational age, pelvic ultrasound may be done to evaluate the accuracy of the gestational age and evaluate uterine anatomy (eg, fibroids).
Ultrasound is also used if ectopic pregnancy or early pregnancy loss is suspected. (See "Ectopic pregnancy: Clinical manifestations and diagnosis", section on 'Clinical presentation' and "Pregnancy loss (miscarriage): Ultrasound diagnosis".)
Uterine aspiration may be done in the setting of low-grade fever (≤100.4°F, or 38°C). For higher fevers or if clinically significant infection is suspected, the procedure may be completed or delayed depending on clinician assessment of overall medical status and, if deemed safe, patient comfort and preference.
If uterine tenderness is present on physical examination, the clinician should evaluate for uterine infection and treat appropriately. Uterine aspiration may be performed in the setting of uterine infection, as long as the patient is evaluated and found to be stable, any discomfort is tolerable to the patient, and appropriate management and follow-up is possible [8-11].
Laboratory testing — Laboratory evaluation typically includes confirmation of pregnancy by urine pregnancy test or ultrasound, hemoglobin/hematocrit, Rh typing, and testing for gonorrhea and chlamydia infection in select patients. This is discussed in detail separately. (See "Overview of pregnancy termination", section on 'Laboratory testing'.)
Alloimmunization prevention — Administration of anti-D immune globulin to D-negative patients is discussed in detail elsewhere. (See "Overview of pregnancy termination", section on 'Alloimmunization prevention' and "RhD alloimmunization: Prevention in pregnant and postpartum patients", section on 'Anti-D immune globulin'.)
Antibiotic prophylaxis — We recommend antibiotic prophylaxis to prevent infection for patients undergoing first-trimester uterine aspiration abortion. Benefits of this have been demonstrated consistently in randomized trials [12,13]. In a meta-analysis of randomized trials of patients who underwent first-trimester uterine aspiration, pooled results from 15 trials showed that antibiotic prophylaxis compared with placebo resulted in a lower rate of upper genital tract infection (5.8 versus 9.4 percent, risk ratio 0.59, 95% CI 0.46-0.75) [13]. Multiple different regimens were used, and the analysis did not find one class of antimicrobials to be superior.
Choice of agent and regimen is guided more by known efficacy and bioavailability of antimicrobials and clinical experience than data since studies of this issue are few and have not consistently studied any particular regimen [8,14,15]. Studies have tended to investigate regimens with multiple doses, two or more antibiotics, and regimens that include pre- and postoperative administration. However, current practice in the United States is to use a single dose of one agent preoperatively.
The highest quality data regarding a single preoperative dose are from a randomized trial that compared doxycycline (400 mg) or metronidazole (400 mg) with placebo [16]. The trial included 3412 patients in low-resource countries (Malawi, Pakistan, Tanzania, and Uganda) who were undergoing uterine aspiration for miscarriage. Preoperative antibiotics resulted in lower rates of pelvic infection; the magnitude of effect differed depending upon whether strict diagnostic criteria for infection were used (antibiotics: 1.5 versus placebo 2.6 percent, risk ratio [RR] 0.60, 95% CI 0.37-0.96) or less strict diagnostic criteria (4.1 versus 5.3 percent, RR 0.77, 95% CI 0.56-1.04). These data support use of a single antibiotic dose prior to uterine aspiration rather than no antibiotics; however, they do not compare a single dose with a multidose regimen. The generalizability of these data are limited if applied to high-resource settings or pregnancy termination procedures [17].
The Society of Family Planning and American College of Obstetricians and Gynecologists (ACOG) both advise doxycycline administered preoperatively as the preferred antimicrobial (table 1) [8,14]. However, because of fluctuations in availability and cost of doxycycline, commonly used alternatives include azithromycin and metronidazole. The Royal College of Obstetricians in the United Kingdom advises preoperative administration of either doxycycline or azithromycin [15].
Prophylactic antibiotics should ideally be given the day of procedure. They are typically given one hour prior to the procedure, but may be given up to 12 hours prior [8]. Typical antibiotic regimens include (table 2):
●First choice – Doxycycline (200 mg orally, one dose) before the procedure [14].
●Alternatives
•Metronidazole (500 mg orally, one dose) before the procedure. This is a commonly used regimen and is effective based on clinical experience, but has not been well studied [18].
•Azithromycin (500 mg orally, one dose) before the procedure. This is a commonly used regimen and is effective based on clinical experience, but has not been well studied [18]. We prefer 500 mg rather than 1000 mg because it causes less nausea.
