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Jeanmarie Morock
INTERIM UPDATE: This Practice Bulletin is updated as highlighted to reflect recent evidence regarding the use of mifepristone combined with misoprostol for medical management of early pregnancy loss. This Practice Bulletin also includes limited, focused updates to align with Practice Bulletin No. 181, Prevention of Rh D Alloimmunization .
ABSTRACT: Early pregnancy loss, or loss of an intrauterine pregnancy within the first trimester, is encountered commonly in clinical practice. Obstetricians and gynecologists should understand the use of various diagnostic tools to differentiate between viable and nonviable pregnancies and offer the full range of therapeutic options to patients, including expectant, medical, and surgical management. The purpose of this Practice Bulletin is to review diagnostic approaches and describe options for the management of early pregnancy loss.
Early pregnancy loss is defined as a nonviable, intrauterine pregnancy with either an empty gestational sac or a gestational sac containing an embryo or fetus without fetal heart activity within the first 12 6/7 weeks of gestation 1. In the first trimester, the terms miscarriage, spontaneous abortion, and early pregnancy loss are used interchangeably, and there is no consensus on terminology in the literature. However, early pregnancy loss is the term that will be used in this Practice Bulletin.
Common symptoms of early pregnancy loss, such as vaginal bleeding and uterine cramping, also are common in normal gestation, ectopic pregnancy, and molar pregnancy. Before initiating treatment, it is important to distinguish early pregnancy loss from other early pregnancy complications. Treatment of an early pregnancy loss before confirmed diagnosis can have detrimental consequences, including interruption of a normal pregnancy, pregnancy complications, or birth defects 9. Therefore, a thorough evaluation is needed to make a definitive diagnosis. In combination with a thorough medical history and physical examination, ultrasonography and serum β-hCG testing can be helpful in making a highly certain diagnosis.
Ultrasonography, if available, is the preferred modality to verify the presence of a viable intrauterine gestation. In some instances, making a diagnosis of early pregnancy loss is fairly straightforward and requires limited testing or imaging. For example, early pregnancy loss can be diagnosed with certainty in a woman with an ultrasound-documented intrauterine pregnancy who subsequently presents with reported significant vaginal bleeding and an empty uterus on ultrasound examination. In other instances, the diagnosis of early pregnancy loss is not as clear. Depending on the specific clinical circumstances and how much diagnostic certainty the patient desires, a single serum β-hCG test or ultrasound examination may not be sufficient to confirm the diagnosis of early pregnancy loss.
In cases in which an intrauterine gestation cannot be identified with reasonable certainty, serial serum β-hCG measurements and ultrasound examinations may be required before treatment to rule out the possibility of an ectopic pregnancy. A detailed description of the recommended approach to ectopic pregnancy diagnosis and management is available in Practice Bulletin Number 193, Tubal Ectopic Pregnancy 18.
Accepted treatment options for early pregnancy loss include expectant management, medical treatment, or surgical evacuation. Although these options differ significantly in process, all have been shown to be reasonably effective and accepted by patients. In women without medical complications or symptoms requiring urgent surgical evacuation, treatment plans can safely accommodate patient treatment preferences. There is no evidence that any approach results in different long-term outcomes. Patients should be counseled about the risks and benefits of each option. The following discussion applies to symptomatic and asymptomatic patients.
Because of a lack of safety studies of expectant management in the second trimester and concerns about hemorrhage, expectant management generally should be limited to gestations within the first trimester. With adequate time (up to 8 weeks), expectant management is successful in achieving complete expulsion in approximately 80% of women 19. Limited data suggest that expectant management may be more effective in symptomatic women (those who report tissue passage or have ultrasound findings consistent with incomplete expulsion) than in asymptomatic women 20 21. Furthermore, studies that included women with incomplete early pregnancy loss tend to report higher success rates than those that included only women with missed or anembryonic pregnancy loss 22.
