INTRODUCTION — Second-trimester pregnancy termination comprises approximately 10 to 15 percent of abortions performed annually worldwide [1,2]. The United States Centers for Disease Control and Prevention (CDC) reported that, in 2018, approximately 8 percent of abortions were performed between 14 to 20 weeks and 1 percent at or after 21 weeks .
Second-trimester abortion is associated with more morbidity and mortality and, for some patients, more social or emotional challenges than first-trimester abortion . Legal, induced abortion is rarely associated with death; from 2013 to 2017, the CDC reported 20 deaths associated with abortions in the United States, and the case-fatality ratio was 0.44 . Although the mortality risk increases by 38 percent for each successive gestational week after eight weeks, abortion always remains significantly safer than childbirth in the United States [5,6].
Similar to first-trimester abortion, second-trimester procedures can be performed surgically, with dilation and evacuation (D&E), or with induction (medication). This topic will provide an overview of issues relating to second-trimester pregnancy termination. The procedures for second-trimester termination with induction (medication) and D&E, as well as cervical preparation prior to surgical abortion, are discussed separately:
Indications and contraindications — Patients terminate pregnancies in the second-trimester for many reasons. Procedures are often performed in the second trimester because of a delay in diagnosis of the pregnancy or delay in obtaining an abortion. As an example, at one large United States public hospital, 58 percent of patients having second-trimester procedures were already beyond the first trimester by the time they obtained a pregnancy test .
For some patients, a fetal anomaly or maternal illness (eg, early onset severe preeclampsia) is not recognized or does not present until the second trimester. Midtrimester preterm premature rupture of membranes may also be an indication for pregnancy termination.
There are no contraindications to second-trimester abortion, although some patients with medical comorbidities have an increased risk of complications. However, ongoing pregnancy and delivery are also usually associated with a risk of complications in these patients. Patients with significant medical conditions should be managed by an experienced surgeon and may require consultation with an appropriate specialist (eg, cardiologist, pulmonologist).
Laws regarding abortion vary by country and by state in the United States . Most states restrict abortion after fetal viability, though the definition of viability varies by state and maternal-fetal exemptions that countermand the viability statute vary by state. Clinicians offering abortion need to become familiar with local restrictions.
Preoperative evaluation — Determining gestational age is a critical part of providing appropriate care.
The preprocedure evaluation for pregnancy termination is discussed in detail separately. (See "Overview of pregnancy termination", section on 'Preparation for procedure'.)
Counseling and informed consent — Patients planning second-trimester pregnancy termination should be offered counseling regarding the decision to terminate or continue the pregnancy. Surgical and induction options for the procedure should be reviewed. Patients should be counseled about follow-up care and potential complications of the procedure. This discussion should be documented on the procedure consent form and in the medical record.
CHOOSING DILATION AND EVACUATION VERSUS INDUCTION TERMINATION — Second-trimester pregnancy termination can be performed by dilating the cervix and evacuating products of conception (dilation and evacuation [D&E]) or by using medication to induce delivery of the fetus and placenta. D&E accounts for the great majority of second-trimester abortions in the United States [9,10]. The United States Centers for Disease Control and Prevention reported that, in 2017, uterine suction curettage was used in 94 to 98 percent of abortions at 10 to 20 weeks of gestation and 92 percent at ≥21 weeks .
Historically, in the 1970s to 1980s, D&E was preferred because it was found to result in fewer complications than the method used for induction termination at the time, hyperosmolar instillation or oxytocin alone [11-16]. Most of the morbidity originally associated with second-trimester induction termination derived from prolonged induction times. The introduction of induction regimens with prostaglandins and progesterone antagonists has narrowed the safety gap between surgical and medical methods by shortening the interval from induction to complete abortion.
Induction termination and D&E are both safe procedures throughout the second trimester; types of morbidity vary. For example, patients undergoing D&E risk uterine perforation with need for surgical repair, whereas patients undergoing medical abortion confront higher rates of hemorrhage and infection. Patients with different medical histories might have reason to fear one type of complication more than another, influencing their selection of procedure.
Given the available data and other considerations, the choice depends mainly upon patient preference and the availability of a clinician with the skills and experience to provide one or both approaches. The clinician and patient should engage in shared decision-making to consider all the factors. For patients planning second-trimester pregnancy termination, we suggest D&E for those who prefer a procedure with greater control over timing and less experience of the procedure. We suggest induction (medication) abortion for patients who place a high value on avoiding surgery or have a reason to prefer an intact fetus and who are willing to accept more discomfort and awareness during the procedure and a chance of additional surgical intervention.
