Chorioamniotic membrane separation following open fetal surgery: pregnancy outcome.

OBJECTIVE

To review the incidence of posthysterotomy chorioamniotic membrane separation and delivery outcome following open fetal surgery [myelomeningocele (MMC); cystic adenomatoid malformation (CCAM); congenital diaphragmatic hernia (CDH); sacrococcygeal teratoma (SCT)].

STUDY DESIGN

Retrospective review of a maternal population undergoing open fetal surgery at a single tertiary level program (1998-2001) following the initiation of close postoperative ultrasound follow-up for membrane separation. Onset of membrane separation was coded as not present (NP), immediate (<2 weeks) or delayed (>2 weeks) from day of surgery.

RESULTS

Fifty-three charts were reviewed: MMC 43, CCAM 7, CDH 1, and SCT 2. In the MMC group there were 26 NP, 8 immediate, and 9 delayed. Preterm labor occurred in 4 patients with only 2 having had membrane separation. Risk of membrane separation is increased for surgery done at less than 23 weeks gestation (p < 0.005). Delay from MMC surgery to delivery was 11.0, 9.8, 12.0 weeks for NP, immediate, and delay, respectively. In the MMC group, there were 3 neonatal deaths (NND) at 9, 9, and 21 days post surgery (PROM/PTL; chorioamnionitis, PROM/PTL, respectively). No membrane separation was present in the CCAM, CDH, and SCT cases.

CONCLUSIONS

(1) Membrane separation was significantly more likely to occur if surgery was performed prior to 23 weeks. (2) Membrane separation post hysterotomy (17/50 = 34%) may be associated with an increased risk of PROM but not delivery before 30 weeks gestation. (3) Delivery prior to 33 weeks gestation for MMC groups was 12/43 (28%) with 3 NND (7%). (4) Elective delivery at 36-37 weeks gestation was possible for 43% of the fetal surgery population.