Patients undergoing expectant management may experience moderate-to-heavy bleeding and cramping. Educational materials instructing the patient on when and who to call for excessive bleeding and prescriptions for pain medications should be provided. It also is important to counsel patients that surgery may be needed if complete expulsion is not achieved. Studies among women with early pregnancy loss typically have used ultrasound criteria, patient-reported symptoms, or both, to confirm complete passage of gestational tissue. Although there is no consensus in the literature, a commonly used criterion for complete expulsion of pregnancy tissue is the absence of a gestational sac and an endometrial thickness of less than 30 mm 23. However, there is no evidence that morbidity is increased in asymptomatic women with a thicker endometrial measurement 24. Surgical intervention is not required in asymptomatic women with a thickened endometrial stripe after treatment for early pregnancy loss. Thus, the use of ultrasound examination for any diagnostic purpose other than documenting the absence of the gestational sac is not recommended. Other follow-up approaches, such as standardized follow-up phone calls, urine pregnancy tests, or serial quantitative serum β-hCG measurements, may be useful, especially for women with limited access to follow-up ultrasound examination 25. However, these approaches have not been studied sufficiently among women with early pregnancy loss to provide meaningful guidance.
Medical management for early pregnancy loss can be considered in women without infection, hemorrhage, severe anemia, or bleeding disorders who want to shorten the time to complete expulsion but prefer to avoid surgical evacuation. Compared with expectant management, medical management of early pregnancy loss decreases the time to expulsion and increases the rate of complete expulsion without the need for surgical intervention 26.
Misoprostol-based regimens have been extensively studied for the medical management of early pregnancy loss 26. Most studies suggest that a larger dose of misoprostol is more effective than a smaller dose, and vaginal or sublingual administration is more effective than oral administration, although the sublingual route is associated with more cases of diarrhea 26. The largest randomized controlled trial conducted in the United States demonstrated complete expulsion by day 3 in 71% of women with first-trimester pregnancy loss after one dose of 800 micrograms of vaginal misoprostol 23. The success rate was increased to 84% after a second dose of 800 micrograms of vaginal misoprostol was administered if needed. Therefore, in patients for whom medical management of early pregnancy loss is indicated, initial treatment using 800 micrograms of vaginal misoprostol is recommended, with a repeat dose as needed Box 1.
Surgical uterine evacuation has long been the traditional approach for women presenting with early pregnancy loss and retained tissue. Women who present with hemorrhage, hemodynamic instability, or signs of infection should be treated urgently with surgical uterine evacuation. Surgical evacuation also might be preferable in other situations, including the presence of medical comorbidities such as severe anemia, bleeding disorders, or cardiovascular disease. Many women prefer surgical evacuation to expectant or medical treatment because it provides more immediate completion of the process with less follow-up.
Studies have demonstrated that expectant, medical, and surgical management of early pregnancy loss all result in complete evacuation of pregnancy tissue in most patients, and serious complications are rare. As a primary approach, surgical evacuation results in faster and more predictable complete evacuation 22. The success of surgical uterine evacuation of early pregnancy loss approaches 99% 23. The largest U.S. trial reported that success rates after medical management of anembryonic gestations (81%) was lower than with embryonic or fetal death (88%) or incomplete or inevitable early pregnancy loss (93%) 23. However, a subsequent multivariable analysis of the same data revealed that only active bleeding and nulliparity were strong predictors of success 41. Therefore, medical management is a reasonable option for any pregnancy failure type.
The risk of infection after suction curettage for missed early pregnancy loss should be similar to that after suction curettage for induced abortion. Therefore, despite the lack of data, antibiotic prophylaxis also should be considered for patients with early pregnancy loss 44 45. The use of a single preoperative dose of doxycycline is recommended to prevent infection after surgical management of early pregnancy loss. Some experts have recommended administration of a single 200-mg dose of doxycycline 1 hour before surgical management of early pregnancy loss to prevent postoperative infection. The use of antibiotics based only on the diagnosis of incomplete early pregnancy loss has not been found to reduce infectious complications as long as unsafe induced abortion is not suspected 46. The benefit of antibiotic prophylaxis for the medical management of early pregnancy loss is unknown.
Although the risk of alloimmunization is low, the consequences can be significant, and administration of Rh D immune globulin should be considered in cases of early pregnancy loss, especially those that are later in the first trimester. If given, a dose of at least 50 micrograms should be administered. Because of the higher risk of alloimmunization, Rh D-negative women who have surgical management of early pregnancy loss should receive Rh D immune globulin prophylaxis 55.
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