Outcomes — Both D&E and induction abortion in the second trimester are safe and effective, but D&E is preferred by most patients . In addition, approximately 8 percent of patients who undergo induction abortion require a surgical procedure for retained placenta. (See "Second-trimester pregnancy termination: Induction (medication) termination", section on 'Retained placenta'.)
There are few well-designed studies comparing the two approaches [17,18]. Randomized trials are difficult to conduct because patients often decline to be randomly assigned due to a strong preference for D&E (eg, in one trial, 38 percent of the patients recruited declined randomization and 67 percent of these wanted D&E ).
The only completed randomized trial found that complication rates were comparable, but induction abortion was associated with more adverse effects and a risk of subsequent D&E for retained products of conception. This trial (n = 122) compared D&E and induction abortion (mifepristone and misoprostol) at 13 to 20 weeks of gestation . In terms of efficacy, 10 percent of patients in the induction group underwent a subsequent procedure for retained products of conception. The rate of complications was comparable for surgical and induction procedures (12.0 versus 11.5 percent), but the type of complication varied by the type of abortion: Blood loss >500 mL was more likely in the surgical group and retained placenta in the induction group. As noted, induction abortion was more likely to result in a subsequent procedure (10 percent compared with 2 percent in the surgical group). Patients in the surgical group experienced significantly lower rates of some adverse effects: unexpected overnight stay (0 versus 31 percent) and uterine bleeding heavier than menses (4 versus 37 percent); moderate to severe pain was also less common in the surgical group, but this did not reach statistical significance (23 versus 43 percent). Patients in the surgical group found the procedure more acceptable (100 versus 53 percent would choose the same procedure in the future). This trial was limited by a lack of statistical power and a low follow-up rate (60 percent).
Advantages and disadvantages
Dilation and evacuation
●Advantages of D&E include:
•Decreased procedure duration and predictable timing – Although patients usually undergo one to two days of cervical preparation, experienced surgeons can perform uterine evacuation in less than 30 minutes once the cervix is dilated. Induction abortion, by contrast, may take as long as 24 hours or longer.
•Decreased cost – D&E usually occurs in an outpatient facility. Induction abortion often requires admission to a higher-cost labor and delivery unit .
•Medical conditions that required controlled timing of the procedure – The controlled timing of D&E permits planned procedures for patients whose medical conditions may worsen peripartum. Patients with bleeding diatheses, cardiac, and other maternal conditions often benefit from scheduled surgical procedures rather than less-predictable induction procedures. Patients with multiple prior uterine surgeries and placenta previa can also undergo safe D&E, reducing risks of uterine rupture or hemorrhage.
●Disadvantages of D&E include:
•Risk of uterine perforation – Uterine perforation is a potential risk of D&E and requires further surgical intervention. (See "Second-trimester pregnancy termination: Dilation and evacuation", section on 'Uterine perforation'.)
●Advantages of induction include:
•Desire for an intact fetus – Some patients choose labor induction to avoid fetal destruction associated with D&E. This may be due to a desire to hold the fetus. It might also provide an intact fetus for morphologic evaluation, especially when congenital anomalies are present. Representative pathologic examination may be possible with either intact D&E or standard D&E, depending on the diagnosis in question .
●Disadvantages of induction include:
•Increased experience of the procedure – In induction abortion, the patient experiences uncomfortable effects (bleeding, cramping, nausea, vomiting) and these occur over a longer period of time during and after the procedure than with D&E . The patient also has a greater awareness of the process of terminating the pregnancy. Many patients find that the predictability of D&E and avoiding the memory of prolonged labor make D&E less emotionally burdensome than induction abortion [21-23].
•Unpredictability of the timing of delivery
•Risk of hemorrhage – Second-trimester induction termination is generally associated with a higher volume of blood loss than D&E in most studies, although the opposite was found in the trial described above [18,24-26]. (See "Second-trimester pregnancy termination: Dilation and evacuation", section on 'Hemorrhage'.)
•Risk of retained placenta necessitating surgical removal
Procedure setting — Second-trimester D&E is typically performed in an outpatient setting, either a specialty women's health clinic, a clinician's office equipped with a procedure room, or an ambulatory surgery center.
Second-trimester induction most commonly occurs in hospitals on a labor and delivery unit or a family planning unit within the hospital. Induction procedures can be performed in outpatient settings, with the appropriate medical staff and equipment to provide ongoing administration of induction agents, analgesia and anesthesia, monitoring of patient status, delivery of the fetus and placenta (timing is often unpredictable), and, if needed, emergency surgical management (in case of a need for immediate evacuation of either fetus or placenta) or emergency transport to an inpatient facility.
