Need for urgent delivery after third-trimester amniocentesis

To estimate the risk of need for urgent delivery after third-trimester amniocentesis as currently done using ultrasound guidance to assess fetal lung maturity.

Ultrasound records of women scheduled for third-trimester amniocenteses to assess fetal lung maturity from February 1990 through October 1997 were reviewed for possible complications during or immediately after procedures. Collected data included gestational age, indication for the procedure, number of needle passes, transplacental passage, needle gauge, and fluid color. The primary outcome examined was procedure-related complications that required emergency delivery or the decision to deliver before completion of maturity studies. Infants who developed hyaline membrane disease leading to neonatal intensive care admission were also identified.

During the 7 1/2-year study period, 962 amniocenteses were done to assess lung maturity. Complete data were not available for 49 cases. Of the remaining 913 procedures, 15 (1.6%) were unsuccessful (needle pass without collecting fluid). Forty-one infants were delivered spontaneously or by cesarean on the same day as the procedure. However, complications that required delivery were identified in only six cases, an incidence of 0.7% (95% confidence interval = 0.16, 1.24). Complications included fetal heart rate abnormalities (n = 3), placental bleeding (n = 1), abruptio placentae (n = 1), and uterine rupture (n = 1). Only one of six complications had a single needle pass with clear fluid collected. Hyaline membrane disease occurred in 14 neonates, including two with mature indices.

Although complications that required urgent delivery after third-trimester amniocentesis are rare, the risks of the procedure should be carefully weighed against the benefits.