Venous thromboembolism prophylaxis — Because first-trimester uterine aspiration is a minor procedure with low risk of venous thromboembolism, in accordance with American College of Chest Physicians guidelines, no pharmacologic or mechanical prophylaxis is recommended other than early ambulation [19]. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)
PAIN MANAGEMENT — The pain associated with a first-trimester uterine aspiration may be alleviated by a variety of analgesics as well as nonpharmacologic methods. In some patients, pain is adequately controlled with nonsteroidal anti-inflammatory drugs (NSAIDs), verbal support, and local anesthesia. Oral or intravenous (IV) sedation may offer enhanced pain control. Since most first-trimester abortions are performed in the outpatient setting, it is uncommon to administer deep sedation. Clinicians may find that an individualized analgesia plan to match patient preferences and expectations is most appropriate for their practice [20].
In general, most clinicians use the following basic approach:
●Administer an NSAID – We use ibuprofen 600 to 800 mg orally, typically 30 to 60 minutes before the procedure.
●Paracervical block with a local anesthetic (figure 1) – We use 20 mL of buffered 1% lidocaine, injected prior to cervical dilation. An alternative is 1% chloroprocaine, which has a more favorable risk-to-benefit ratio if injected into the vascular system of a pregnant patient. Chloroprocaine is an ester that is a substrate for blood borne esterases, and is partially metabolized prior to reaching the heart, which is not the case with lidocaine or bupivacaine.
●Verbal support during the procedure.
●Oral or IV sedation may be given based upon the needs and preferences of the patient, experience and preference of the clinician, and availability of medications and equipment.
•When only oral medications are available:
-We most commonly give a sedative, lorazepam 0.5 to 2 mg sublingual, 30 minutes prior to the procedure.
-We view use of an opioid analgesic as optional as it has no proven benefits. If clinically indicated, we use 1 to 2 tablets of hydrocodone/acetaminophen 5/325 mg, typically 30 to 60 minutes before the procedure.
•When IV sedation is available, we use fentanyl 100 mcg and midazolam 2 mg at the start of the procedure and follow local conscious sedation protocols. Following the administration of IV narcotics and benzodiazepine medications, cardiorespiratory monitoring by a clinician who is not performing the procedure is mandatory.
Nonsteroidal anti-inflammatory drugs — Premedication with ibuprofen 600 to 800 mg 30 minutes prior to procedure reduced both intraoperative and postoperative pain in a randomized trial [21]. Intramuscular ketorolac was not found to be superior to oral ibuprofen for pain control in another randomized trial [22]. However, ketorolac combined with lidocaine as a paracervical block agent improved reported pain after cervical dilation, but not other procedure-related pain, when compared with oral ibuprofen and a standard lidocaine block [23].
Paracervical block — Use of a paracervical block for local anesthesia is nearly universal in first-trimester uterine aspiration [24]. In one randomized trial (n = 120), patients were assigned to a paracervical block with 20 mL of 1% buffered lidocaine or a sham block. Patients receiving the paracervical block had significantly lower pain scores with cervical dilation and aspiration and higher satisfaction scores for pain control and the procedure overall [25].
The goal of local anesthesia is to target innervation of the uterine cervix and fundus (figure 1). Paracervical block technique and medications are discussed in detail separately. (See "Pudendal and paracervical block", section on 'Women undergoing gynecologic procedures'.)
Sedatives and opioids — Sedation is often given for a first-trimester aspiration abortion procedure, either with oral or IV medications. However, practices vary among providers and clinical settings, and many patients undergo uterine aspiration comfortably with no sedation.
In one randomized control trial of 130 patients comparing oral sedation (oxycodone 10 mg and lorazepam 1 mg sublingual) with IV sedation (fentanyl 100 mcg and midazolam 2 mg), adjusted intraoperative pain scores were significantly less with IV sedation (36.3 versus 61.2 on verbal rating scale of 0 to 100) [26].
Studies of the individual effects of oral sedatives have not demonstrated improved pain control during first-trimester abortion when added to standard medication protocols that include ibuprofen and a paracervical block [27,28]. Other effects were significant: Oral midazolam reduced preoperative anxiety and postoperative nausea but increased partial amnesia and postoperative sleepiness compared with placebo [27]; hydrocodone/acetaminophen increased postoperative nausea compared with placebo without other benefit [28].