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) . Also among the over 12,000 second trimester or later 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 (2.6 versus 2.6 percent).
Clinics or hospitals that provide pregnancy termination must have the appropriate medical staff, equipment, and medication to perform the procedure and manage complications and to provide analgesia and anesthesia. The National Abortion Federation, a professional organization of abortion providers in the United States, Canada, Mexico, and Colombia, has issued clinical policy guidelines regarding medical personnel and facilities that provide pregnancy termination . These stipulate that abortions should be provided by a licensed practitioner. The minimum requirements for a facility include presence on-site of a medical staff member with updated basic life support certification; an oxygen delivery system, oral airways, self-inflating respirator bags, and bronchodilators; and uterotonics and vasopressors, including epinephrine. In settings in which opioids or benzodiazepines are used, appropriate antagonists must be available.
It is useful for outpatient clinics to have written protocols to address emergencies, particularly indications for emergency transport to a hospital and contact information for personnel who are able to be immediately available to facilitate transport.
ABORTION TECHNIQUES AND PROTOCOLS
Cervical preparation for dilation and evacuation — Cervical preparation is performed before second-trimester dilation and evacuation procedures to decrease cervical trauma and facilitate the evacuation of the uterus. These procedures are described separately. (See "Pregnancy termination: Cervical preparation for surgical procedures" and "Second-trimester pregnancy termination: Dilation and evacuation".)
Induction abortion — Induction or medication abortion involves the administration of medication through one of a variety of routes to induce labor and deliver the fetus. Patient preparation, protocols, complications, and outcome are discussed separately. (See "Second-trimester pregnancy termination: Induction (medication) termination".)
FOLLOW-UP — Many clinicians schedule a follow-up visit at two weeks. In settings where patients live a long distance from abortion facilities, it is appropriate to schedule follow-up with another clinician, to offer routine phone follow-up, or to offer patient follow-up on an as-needed basis .
Complications are likely to present before a routine scheduled follow-up visit. The patient should be given detailed instructions regarding signs and symptoms of complications. Patients should be advised to call their provider if they experience any of the following symptoms:
●Vaginal bleeding that soaks one to two pads hourly for two consecutive hours
●Pelvic or abdominal pain that is severe or persistent
Most abortion patients should be counseled about contraception. Postabortal contraception is discussed separately. (See "Contraception: Postabortion".)
Patients may lactate following second-trimester abortion and should be counseled about comfort measures, including use of ice, compression with a tight sports bra, and avoiding breast stimulation. (See "Overview of the postpartum period: Normal physiology and routine maternal care", section on 'Breast engorgement'.)
Uterine anomaly — Approximately 2 to 4 percent of patients have some type of congenital uterine anomaly, including uterine septa, bicornuate uteri, or complete duplication of both uterus and cervix . Uterine anomalies increase the likelihood of failed dilation and evacuation (D&E) [31,32]. Indeed, failed abortion may lead to a diagnosis of a uterine malformation . Intraoperative ultrasound greatly facilitates surgical evacuation in the setting of uterine anomalies.
There is no evidence that induction abortion requires a different regimen for patients with uterine anomalies.
Uterine anomalies are discussed in detail separately. (See "Congenital uterine anomalies: Clinical manifestations and diagnosis".)
●Placenta previa and low-lying placenta – The optimal method for termination (ie, D&E, medical induction) of pregnancies complicated by placenta previa and low-lying placenta is unclear. Given concern for hemorrhage, the author performs D&E for all patients with placenta previa and most patients with a low-lying placenta. Medical induction is an acceptable alternative for patients with a low-lying placenta, especially those 11 to 20 mm from the internal os, who prefer to avoid surgical management.
Placental abnormalities do not appear to preclude the use of cervical preparation with osmotic dilators prior to termination with D&E. (See "Pregnancy termination: Cervical preparation for surgical procedures", section on 'Approach by gestational age'.)
Data on the safety of termination by D&E versus medical induction and use of osmotic dilators in patients with placental previa are limited.
•In one retrospective study including 11 patients with placenta previa undergoing pregnancy termination at 12 to 20 weeks, 4 underwent D&E and 7 underwent medical termination; rates of blood loss were similar between groups . One patient in the medical termination group developed serious bleeding and required blood transfusion. Eight of the 11 patients had laminaria placed before the procedure, and none of these patients bled before, during, or after insertion.
