Modified cervical cerclage in pregnant women with advanced bulging membranes: knee-chest positioning

Emergent cervical cerclage is often unsuccessful in patients with severely protruding fetal membranes for the following reasons: (1) difficulty in pushing the bulging membranes into the cervix; (2) risk of premature rupture of membranes during the operative procedures; and (3) displacement of the cerclage tape by the shortened cervix.

We performed Shirodkar's cervical cerclage with a slight modification. Using a metreurynter, a primary suture was made with the patient placed in the knee-chest position; a Shirodkar's cerclage was then performed in the dorsal lithotomy position.

Since 1992, we have performed this procedure on five patients whose fetal membranes bulged into the vagina, at a gestational period of 20-24 weeks. When a patient was placed in the knee-chest position, the bulging membranes intruded spontaneously into the uterine cavity, but the procedure did not cause the membranes to rupture in any patient. The procedure prolonged the pregnancy to longer than 36 gestational weeks in two of the five patients. Three infants survived intact.

Our promising experience warrants further studies on the advantages of the knee-chest position during the application of cervical cerclage in pregnant women who present with fetal membranes that bulge through a widely dilated cervix.