Management of Second Pregnancy After One Second Trimester Abortion
Recommended Approach: Serial Ultrasound Surveillance (Option D)
For a patient with one prior second trimester loss, serial transvaginal ultrasound to assess cervical length and dilation is the recommended management strategy, not prophylactic cerclage at 13 or 18 weeks. 1
Why Not Prophylactic Cerclage at 13 Weeks (Option A)
History-indicated cerclage requires three or more prior second trimester losses or preterm births due to painless cervical dilation, or classic features of cervical insufficiency - a single second trimester loss does not meet these criteria 1
The Society for Maternal-Fetal Medicine specifically reserves history-indicated cerclage for individuals with classic historical features of cervical insufficiency or an unexplained second-trimester loss in the absence of placental abruption 1
Inappropriate cerclage placement carries significant risks - cerclage after previable PPROM was associated with dramatically increased odds of preterm birth in subsequent pregnancies (63.2% vs 10.9%; OR 14.0) 1
Why Not Cerclage at 18 Weeks (Option B)
Prophylactic cerclage at any gestational age is not indicated without meeting the criteria for history-indicated cerclage (≥3 losses) or ultrasound-indicated cerclage (short cervix on surveillance) 1
Waiting until 18 weeks for prophylactic placement misses the opportunity for proper surveillance-based decision making 1
The Correct Strategy: Serial Ultrasound Surveillance
Surveillance Protocol
Begin transvaginal ultrasound cervical length screening at 16-18 weeks gestation 1
Continue screening every 1-2 weeks until 24 weeks gestation 1
Transvaginal ultrasound is highly reproducible and identifies changes at the internal os where preterm birth risk first manifests 1
Intervention Thresholds
Cervical length <25mm is the threshold for intervention consideration 1
When short cervix is detected, ultrasound-indicated cerclage reduces preterm birth by 30% before 35 weeks in high-risk patients 1
Treatment Options When Short Cervix Detected
If cervical length falls below 25mm during surveillance, three evidence-based interventions are available:
Ultrasound-indicated cerclage (30% reduction in preterm birth before 35 weeks) 1
Vaginal progesterone supplementation starting at 16-24 weeks (44% reduction in PTB <34 weeks) 1
Cervical pessary (78% reduction in PTB <34 weeks) 1
The decision between these interventions should incorporate the specific cervical length measurement, presence of funneling, and the patient's specific history 1
Additional Management Components
Provide counseling about warning signs of preterm labor and cervical insufficiency at the initial visit 1
Ensure access to maternal-fetal medicine consultation if cervical changes are detected during surveillance 1
Offer vaginal progesterone supplementation starting at 16-24 weeks if cervical shortening develops 1
Common Pitfalls to Avoid
Do not place prophylactic cerclage based solely on one prior second trimester loss - this represents overtreatment and exposes the patient to unnecessary procedural risks 1
Do not delay surveillance until 18 weeks - screening should begin at 16-18 weeks to allow adequate time for intervention if needed 1
Do not rely on clinical assessment alone (Option C) - digital cervical examination is poorly predictive compared to transvaginal ultrasound cervical length measurement 1
Do not assume all second trimester losses are due to cervical insufficiency - other etiologies include placental abruption, infection, and fetal anomalies that would not benefit from cerclage 1