Intact amniotic membranes may serve to protect the extremely preterm infant from some of the mechanical forces exerted upon it and its umbilical cord by the process of vaginal birth. The purpose of this study was to determine if there is a difference in the short term neonatal outcome of extremely preterm infants with or without rupture of membranes (ROM) at time of delivery.
We performed a retrospective cohort study of all extremely preterm vaginal births at two tertiary care centers over a ten year period. Extremely preterm infants were defined as gestational age 24 0/7 to 26 6/7, and birth weight less than 1000g. Exclusion criteria were multiple gestation, aneuploidy, and delivery by c-section. Data from maternal and neonatal records was analyzed using Fisher's exact and student's t-test. Regression models were used to compare demographics between groups.
A total of 209 infants met inclusion criteria (161 vertex and 48 breech). Outcomes for vertex and breech presenting infants were analyzed separately. Twenty-four percent of the vertex infants were born en caul and 74% had early ROM. The vertex/en caul group had a higher mean arterial cord pH (7.33 vs 7.30, p<0.001) than the vertex/early ROM group. Apgar scores, neonatal morbidity, and neonatal mortality were not significantly different between the vertex/en caul and vertex/early ROM groups. In the breech group, 42% were born en caul and 58% had early ROM. The breech/en caul group had higher 5 minute Apgar scores when compared to the breech/early ROM group (6 vs 4, p=0.02). Mean arterial cord pH was also higher in the breech/en caul group than the breech/early ROM group (7.32 vs 7.25, p=<0.001). Neonatal morbidity and mortality were not significantly different between the breech/en caul and breech/early ROM groups.
The en caul method of delivery is associated with significantly higher arterial cord pH values in extremely preterm infants. Unless a clear indication for artificial rupture of membranes exists, clinicians should attempt to deliver these infants en caul.
© 2006 Mosby, Inc. Published by Elsevier Inc. All rights reserved.