IV sedation must be administered by a licensed practitioner, usually a registered nurse or a higher-level clinician (eg, physician or certified nurse midwife), and all patients receiving moderate sedation or deeper must be monitored by an individual other than the provider performing the procedure. As this higher level of staffing is not available in all settings in which first-trimester abortion is performed, many providers rely on the adjuvant use of oral sedatives despite the lack of evidence demonstrating improved pain control. Some outpatient clinics may have the ability to directly dispense medications, while other providers may prescribe benzodiazepines or opiates in advance for the patient to bring with them for administration in clinic prior to the procedure. Any patient taking sedating medications, whether oral or IV, should be instructed that they cannot drive themselves home after the procedure and must have a confirmed person to take them home after the procedure. Requiring a driver, particularly for a procedure widely associated with social stigma, may be a barrier for many patients and should be kept in mind when planning the use of sedation.
Further information on patient selection and administration of IV sedation medications can be found separately. (See "Procedural sedation in adults outside of the operating room: General considerations, preparation, monitoring, and mitigating complications".)
Nitrous oxide — A randomized controlled trial of 140 patients showed no difference in mean pain scores or patient satisfaction when comparing the analgesic effect of nitrous oxide with oxygen (N2O/O2) to oral hydrocodone/acetaminophen and lorazepam during first-trimester uterine aspiration [29]. While there is no evidence for improved pain control with the use of nitrous oxide over IV or oral sedatives, the limited duration of side effects and the ability to drive oneself home afterwards may be advantageous in the outpatient setting for some patients. This is especially advantageous in sparsely populated states where patients drive hundreds of miles to access abortion services. In addition, one study of nitrous oxide for pain control in hysteroscopic sterilization, in which the N2O/O2 concentration was titrated up to a maximum of 70:30 more frequently than in the uterine aspiration study group, did demonstrate benefit over oral medications alone (mean pain scores on 100 mm visual analog scale of 22.8 versus 54.5, p <0.001) [30].
Additional support measures — In the awake patient, a designated support person can provide vocal support and reassurance to decrease anxiety, which in turn may decrease pain. This method may include distractions through unrelated conversation or guided breathing and relaxation techniques. The support person may be a friend, partner, or a trained staff member or doula who sits close to the patient during the procedure. Randomized trials and qualitative research point to positive outcomes from using abortion doula services, such as a reduced need for additional clinical support staff [31-33].
The use of neutral or nonspecific language during procedures has been shown in some but not all studies to reduce pain perception [34-36]. Some suggestions for neutral communication for abortion and gynecologic care are outlined in the table (table 3). Also, giving the patient some control (eg, taking a break in the middle of the procedure or requesting additional medication) may also decrease anxiety.
CERVICAL PREPARATION — Cervical preparation with osmotic dilators or medications is not routinely used in first-trimester aspiration abortion because it delays the procedure, is associated with risk of complications and side effects, and does not confer proven benefit.
There are some exceptions to use of cervical preparation in first trimester. Many clinicians treat with misoprostol in clinical contexts in which dilation may be more difficult or have an increased risk of cervical injury, including:
●≥12 weeks
●Mechanical barriers to dilation (eg, prior cervical surgery, uterine fibroids)
●Nulliparas
●Adolescents (age ≤17 years) [37]
Cervical preparation for abortion is discussed in detail separately. (See "Pregnancy termination: Cervical preparation for surgical procedures", section on '12 to <14 weeks'.)
ASPIRATION PROCEDURE — First-trimester uterine aspiration is a safe procedure and has a short procedure duration. The primary components are (figure 2):
●Premedications, including antibiotics and analgesics or sedatives.
●Placing the patient in dorsal lithotomy position.
●Infection prevention measures – As in other vaginal procedures, gloves are used, but a vaginal procedure cannot be sterile. Sterile gloves are not required if the clinician utilizes a no-touch technique to maintain sterility of all instruments that pass through the cervical os. (See "Overview of preoperative evaluation and preparation for gynecologic surgery", section on 'Vaginal preparation'.)
●Administration of a paracervical block.
●Mechanical cervical dilation.
●Aspiration of the uterine contents with a manual or electric aspirator via a plastic cannula placed in the uterus.
The picture shows a typical equipment tray for manual aspiration (picture 1).
If cervical preparation is given, it is common practice to use misoprostol administered several hours before the procedure. (See "Pregnancy termination: Cervical preparation for surgical procedures", section on '12 to <14 weeks'.)
Paracervical block — Following a pelvic examination, a vaginal speculum is used to visualize the cervix. It is common practice to swab the cervix and vaginal tissue with an antiseptic solution such as povidone-iodine or chlorhexidine, although evidence does not support this as effective in preventing abortion-related infection [8].
