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Objective: To assess the success rate and effects on maternal and fetal outcomes of nifedipine administered as a tocolytic agent to women in threatened preterm labour.
Methods: During 1st January to 31st October, 2007, a total of 53 pregnant women with threatened preterm labour between 20-36 weeks participated in this study. All women were inhibited contraction with nifedipine 20 mg. orally every 30 minutes for 3 times then maintenance with nifedipine SR 20 mg. every 12 hours until 34 weeks. If a neonatal intensive care unit was not available, the inhibition of labour was prolonged until 36 weeks of gestation. If there is any complication with nifedipine, the inhibition of contraction was changed to be bricanyl intravenous form. If there were contraindications to the use of bricanyl, magnesium sulphate was used.
Results: 53 pregnant women with threatened preterm labour participated. The gestational age ranged from 28 to 35 weeks with the mean of 31.6 weeks of gestation. Failure of inhibition with nifedipine was found in 30/53 cases (57%) with a complication of maternal hypotension (90/60 mmHg) for 7 cases (13%) and one case of fetal distress. 23/53 (43%) cases were successful to inhibit contraction with nifedipine. Those patients who failed to inhibit contraction with nifedipine, 28 cases continued to inhibit contraction with bricanyl and 2 with magnesium sulphate (due to placenta previa). All were later successful to stop contraction with bricanyl and meagnesium sulphate. Ten pregnant women underwent caesarean section, 31 cases of normal delivery, 3 cases of vacuum extraction, and 2 cases referred to other hospitals (normal delivery). Seven cases were not delivered. The gestational age at delivery ranged from 29 to 40 weeks of gestation with the mean gestational age of 37.7 weeks. The babiesâ€™ weights ranged from 1,690 to 4,090 grams with the average body weight of 2,742 grams.
Conclusion: Nifedipine cannot be used successfully to inhibit contraction in threatened preterm labour. Other medications can be tried to minimize the incidence of preterm labour.
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