Does cord presentation on ultrasound predict cord prolapse?

To study the association of umbilical cord presentation found on antenatal ultrasound and the incidence of cord prolapse in labor.

We reviewed the antenatal records of all deliveries in the Mount Sinai Hospital in a 5-year period and conducted two separate retrospective studies. In the first study we reviewed the antenatal sonograms of all women with proven cord prolapse for cord presentation (study A). In the second study we reviewed the obstetrical outcome of pregnancies where sonographic cord presentation was identified in the third trimester of pregnancy (study B).

In study A, 16,551 delivery records were reviewed and 42 patients were found to have had clinical cord prolapse (0.25%). Sonograms were available for 16 of these 42 patients. Only 2 of them (12.5%) had cord presentation on ultrasound scan. In study B, cord presentation was reported in 13 of 8,122 consecutive sonograms (0.16%). Six of these patients (6/13, 46%) had been scanned once. Three required cesarean delivery for malpresentation and cord presentation on ultrasound (3/13, 23%), while the other 3 had uncomplicated vaginal deliveries (23%). The remaining 7 patients had repeat scans which revealed persistent cord presentation in 3 (23%). All 3 underwent cesarean delivery, 1 following cord prolapse. The other 4 spontaneously converted to vertex with resolution of cord presentation as proven at delivery (31%).

Cord presentation and cord prolapse are not synonymous. Documented cord presentation during the third trimester necessitates repeat scans and intrapartum sonographic assessment to determine the mode of delivery.