What is the best management approach for a pregnant woman with a history of second-trimester abortion in her first pregnancy to prevent preterm birth in her second pregnancy?

Management of Second Pregnancy After Prior Second-Trimester Abortion

Serial ultrasound monitoring of cervical length (Option D) is the recommended approach, with progesterone supplementation as the primary intervention, rather than routine cerclage placement. 1, 2

Why Cerclage Should NOT Be Routinely Placed

History-indicated cerclage should be reserved only for classic features of cervical insufficiency or unexplained second-trimester loss in the absence of placental abruption. 3 A single second-trimester abortion does not automatically qualify as cervical insufficiency requiring cerclage. 1

Evidence Against Routine Cerclage:

• Cerclage placement after previous preterm premature rupture of membranes was associated with increased odds of preterm birth (OR 14.0; 95% CI 3.97-49.35), demonstrating potential harm rather than benefit. 3, 2
• The Society for Maternal-Fetal Medicine explicitly recommends following guidelines for previous spontaneous preterm birth management rather than automatic cerclage placement (GRADE 1C recommendation). 3

Recommended Management Strategy

Primary Intervention - Progesterone Supplementation:

• Progesterone supplementation is the cornerstone intervention for preventing recurrent preterm birth in patients with prior spontaneous preterm birth history. 2
• This represents the only intervention with Grade 1C recommendation from ACOG for this clinical scenario. 2
• Progesterone should be initiated based on standard preterm birth prevention protocols. 1, 2

Surveillance Protocol:

• Serial transvaginal ultrasound cervical length assessments should begin at 16-24 weeks gestation. 2
• This allows for identification of cervical shortening that might warrant ultrasound-indicated cerclage if cervical length becomes critically short. 2

Patient Education:

• Daily self-monitoring for vaginal discharge, bleeding, contractions, and pelvic pressure is essential. 2

Risk Counseling

Nearly 50% of subsequent pregnancies after periviable preterm premature rupture of membranes result in recurrent preterm birth, with 30% occurring at <34 weeks. 1, 2 This high recurrence risk justifies close surveillance but not prophylactic cerclage. 1

Critical Pitfall to Avoid

Do not place prophylactic cerclage at 13 weeks (Option A) or 18 weeks (Option B) based solely on one prior second-trimester loss. 1 This approach may actually increase preterm birth risk and does not align with current evidence-based guidelines. 3, 2 Cerclage should only be considered if serial ultrasound demonstrates progressive cervical shortening or if the patient has classic cervical insufficiency features (painless cervical dilation, multiple prior losses). 3