What is the management of a patient presenting with threatened abortion?

Management of Threatened Abortion

Transvaginal ultrasonography is the diagnostic method of choice to confirm fetal viability and rule out ectopic pregnancy, followed by expectant management with activity modification for viable pregnancies, while all Rh-negative women require 50 μg anti-D immunoglobulin administration. 1

Initial Diagnostic Evaluation

Ultrasound Assessment

• Perform transvaginal ultrasonography immediately to confirm intrauterine pregnancy, assess fetal viability (cardiac activity), and detect subchorionic hematoma. 1
• Do not delay ultrasound imaging based on β-hCG levels below a discriminatory threshold, as ectopic pregnancies can present at almost any β-hCG level and rupture has been documented at very low levels. 1
• The ultrasound must differentiate threatened abortion from other causes including ectopic pregnancy, ovarian torsion, and pelvic inflammatory disease. 1

Clinical Examination

• A complete pelvic examination with speculum visualization is indicated to identify the source of bleeding and assess cervical status (closed cervix confirms threatened abortion versus open cervix indicating inevitable abortion). 1
• Evaluate for signs of infection including maternal tachycardia, purulent cervical discharge, and uterine tenderness, as clinical symptoms may be subtle in early pregnancy. 2

Management Based on Fetal Viability

If Fetus is Viable (Cardiac Activity Present)

Expectant Management Protocol:

• Recommend bed rest until 48 hours after cessation of bleeding. 3
• Prescribe folic acid supplementation throughout pregnancy. 3
• Consider uterine sedatives and progesterone supplementation, particularly if luteal phase deficiency is suspected, continuing hormonal treatment until 28 weeks of gestation. 4, 3
• Serial ultrasound examinations should be performed to assess fetal growth and development. 1

Prognostic Factors:

• Approximately 75-80% of threatened abortions with viable fetuses will continue to term with appropriate management. 3, 5
• The presence of subchorionic hematoma, particularly if >20 cm², is associated with higher spontaneous abortion rates (up to 42.9% of threatened abortion cases have subchorionic hematoma). 3
• Only 11-17% of patients with threatened abortion will progress to spontaneous abortion during initial hospitalization. 3

If Fetal Demise is Confirmed

Diagnostic Criteria for Early Pregnancy Loss:

• Crown-rump length ≥7 mm without cardiac activity. 2
• Mean gestational sac diameter ≥25 mm without visible embryo. 2
• Absence of embryo ≥14 days after initial gestational sac visualization. 2

Management Options:

• Surgical evacuation (vacuum aspiration) is preferred and has the lowest complication rates: hemorrhage 9.1%, infection 1.3%, retained tissue 1.3%. 2
• Medical management with misoprostol 600-800 mcg vaginally has a 91.5% success rate in first trimester but carries higher bleeding and infection risks. 2, 6
• Expectant management is absolutely contraindicated in missed abortion due to increased risk of intrauterine infection, coagulopathy, and maternal sepsis. 2

Rh Immunoglobulin Prophylaxis

Critical Requirement for All Rh-Negative Women

Definitive Recommendation:

• Administer 50 μg of anti-D immunoglobulin to all Rh-negative women with documented first-trimester pregnancy loss (complete or incomplete abortion). 7, 1, 2
• Fetomaternal hemorrhage occurs in 32-48% of threatened abortion cases, with 11% showing positive Kleihauer-Betke tests. 1, 8

Nuanced Guidance for Threatened Abortion with Viable Fetus:

• The American College of Obstetricians and Gynecologists states there is no evidence-based recommendation for anti-D immunoglobulin in threatened abortion when a live embryo/fetus is present, and many physicians do not treat in this scenario. 1
• However, it may be prudent to administer anti-D immunoglobulin when there is heavy bleeding, associated abdominal pain, or when the event occurs near 12 weeks' gestation. 7
• Given the 11% incidence of fetomaternal hemorrhage in threatened abortion and the catastrophic consequences of Rh alloimmunization, administration of 50 μg anti-D immunoglobulin is reasonable even with a viable fetus, particularly if bleeding is more than spotting. 7, 8

Complications and Follow-Up

Increased Pregnancy Risks

• Threatened abortion is associated with increased incidence of antepartum hemorrhage (7.5%), preterm labor, intrauterine growth retardation (13.2%), and preterm premature rupture of membranes (5.66%). 3, 9
• These pregnancies require careful obstetric supervision throughout gestation with serial growth assessments. 9

Contraceptive Counseling Post-Loss

• Provide immediate contraceptive counseling if pregnancy loss occurs, as ovulation can resume within 2-4 weeks. 6
• Combined hormonal contraceptives or implants can be initiated immediately after complete abortion without waiting for next menses. 6
• If starting contraception within 7 days of abortion, no backup contraception is needed. 6

Psychological Support

• Women are at increased risk for significant depression and anxiety for up to one year after spontaneous abortion. 5
• Counseling should address feelings of guilt, the grief process, and coping strategies. 5

Critical Pitfalls to Avoid

• Never delay ultrasound waiting for β-hCG to reach a "discriminatory threshold"—ectopic pregnancy can rupture at very low β-hCG levels. 1
• Do not wait for fever to diagnose intrauterine infection—look for subtle signs like maternal tachycardia and uterine tenderness. 2
• Never choose expectant management for confirmed missed abortion—this significantly increases maternal morbidity (60.2% vs 33.0% with active management). 2
• Do not forget Rh immunoglobulin prophylaxis—failure to provide it can cause alloimmunization affecting all future pregnancies. 2, 6