Approximately 2 mL of local anesthetic (eg, 1% buffered lidocaine) is injected into the cervical stroma at the planned location of tenaculum placement. Adequate traction on the tenaculum will straighten the cervicouterine angle for safer passage of intrauterine instruments during dilation and aspiration. A paracervical block, typically using a total of 20 mL of local anesthetic, is administered (figure 1).
Cervical dilation — Mechanical cervical dilation is required for most aspiration procedures. Cervical dilation may not be necessary for very early gestations (less than seven weeks).
Mechanical dilation is performed to achieve the degree of dilation needed to accommodate the cannula size that is necessary to remove the pregnancy tissue. Cannulas are sized by diameter, and most clinicians choose a diameter equal to the number of weeks of gestation or 1 mm smaller. For example, at seven weeks, the tissue can be aspirated safely and effectively with a 7 mm or a 6 mm cannula. Sequential rigid dilators are passed until adequate dilation is reached to pass the desired cannula. If dilation cannot be achieved, additional cervical preparation may be warranted before proceeding with aspiration. (See "Pregnancy termination: Cervical preparation for surgical procedures".)
Uterine evacuation — Aspiration is performed with a flexible or rigid, curved or straight plastic cannula attached to a manual or electric vacuum aspirator.
Choice of cannula type is provider preference, as they can be used interchangeably with each type of aspirator. There is a clinical tendency toward use of flexible, straight cannula at early (less than 10 weeks) gestations with a manual uterine aspirator (MUA) and use of a rigid, curved cannula for later gestations with the electric vacuum aspirator (EVA).
At 10 weeks of gestation or less, MUA and EVA have similar rates of successful uterine evacuation and patient acceptability and no differences in major complication rates [38,39]; however, at very early gestations (50 days or less), pooled analysis from randomized trials showed MUA had less blood loss and less perceived pain but a longer procedure time than EVA [39]. MUA is quieter, which may make it preferable for some patients [40,41]. MUA is more portable, less expensive, and does not require electricity, which makes it favorable for use in resource-limited settings as compared with EVA.
Sharp curettage alone (without aspiration) is not effective to accomplish uterine evacuation, and the World Health Organization strongly recommends against its routine use as a standalone abortion procedure in the first trimester [42,43].
Intraoperative ultrasound guidance may be employed at the discretion of the provider, as there is no evidence for or against its practice in the first trimester. It is most often used if there is suspicion or knowledge of uterine abnormalities such as leiomyomata or a bicornuate uterus, multiple gestations, difficult cervical dilation, or procedures at a later gestational age (≥12 weeks or ≥14 weeks of gestation).
The completion of the procedure is signaled by a gritty sensation of the endometrium and the strength of the empty uterus contracting around the cannula.
TISSUE EVALUATION — After uterine aspiration is performed, most clinics perform examination of the products of conception (POC).
The POC findings that confirm a complete abortion vary by gestational age (figure 3):
●≤9 weeks of gestation – Identification of the appropriately sized gestational sac is sufficient to confirm completion of procedure.
●10 to <12 weeks – In addition to the gestational sac, fetal parts may begin to be identified.
●≥12 weeks – Four extremities, spine, calvarium, gestational sac, and placenta must all be identified.
Failed attempted aspiration abortion is rare, but it is more common at early gestations (<7 weeks) when a definitive intrauterine pregnancy may not be seen on ultrasound and POC may be more difficult to remove successfully [44-46]. A study of 1132 early abortions up to seven weeks of gestation reported a failed abortion rate of 15 per 1000 [47]. All providers inspected tissue on-site using flotation and backlighting, as is standard practice [47]. Modest reductions in failed abortion (rate of 1.3 per 1000) at <7 weeks were seen in one case series of 2399 patients, in which a resource-intensive protocol included pre- and postabortion transvaginal ultrasonography, a rigid 7 mm cannula for aspiration, and colposcopic magnification for POC examination when needed to confirm procedure completion [48,49].
Inadequate products of conception — If inadequate POC are suspected at the time of the procedure, the first-line approach is to repeat aspiration immediately. When available, we use intraoperative transabdominal ultrasound guidance to guide reaspiration, to assure the cannula is reaching the uterine fundus and pregnancy tissue. For retained pregnancies easily identified on transabdominal ultrasound prior to reaspiration, this intraoperative sonogram is often sufficient to confirm a successful evacuation. When transabdominal ultrasound does not identify a retained pregnancy, transvaginal ultrasound should be performed after reaspiration if adequate POC is still not identified. Careful attention should be paid to whether an ectopic pregnancy or uterine anomaly, which may be complicating access to the pregnancy, can be seen.
