Subsequent Pregnancy Outcomes After Open Maternal-Fetal Surgery for Myelomeningocele

TLDR: Compared with delayed clamping, cord milking yielded similar effects on hematocrit concentrations, rates of necrotizing enterocolits, and intraventricular hemorrhage, and need for neonatal transfusions, and did not carry any increased risk of complications.

Abstract: B oth delayed clamping and milking of the umbilical cord have separately been shown to have positive effects for neonates. Delayed clamping improves neonatal anemia, lowers the need for transfusion, lowers the incidence of necrotizing enterocolitis, and decreases the incidence of intraventricular hemorrhage. While milking has also been associated with improved neonatal outcomes, there is a lack of studies comparing the 2 techniques. This study aimed to compare delayed clamping and umbilical cord milking in terms of effect on the initial hematocrit concentrations in preterm infants. This randomized controlled trial included singleton infants between 23 weeks 0 days gestation and 34 weeks 6 days gestation that were born at a single hospital between April 18, 2014, and June 5, 2018. Patients were excluded with known congenital anomalies, precipitous delivery, placental abruption, uterine rupture, or infants with risk factors for anemia. Patients were randomized to either the delayed cord clamping group or milking group using 1:1 block randomization. Delayed cord clamping lasted for 60 seconds and infants were held at the level of the maternal abdomen during cesarean delivery and at the perineum for vaginal delivery. For the milking group, the cord was milked 4 times before clamping, from ∼20 cm from the placental end of the cord to the infant’s umbilicus, with time for cord refill in between milking. An intent-to-treat approach was used in analysis. The sample size was calculated to create an 80% probability value of .05 for the primary outcome measure of a hematocrit difference of 3%. Of 282 patients who were randomized, 204 were included in the analysis. Of those, 100 were assigned to the milking group and 104 were assigned to the delayed clamping group. The milking procedure took, on average, 6 seconds. The cord clamping group had an average delayed cord clamping of 30 to 60 seconds. The clamping and milking groups were similar in terms of delivery mode, birth weight, cord blood arterial, and venous pH and Apgar scores. The median gestational age for delivery was 32 weeks. While there was a trend toward higher initial hematocrit concentration in the milking group compared with the delayed clamping group, this difference was not statistically significant (51.8 vs. 49.9; P=0.07). The 2 groups were similar in terms of transfusion (15.5% in the delayed clamping group vs. 9.1% in the milking group; P=0.24), intraventricular hemorrhage (delayed clamping group, 15.5% vs. milking group, 10.1%; P=0.35), and necrotizing enterocolitis (delayed clamping group, 5.8% vs. milking group, 3.0%; P=0.49). While the differences did not reach statistical significance, all these outcomes were lower in the milking group. Compared with delayed clamping, cord milking yielded similar effects on hematocrit concentrations, rates of necrotizing enterocolits, and intraventricular hemorrhage, and need for neonatal transfusions, and did not carry any increased risk of complications. There may be certain clinical situations where a 30to 60-second delay in cord clamping may delay necessary resuscitation by the neonatal team and milking the umbilical cord may be an acceptable alternative. These outcomes support the use of milking as a method for increasing infant blood volume. Subsequent Pregnancy Outcomes After Open Maternal-Fetal Surgery for Myelomeningocele