Classification of threatened premature labor related to treatment with a prostaglandin inhibitor: indomethacin

The ductus arteriosus

The ductus arteriosus is a large vessel which connects the pulmonary trunk with the aorta. During fetal life it serves together with the foramen ovale as a shunt at cardiac level. Due to a complex regulatory mechanism it is capable of maintaining patency during fetal life and of rapid closure after birth. However, in premature neonates ductal patency frequently persists, an occurrence which may even be favourable in some situations. Recent investigations on the ductus arteriosus have provided new information about the regulatory mechanisms involved with its function. Initially, most studies on the fetal ductus arteriosus were conducted in animals. With the introduction of the combined use of two dimensional real-time and Doppler ultrasound systems the opportunity became available to study blood flow within the ductus arteriosus in the human fetus and neonate in a noninvasive manner. The increasing use in obstetric care of cyclo-oxygenase inhibitors for tocolysis and for prevention of the development of pregnancy induced hypertension and pre-eclampsia justifies the re-evaluation of the potential adverse effects of these drugs on the ductus arteriosus.

Patent ductus arteriosus after prolonged treatment with indomethacin during pregnancy: case report

Indomethacin was administered to suppress premature uterine contractions in a twin pregnancy from the 27th until the 32nd week of pregnancy. Patent ductus arteriosus was diagnosed after delivery in one twin and persisted patent for a period of 4 weeks. A hypothesis of the constrictive influence of prostaglandin synthetase inhibitors on the fetal ductus arteriosus during intrauterine and neonatal periods is suggested.

Treatment of premature labor contractions with combined ritodrine and indomethacine

The results of combined ritodrine and indomethacine treatment (RI) in premature labor contractions were compared with ritodrine alone (R). One hundred and twenty patients with threatened premature labor in weeks 26-34 were studied. Sixty RI women received 100 mg ritodrine in infusion followed by 60 mg daily orally until 35 weeks and indomethacine 200 mg on the first day of treatment only. The R group included 60 women with identical tocolysis indices, age of pregnancy and anamnestic parameters who received ritodrine only. The mean prolongation index (PI) was 18.2 in the RI group, against 11.5 in the R patients (P less than 0.05). The mean prolongation of pregnancy was 5.6 weeks in the first and 3.6 in the control group (P less than 0.05). Birthweight and Apgar scores were similar in the two groups. In order to examine the possible early closure of the ductus arteriosus due to the indomethacin therapy, echocardiograms were done on all newborn in the RI group: the pre-ejection period and right ventricular ejection time ratio was 0.19-0.26 after delivery and 0.17-0.22 1 month later, which excludes pulmonary diastolic hypertension due to premature closure of the duct. The combined RI treatment is more effective that R alone and does not give rise to any complications in the mother or the fetus.