If repeat aspiration does not provide an adequate amount of POC and retained POC is still suspected or a successful abortion cannot be confirmed, serial laboratory testing of quantitative serum beta human chorionic gonadotropin (hCG) may be used.
A serum level is drawn on the day of the aspiration as a baseline, and a repeat hCG is measured in 24 to 48 hours. This should demonstrate more than a 50 percent decline to indicate a successful abortion [43,50,51]. If there is inadequate decline or a rise in hCG levels, ultrasound should be repeated to evaluate for retained POC, ongoing pregnancy, or ectopic pregnancy.
In the case of uterine aspiration for a very early gestation or if an intrauterine pregnancy was not confirmed on ultrasound prior to aspiration (eg, small fluid-filled sac lacking a yolk sac or embryo), if no gestational sac is identified in POC examination, ectopic pregnancy should be suspected and the patient should be evaluated and managed appropriately. (See "Ectopic pregnancy: Clinical manifestations and diagnosis", section on 'Diagnostic evaluation'.)
Suspected molar pregnancy — Molar pregnancy should be considered in any patient with a prior history of hydatidiform mole. Molar pregnancy may also be suspected preoperatively from characteristic ultrasound findings (the classic "snowstorm or Swiss cheese pattern" of a central heterogeneous mass in the uterus with numerous discrete anechoic spaces) or a markedly high serum hCG level. Postoperatively, a molar pregnancy may be suspected if you see hydropic swelling of the chorionic villi on examination of the POC.
In the case of suspected molar pregnancy, tissue should be sent for pathology evaluation. If molar pregnancy is suspected, our practice is to send a serum hCG on the day of uterine evacuation as a baseline in case further monitoring is required. In the event of a confirmed molar diagnosis, protocols for hCG monitoring should be followed. (See "Hydatidiform mole: Treatment and follow-up".)
RECOVERY AND FOLLOW-UP — Postprocedure recovery time is typically 20 to 30 minutes for patients who receive minimal or moderate sedation. During recovery, patient should be assessed for stable vital signs, vaginal bleeding, adequate pain control, and ability to ambulate independently at time of discharge.
While data do not support routine visits after uterine aspiration [52], warning signs that indicate need for postprocedure visit include [53]:
●Vaginal bleeding more than two maxi pads per hour for more than two hours in a row
●Cramps that are persistent and worsening despite pain medication
●Temperature ≥101°F
If the patient desires discussion about contraception and pregnancy planning this can be done on the day of the procedure [54]. Contraceptive methods can be placed, dispensed, or prescribed on procedure day. (See "Contraception: Postabortion", section on 'Initiation of contraception' and "Overview of pregnancy termination", section on 'Plan for contraception'.)
OUTCOME AND COMPLICATIONS — First-trimester aspiration abortion is a safe procedure, with an overall complication rate of 9.05 per 1000 [55]. Major complications (suspected perforation, ectopic pregnancy, hemorrhage, sepsis) are very rare (0.71 per 1000). The overall mortality rate associated with legal abortion in the United States is 0.7 per 100,000, with markedly reduced rates at lower gestations (0.1 per 100,000 at <8 weeks, 0.2 per 100,000 at 9 to 10 weeks, and 0.4 per 100,000 at 11 to 12 weeks) [56]. In the first trimester, infection is the most common cause of abortion-related mortality (31 percent), with anesthesia complications accounting for 22 percent and hemorrhage accounting for 14 percent of deaths [56]. (See "Overview of pregnancy termination", section on 'Complications'.)
Aspiration abortion procedures performed in an outpatient setting have low rates of morbidity and mortality, comparable to procedures performed within a hospital setting [57,58]. Potential immediate complications include hemorrhage, cervical laceration, and uterine perforation. These complications occurred in only 0.06 percent of 170,000 consecutive cases reported in one series from Planned Parenthood [55]. In this series, 0.07 percent of patients required hospitalization because of incomplete abortion, sepsis, uterine perforation, hemorrhage, inability to complete the procedure, or combined (intrauterine and tubal) pregnancy. Minor complications, such as mild infection, incomplete abortion requiring reaspiration in an ambulatory setting, cervical stenosis or laceration, or convulsive seizure due to administration of local anesthetic, occurred in 0.84 percent.
