Correct Answer: C. Prolapse of membranes into the vagina
Cervical cerclage is a surgical intervention to reinforce an incompetent cervix and prevent preterm delivery in the second trimester. However, it has absolute contraindications that must be respected to avoid catastrophic maternal and fetal complications. Prolapse of membranes into the vagina is an absolute contraindication because it indicates that the gestational sac or fetal membranes have already herniated through the cervix into the vaginal canal. Placing a cerclage in this scenario would trap infected or compromised membranes above the stitch, creating a closed space prone to ascending infection, chorioamnionitis, and sepsis. Additionally, the membranes are already at risk of rupture, and mechanical manipulation during cerclage placement can precipitate PROM. The presence of membrane prolapse signals that the cervix has already lost its structural integrity beyond the point where cerclage can be salvageable. According to Indian obstetric guidelines and standard protocols (FOGSI recommendations), once membranes prolapse, expectant management or termination becomes the appropriate counselling, not surgical intervention. The risk of maternal sepsis and fetal loss far outweighs any theoretical benefit of cerclage in this setting.
Why the other options are wrong
A. Advanced maternal age — Advanced maternal age (≥35 years) is NOT a contraindication to cervical cerclage. While advanced age increases obstetric risks (gestational diabetes, hypertension, chromosomal abnormalities), it does not preclude cerclage if cervical insufficiency is present. The indication for cerclage depends on cervical findings and obstetric history, not maternal age alone. This is a distractor that confuses general obstetric risk factors with specific contraindications to the procedure. B. Fetal fibronectin positive — Fetal fibronectin (fFN) positivity indicates increased risk of preterm delivery but is NOT an absolute contraindication to cerclage. In fact, fFN testing is used to risk-stratify patients with cervical insufficiency. A positive fFN in the context of a short cervix may actually strengthen the indication for cerclage rather than contraindicate it. The presence of fFN reflects ongoing cervical remodelling, not membrane prolapse or infection, so cerclage remains a valid option. D. Ruptured membranes — While ruptured membranes (PROM) are a relative contraindication and generally warrant against cerclage due to infection risk, they are not listed as an absolute contraindication in the same category as membrane prolapse. PROM alone may be managed expectantly in some cases, whereas membrane prolapse into the vagina represents irreversible cervical failure and active herniation—a more definitive contraindication. This option is a trap for students who conflate PROM with prolapse.
High-Yield Facts
- Membrane prolapse into vagina is an absolute contraindication to cerclage—indicates irreversible cervical failure and risk of chorioamnionitis.
- Cervical cerclage indications: singleton pregnancy, 16–24 weeks, cervical length <25 mm on transvaginal ultrasound, or history of preterm birth with cervical insufficiency.
- Relative contraindications to cerclage: active vaginal infection, PROM, vaginal bleeding, fetal anomalies incompatible with life, and intrauterine fetal death.
- Cervical length 15 mm at 18 weeks is severely shortened and warrants urgent assessment; cerclage may be offered if membranes are intact and no infection is present.
- Transabdominal cerclage may be considered if transvaginal cerclage is contraindicated due to extreme cervical shortening or previous failed cerclage.
Mnemonics
CERCLAGE CONTRAINDICATIONS (Absolute) Membrane prolapse, Infection/chorioamnionitis, Choice (fetal anomaly incompatible with life), Active bleeding, Germ positive (PROM with signs of infection), Early rupture of membranes (with prolapse). Focus: Prolapse = trapped infected membranes = sepsis risk. PROLAPSE vs PROM Memory Hook Prolapse = Protrusion (membranes bulging into vagina—STOP, don't cerclage). PROM = Rupture (fluid leaking, membranes intact structurally—relative contraindication, case-by-case). Prolapse is the red flag that cervix has failed.
NBE Trap
NBE pairs "ruptured membranes" (option D) with "prolapse of membranes" (option C) to trap students who conflate PROM with prolapse. While both are concerning, only prolapse represents an absolute contraindication because it indicates active herniation and irreversible cervical failure, whereas PROM alone may be managed expectantly in selected cases.
Clinical Pearl
In Indian tertiary centres, a dilated cervix with membrane prolapse at 18 weeks is often managed with immediate hospitalization, antibiotics, and counselling for expectant management or termination rather than cerclage—because the risk of ascending infection and sepsis in a resource-limited setting is unacceptably high. Cerclage in this scenario would be iatrogenic harm.
_Reference: DC Dutta's Textbook of Obstetrics (8th ed.), Ch. 23 "Cervical Incompetence"; FOGSI Guidelines on Preterm Birth Prevention; Harrison Ch. 346 "Preterm Labor"_