AT THE PREGNANCY MEETING
SAN DIEGO (FRONTLINE MEDICAL NEWS) – Nifedipine and atosiban for tocolysis in women with threatened preterm delivery had similar rates of adverse perinatal outcomes in a randomized clinical trial, but an increase in perinatal mortality in those treated with nifedipine is raising concerns about its safety.
The rate of the composite primary outcome of perinatal death, bronchopulmonary dysplasia, culture-proven sepsis, intraventricular hemorrhage worse than stage II, periventricular leukomalacia worse than stage I, and necrotizing enterocolitis worse than stage I was 14.2% among the 248 women randomized to receive nifedipine. Similarly, it was 15.1% in the 254 women randomized to receive atosiban in the multicenter Assessment of Perinatal Outcome After Specific Tocolysis in Early Labor ( APOSTEL III trial ), Dr. Elvira Vliet reported at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine.
There also was no difference between the nifedipine and atosiban groups on a number of secondary outcomes, including prolongation of pregnancy (6 days and 4 days, respectively) and the percentage of patients undelivered at 48 hours after randomization (66% and 69%, respectively). No cases of maternal mortality occurred.
But the rate of perinatal mortality was 5.4% in the nifedipine group vs. 2.1% in the atosiban group for a relative risk of 2.567, said Dr. Vliet of University Medical Center Utrecht, the Netherlands. Two of the perinatal deaths in the nifedipine group and one in the atosiban group were associated with congenital abnormalities, she noted.
Study participants were women with either a singleton or twin pregnancy between the 25th and 34th week of gestation who presented to one of 19 perinatal or large teaching hospitals with symptoms of threatened preterm delivery. Treatment with nifedipine or atosiban was given for 48 hours.
The groups did not differ with respect to baseline characteristics such as maternal age, body mass index, previous preterm birth, and gestational age.
The current findings suggest that most perinatal outcomes are similar in patients treated with either nifedipine or atosiban, but the higher perinatal death rate in the nifedipine group requires further in-depth analysis, Dr. Vliet said.
Dr. Vliet reported having no financial disclosures.