•In two retrospective studies including 31 patients with placenta previa undergoing second-trimester pregnancy termination by D&E after laminaria placement, none experienced excessive bleeding with laminaria insertion or required blood transfusion due to procedure-related hemorrhage; operative time was comparable to patients without complete previa [35,36].
Clinicians contemplating medical induction of second-trimester patients might also extrapolate from data for inducing term gestations complicated by low-lying placenta, especially those with a placenta 11 to 20 mm from the cervical os. In a meta-analysis including 10 cohort studies (approximately 600 patients) of vaginal delivery in patients with low-lying placenta (defined as a distance of 0 to 10 and 11 to 20 mm from the internal os) versus without (ie, >20 mm from the internal os), patients with placentas ≤10 mm compared with 11 to 20 mm and >20 mm from the cervical os had a higher risk of emergency cesarean delivery due to intrapartum hemorrhage (45, 14, and 10 percent, respectively) . Rates of postpartum hemorrhage were similar between groups. This is discussed in more detail separately. (See "Placenta previa: Management", section on 'Delivery of patients with a low-lying placenta'.)
Uterine artery embolization (UAE) or feticide prior to second-trimester pregnancy termination may help reduce blood loss, but the data are even more limited [38-40]. Until additional information is available regarding the safety and efficacy of these methods prior to termination, use should be considered on an individualized basis.
●Placenta accreta spectrum (PAS) – Suspected PAS is often managed with gravid hysterectomy (ie, hysterectomy with the fetus remaining in situ) or a "double set-up" D&E (in which the patient and operating room are prepped for emergency hysterectomy, if needed), depending on the degree of concern for placental invasion and the patient's future reproductive plans. These procedures should be performed in hospitals capable of managing life-threatening hemorrhage.
Small series have described management with UAE (prophylactic or postprocedure), fetal extraction via hysterotomy, medical induction, or D&E [41-43]. In a few cases, the placenta was removed, but in most cases, it was left in situ, with hysteroscopic resection performed under ultrasound or laparoscopic guidance at a later date when the placenta was nonfunctional (normal human chorionic gonadotropin level and reduced blood flow on Doppler at the placental interface). Representative studies include:
•In one retrospective study including 29 patients with PAS undergoing second-trimester termination, 7 patients underwent prophylactic UAE followed by hysterotomy (placenta was removed), and the remainder underwent medical induction followed by adjuvant treatment for the remaining placenta (eg, UAE, methotrexate, mifepristone, D&C) . All three patients (10 percent) requiring hysterectomy were in the hysterotomy group. Although this study utilized adjuvant methotrexate, there is no convincing evidence that methotrexate improves outcomes in these patients, and there is risk for potential harm (eg, methotrexate-related toxicity) ; thus, we strongly caution against methotrexate use in this setting.
•In another retrospective study including seven patients with PAS undergoing postprocedure UAE for management of hemorrhage after second-trimester D&E, three patients (43 percent) were treated successfully and four (57 percent) required hysterectomy (in one patient, a prophylactic, rather than postprocedure, UAE was performed) ; placentas were removed at the time of D&E in all patients.
The diagnosis and management of PAS disorders are discussed in more detail elsewhere. (See "Placenta accreta spectrum: Clinical features, diagnosis, and potential consequences" and "Placenta accreta spectrum: Management".)
Prior uterine scar — A uterine scar from a prior cesarean delivery or myomectomy is not an absolute contraindication to induction abortion, but many clinicians prefer D&E for these patients. Uterine rupture is a risk of misoprostol use at any time during pregnancy. The risk is higher in patients with a uterine scar from a prior cesarean delivery . (See "Second-trimester pregnancy termination: Induction (medication) termination", section on 'Uterine rupture' and "Misoprostol as a single agent for medical termination of pregnancy", section on 'Risk factors for uterine rupture'.)
It is uncertain whether a surgical approach entirely eliminates the risk of uterine rupture. During the process for a D&E, the uterus contracts in response to the insertion of osmotic dilators and the surgery itself, and with use of misoprostol or other agents as pharmacologic ripening agents or uterotonics. Theoretically, some events that are classified as a uterine perforation at the time of D&E on a scarred uterus may represent an occult uterine rupture.
Multifetal gestation — Multifetal gestation is managed in the same way as a singleton pregnancy for second-trimester abortion. There is no evidence that a modification is required of the surgical technique or medication regimen, though patients might confront a higher risk of uterine atony and hemorrhage due to greater uterine size. Operators should manage uterine atony as they do at similar gestational size.