A systematic review of complications from first-trimester aspiration abortion included 57 studies and calculated the incidence of hemorrhage not requiring transfusion (<5 percent), major complications including hemorrhage requiring transfusion and uterine perforation requiring repair (≤0.1 percent), hospitalizations (≤0.5 percent), and repeat aspirations (<3 percent). No abortion-related deaths were reported [58].
Infection — Postabortal endometritis occurs in 5 to 20 percent of patients who undergo first-trimester aspiration abortion and do not receive prophylactic antibiotics [12]. With the use of antibiotic prophylaxis, the infection rate is reduced significantly; in the large case series of 170,000 patients, 784 (0.46 percent) experienced a mild infection and only 36 (0.021 percent) were classified with a diagnosis of sepsis [55]. In a 2015 systematic review, of the six office-based studies in which all patients received antibiotic prophylaxis, <2 percent of patients in five of these studies required outpatient treatment for presumed or diagnosed infection [58].
Postabortal pelvic infections are generally diagnosed clinically. Patients usually present with one or more of the following: fever; lower abdominal or pelvic pain; adnexal, uterine, or cervical motion tenderness on examination; friable cervix; excessive or abnormal bleeding; or abnormal vaginal discharge. Patients who are hemodynamically stable and are not toxic-appearing may be presumptively treated as an outpatient with a trial of broad-spectrum antibiotic therapy, including coverage of anaerobes, in accordance with Centers for Disease Control and Prevention guidelines for pelvic inflammatory disease. Any retained products of conception (POC) or blood clot found on ultrasound in the setting of suspected infection should be evacuated. (See "Pelvic inflammatory disease: Treatment in adults and adolescents" and 'Retained products of conception' below.)
Generalized abdominal tenderness, guarding, tachycardia, high fever, and prostration suggest peritonitis or potential sepsis. These patients require aggressive therapy with broad spectrum intravenous antibiotics, uterine re-evacuation, assessment for uterine perforation, and inpatient monitoring and support, possibly in an intensive care unit.
Hemorrhage — Postabortal hemorrhage is rare with first-trimester aspiration abortion and may result from uterine atony, cervical or vaginal lacerations, uterine perforation, or retained tissue. Our approach is similar to The Society of Family Planning guidelines which are discussed in detail separately [59]. (See "Overview of pregnancy termination", section on 'Hemorrhage'.)
Abnormal placentation is rare in the late first and early second trimester, but may result in significant bleeding with aspiration abortion. Risk factors include prior cesarean delivery or a history of other uterine surgeries (particularly if there was an incision from the endometrial cavity into the myometrium). If abnormal placentation is suspected prior to the procedure, additional precautions should be taken such as using intraoperative ultrasound, avoiding direct suction or sharp curettage over the uterine scar or area of suspected abnormal implantation, having an electric vacuum aspirator immediately available, and/or advance notification of back-up providers (eg, gynecologic surgeon or interventional radiologist). Depending on availability and access, providers may consider performing the procedure in the operating room and with blood products available. (See "Cesarean scar pregnancy".)
Cervical laceration — Cervical or vaginal trauma from first-trimester uterine aspiration is rare (≤0.1 percent) [58], but risk can be reduced by appropriate cervical preparation in patients in whom difficult mechanical dilation is anticipated. Most cervical or vaginal trauma during first-trimester uterine aspiration can be controlled with direct pressure for one to two minutes. For cervical lacerations, application of silver nitrate or ferric subsulfate (Monsel solution) may be useful. For cervical lacerations that have persistent bleeding, surgical repair with absorbable sutures is recommended.
Uterine perforation — For both first- and second-trimester procedures, the reported rate of uterine perforation is less than 0.6 percent [60-62]. Among first-trimester procedures alone, one study of 170,000 patients had only 16 cases (<0.01 percent) of uterine perforation requiring additional measures [55]. In a systematic review of first-trimester abortions, the majority of office- and hospital-based studies reported no cases of uterine perforation requiring additional surgery or hospitalization.
When uterine perforation is suspected, the aspiration procedure should be stopped to evaluate the extent of the perforation using ultrasound guidance. If there is no evidence of vascular or visceral injury and the procedure is not complete, the procedure can continue under ultrasound guidance if the remaining pregnancy tissue can be safely reached. The procedure may also be postponed for one to two weeks to allow closure of the perforation, and subsequent aspiration should be performed under ultrasound guidance. Further surgical intervention may be indicated if hemorrhage is persistent or there is evidence of visceral injury.
