Tocolytic effectiveness of nifedipine versus ritodrine and follow-up of newborns: a randomised controlled trial

Several studies have demonstrated the superior tocolytic effectiveness of nifedipine over ritodrine. Only 1 trial conducted a long-term follow-up of newborns and found no difference in psychosocial and motor functioning. In a randomised, multicentre trial, we compared the tocolytic effectiveness of nifedipine and ritodrine and included a long-term follow-up of the newborns after 2 years of age.

Patients with imminent preterm labour were randomised and received either nifedipine or ritodrine. Side-effects, tocolytic effectiveness and neonatal outcome were studied. Development of the children was studied after the age of 2 years by a parental questionnaire.

Ninety-three patients were included. Birth was postponed for an average of 4.3 weeks in the ritodrine group and 5.0 weeks in the nifedipine group (p=0.4). Patients who received ritodrine experienced significantly more side-effects compared to patients who received nifedipine (29 versus 4%, p<0.05). No significant differences were found in either group for average birth weight, Apgar scores after 1 min, neonatal intensive care unit (NICU) admission and neonatal complications. Parental questionnaires after 2 years had a response rate of 70%. Two-thirds of the children had developed normally in both groups. In both groups, only a few children were severely retarded (n=4). No significant differences in development were found between the 2 groups.

Both nifedipine and ritodrine proved effective tocolytic drugs, however ritodrine caused significantly more maternal side-effects. Neonatal outcome and long-term development after 2 years of age were not significantly different. We favour nifedipine over ritodrine as a tocolytic drug.