Fetal anomaly or fetal demise — Second-trimester abortion is often performed for the indication of a fetal anomaly. Diagnosis of fetal anomalies and counseling for patients undergoing termination for a fetal anomaly are discussed separately. (See "Overview of antepartum fetal assessment" and "Pregnancy termination and potential psychiatric outcomes", section on 'Termination for fetal anomalies'.)
For fetal demise, management of uterine evacuation is generally the same as induced abortion and morbidity is similar, except that risk of transfusion may be higher with intrauterine fetal demise  Management of fetal demise is discussed in detail separately. (See "Stillbirth: Maternal care".)
Chorioamnionitis — Midtrimester chorioamnionitis may develop in the presence of preterm premature rupture of membranes. This may occur spontaneously and, in some cases, midtrimester rupture of membranes is the indication for pregnancy termination. Alternatively, it may develop after insertion of osmotic dilators or during a prolonged induction procedure. (See "Prelabor rupture of membranes before and at the limit of viability", section on 'Chorioamnionitis'.)
Patients with chorioamnionitis present with fever and other possible findings (pelvic and abdominal pain, uterine contractions, purulent cervical discharge). Uterine evacuation is the cornerstone of treating second-trimester chorioamnionitis. No studies have evaluated the relative benefits of surgical versus medical abortion in this setting.
For patients who are hemodynamically stable and have early chorioamnionitis, surgical or induction abortion may proceed in the same manner as for other patients. In our practice, if a patient develops a persistent temperature elevation >100.4°F, we treat with antibiotics, in the same manner as chorioamnionitis during labor. (See "Intraamniotic infection (clinical chorioamnionitis)", section on 'Antibiotic therapy'.)
Given high mortality rates associated with septic abortion, evacuation should be expedited for patients who are overtly septic. The best option for the patient must be individualized, and the surgeon should choose the one that best expedites uterine evacuation. Approaches include:
●Place osmotic dilators to prepare for D&E. There is no evidence that use of osmotic dilators exacerbates infection in patients with chorioamnionitis. Some patients with overt sepsis have already begun laboring and might require less cervical preparation than uninfected patients.
●Initiate an effective induction protocol. Osmotic dilators may be placed or mifepristone administered concurrent with initiation of uterotonics to begin the induction to allow the flexibility to convert to D&E if induction becomes prolonged. Unfortunately, placement of osmotic dilators may prolong induction abortion intervals in some cases [47-49].
Failed induction — Despite use of an appropriate induction regimen, some patients initially fail to abort. It is appropriate, in such cases, to either treat the patient with another cycle of mifepristone and misoprostol or to divert to D&E abortion. Hysterotomy abortion is rarely necessary .
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
●Second-trimester (14 to <28 weeks of gestation) pregnancy termination comprises 10 to 15 percent of the approximately 42 million abortions performed annually worldwide. (See 'Introduction' above.)
●Indications for second-trimester abortion include socioeconomic and psychosocial factors (often in cases of a delay in diagnosis of the pregnancy or delay in obtaining an abortion), fetal anomaly, preterm premature rupture of membranes, or maternal illness. There are no contraindications to second-trimester abortion, although some patients with medical comorbidities have an increased risk of complications. (See 'Indications and contraindications' above.)
●Second-trimester pregnancy termination can be performed as a surgical evacuation of the uterus (dilation and evacuation [D&E]) or by using medication to induce delivery of the fetus and placenta. (See 'Choosing dilation and evacuation versus induction termination' above.)
●Both D&E and induction methods are safe and effective options for second-trimester pregnancy termination. The choice depends mainly upon patient preference and the availability of a clinician with the skills and experience to provide one or both approaches. For patients planning second-trimester pregnancy termination (see 'Choosing dilation and evacuation versus induction termination' above):
•We suggest D&E for those who prefer a procedure with greater control over timing and less experience of the procedure (Grade 2C).
•We suggest induction (medication) abortion for patients who place a high value on avoiding surgery or have a reason to prefer an intact fetus and who are willing to accept more discomfort and awareness during the procedure, a larger blood loss, and a chance of additional surgical intervention (Grade 2C).
●The patient should be given detailed instructions regarding signs and symptoms of complications, including fever, excessive vaginal bleeding, or severe or persistent pelvic or abdominal pain. Many clinicians schedule a follow-up visit at two weeks after second-trimester pregnancy termination. Options for contraceptives are typically part of counseling before and after the procedure. (See 'Follow-up' above.)
●Patients with higher risk pregnancies (eg, uterine and placental abnormalities, prior uterine scar) can be managed with second-trimester abortion, but the approach may vary. (See 'Special circumstances' above.)