Expectant management of uterine perforation typically includes monitoring of vital signs and symptoms (uterine tenderness, vaginal bleeding) for one to two hours and postprocedure ultrasound to evaluate for free fluid in the pelvis. Anaerobic coverage with metronidazole 500 mg by mouth twice daily for one week is common, but no studies have addressed this practice. Further details on uterine perforation are discussed separately. (See "Uterine perforation during gynecologic procedures".)
Hematometra — Immediate postoperative pain without overt bleeding from the vagina may indicate development of hematometra. Hematometra usually presents with complaints of dull, aching lower abdominal pain, sometimes accompanied by tachycardia, diaphoresis, or nausea. The onset is usually within the first hour after completion of the procedure.
Pelvic examination reveals a large midline globular uterus that is tense and tender, or an enlarged uterine cavity filled with echogenic material on ultrasound. Treatment requires immediate uterine evacuation, permitting the uterus to contract to a normal postprocedure size. Administration of intramuscular methylergonovine maleate (0.2 mg) may be given to ensure continued contraction of the uterus [63].
Retained products of conception — Retained POC (ie, placental tissue, fetal fragments, fetal membranes) is an uncommon complication of abortion by uterine aspiration. In one series with follow-up information on 80 percent of patients who underwent pregnancy termination, retained POC were present in 4 of 672 first-trimester procedures [64].
It may be difficult to distinguish retained POC from hematometra or infectious endometritis based on clinical evaluation alone. These postabortion entities may all present with similar symptoms and examination findings: lower abdominal or pelvic pain and an enlarged or tender uterus. Hematometra is more likely when the presentation of pain is immediately postabortion (within one hour) and without heavy vaginal bleeding. Retained POC is more likely when the presentation is delayed and accompanied by heavy or persistent vaginal bleeding days or weeks after the procedure. An infectious etiology is more likely to be accompanied by fever, or when pain is not associated with sonographic evidence of retained tissue in the uterine cavity [65].
Any physical or sonographic evidence of retained POC should prompt consideration of suction curettage to complete evacuation of the uterus, especially in the acutely symptomatic patient. Misoprostol is an alternative treatment for retained POC in doses used for incomplete abortions or miscarriages: 600 mcg orally or 400 mcg sublingually [66]. One study published a misoprostol success rate of 93 percent to treat retained POC in 88 patients and a corresponding decrease in the use of repeat dilation and curettage [67].
Ongoing pregnancy — Ongoing pregnancy is more likely to be a complication of early rather than late abortion. All patients will continue to have an elevated level of hCG for a short period following pregnancy termination. Return of the serum hCG concentration to undetectable following pregnancy termination varies widely from 7 to 60 days [50]. The period of time depends primarily upon the hCG concentration at the time of termination. The hCG concentration peaks at 8 to 11 weeks of gestation at approximately 90,000 milli-international units per mL. This is in contrast with term pregnancy, for which the hCG concentration is lower. The decline in serum hCG is rapid for the first several days (half-life 9 to 31 hours) and then proceeds more slowly (half-life 55 to 64 hours) [51,68,69]. (See "Human chorionic gonadotropin: Biochemistry and measurement in pregnancy and disease".)
An ongoing intrauterine pregnancy may occur after an attempted pregnancy termination if the clinician fails to recognize a sufficient amount of gestational tissue upon examination postprocedure to verify successful completion (see 'Tissue evaluation' above). Alternatively, ongoing pregnancy may rarely result from a multiple gestation in which only one of the sacs was aborted. In one series of 12,138 consecutive abortions with careful examination of the pathologic specimen, three continuing pregnancies were later diagnosed and attributed to clinician error [45]. Two were at six weeks and one was at eight weeks of gestation. A second series reported an ongoing pregnancy rate of 1.3 per 1000 procedures for pregnancies less than six weeks of gestation [47].
The type and risk of possible damage to the ongoing pregnancy from an attempted abortion cannot be quantified. Direct or indirect injury to the developing embryo could occur. One preliminary report suggested there may be an increased risk of Moebius sequence with autism in children exposed to misoprostol in the first trimester [70]. Moebius sequence is a clinical condition characterized by ophthalmic-facial palsy and muscle or bone malformations in the limbs. It represents a cascade of events resulting from embryo trauma from varied etiologies (eg, genetic factors, environmental injuries, prolonged membrane ruptures and chorionic villus sampling). (See "Misoprostol as a single agent for medical termination of pregnancy", section on 'Teratogenicity'.)
SPECIAL CONSIDERATIONS
Multiple gestations — Uterine aspiration of multiple gestations in the first trimester can be approached in a similar fashion as a single gestation of the same duration. For example, a six-week twin pregnancy can be successfully evacuated by manual uterine aspiration through a 6 mm cannula following the same steps as for a six-week singleton.
