Fetal cardiac function and ductus arteriosus during indomethacin and sulindac therapy for threatened preterm labor: a...

The purpose of this randomized study was to evaluate the effects of indomethacin (10 patients) and sulindac (10 patients) given for 4-days on the fetal cardiac function and ductus arteriosus in pregnancies complicated by threatened premature labor between 28 and 32 gestational weeks.

By use of pulsed color Doppler techniques the pulsatility index in fetal ductus arteriosus was calculated. Peak systolic velocities in the fetal ascending aorta and pulmonary trunk were also measured. By M-mode echocardiography both ventricular inner end-diastolic and end-systolic diameters were measured and ventricular fractional shortenings were calculated. Tricuspid valve regurgitation was evaluated by pulsed and color Doppler techniques. The ultrasonic examinations were made before and 4, 24, 48, and 72 hours after the start and 24 hours after the end of medication.

Indomethacin significantly decreased the mean pulsatility index in fetal ductus arteriosus 4 hours after the beginning of medication. This decrease became greater later during medication, and it was associated with a significant increase in both ventricular inner end-diastolic diameters and with a significant decrease in right ventricular fractional shortening. The mean pulsatility index in the fetal ductus arteriosus increased to control values at 24 hours after the end of medication. Sulindac significantly decreased the mean pulsatility index in fetal ductus arteriosus only 24 hours after the beginning of medication. All other mean pulsatility index values did not differ from control values. Other cardiac parameters remained unchanged during sulindac treatment.

Indomethacin has a significant reversible constrictive effect on the fetal ductus arteriosus that is associated with secondary changes, especially in the right ventricle. Sulindac seems to have only a mild and transient constrictive effect on the fetal ductus arteriosus.