Many providers will use ultrasound guidance for multiple gestations at an earlier gestational age than for singletons for reassurance of procedure completion, especially as it may be difficult to assess from products of conception (POC) examination if the entirety of all gestational sacs were evacuated.
Additional considerations to accommodate the increased volume of POC in multiple gestations as compared with singletons include the use of electric vacuum aspirator (EVA) over manual uterine aspirator at earlier gestational ages, and advance preparedness with uterotonics in case of excessive bleeding due to uterine atony.
Uterine anomalies and abnormalities — Uterine anomalies or abnormalities, such as large fibroids or a congenital anomaly, can pose challenges in uterine aspiration. Ultrasound guidance is extremely helpful in navigating a divided or distorted endometrial cavity. Aspiration of the nonpregnant horn of a didelphic uterus is not thought to be necessary.
Adjunctive use of misoprostol for cervical preparation may be useful even at early gestations (<12 weeks) when cervical dilation is impaired by fibroids. When large fibroids impede placement of the cannula at the fundus to reach the pregnancy, alternate instruments, such as EVA nozzle extenders may be helpful. Some providers anecdotally report modifying flexible cannulas in tandem, or inserting a moldable metal uterine sound inside a cannula to navigate placement past fibroids.
Finally, it is important to remember that when uterine aspiration is not successful due to these anatomic challenges, medication abortion is often a good alternative for gestations <10 weeks.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Pregnancy termination".)
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 topic (see "Patient education: Abortion (The Basics)")
●Beyond the Basics topic (see "Patient education: Abortion (pregnancy termination) (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Termination of pregnancy by uterine aspiration is the most commonly used abortion method in the United States, and most of these procedures are performed in the first trimester. (See 'Introduction' above.)
●The choice between medication abortion and aspiration abortion in the first trimester is based upon availability, gestational age (medication abortion is less successful in the late first trimester), and patient preference. Counseling regarding this choice is discussed in detail elsewhere. (See "Overview of pregnancy termination", section on 'Choice of procedure'.)
●Preprocedure evaluation includes history, focused general physical examination, and assessment of gestational duration. Pelvic ultrasound may be done if uterine size on examination is inconsistent with expected gestational age or if there is a suspicion of an ectopic pregnancy. Laboratory evaluation typically includes confirmation of pregnancy by high-sensitivity urine pregnancy test or ultrasound, hemoglobin/hematocrit, and Rh(D) immune globulin status for gestations >8 weeks (56 days). (See 'Preprocedure evaluation and preparation' above.)
●Pain control for first-trimester aspiration abortion with nonsteroidal anti-inflammatory drugs, verbal support, and local anesthesia. Oral or intravenous sedation may offer enhanced pain control. (See 'Pain management' above.)
●Cervical preparation with osmotic dilators or cervical ripening medications is typically not required in first-trimester aspiration abortion. Exceptions to this are patients in whom difficult mechanical dilation is anticipated or if there is an increased risk of cervical injury, including ≥12 weeks, mechanical obstruction of the cervix (eg, prior surgery), nulliparas, or adolescents. (See 'Cervical preparation' above.)
●The aspiration procedure includes positioning and preparation, administration of antibiotics and pain medications, mechanical cervical dilation, and aspiration of uterine contents with a manual or electric aspirator. After aspiration, the products of conception are examined to confirm full uterine evacuation. (See 'Aspiration procedure' above and 'Tissue evaluation' above.)
●We recommend antibiotic prophylaxis to prevent postabortion endometritis for patients undergoing first-trimester uterine aspiration abortion (Grade 1A) (table 2). (See 'Antibiotic prophylaxis' above.)
●Procedures are typically performed in an outpatient setting. Future pregnancy plans may be discussed if patients desire, and appropriate guidance given for preconception or contraceptive care. Patients should be counseled to seek medical attention if they have postprocedure symptoms, including excessive vaginal bleeding, persistent pelvic cramps, or temperature ≥100.4°F or 38°C. (See 'Recovery and follow-up' above.)
●First-trimester aspiration abortion is a safe procedure, with an overall complication rate of 9.05 per 1000. Major complications (suspected perforation, hemorrhage, sepsis) are rare. Potential complications include infection, hemorrhage, cervical laceration, uterine perforation, and retained products of conception. (See 'Outcome and complications' above.)
ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Frank W Ling, MD, and Lee P Shulman, MD, who contributed to an earlier version of this topic review.
