Fetal echocardiography during indomethacin treatment.

Fetal echocardiograms were evaluated in 315 studies performed in 107 fetuses exposed to indomethacin. In the majority of cases, the results of the fetal echocardiography study were within normal limits (74%). The most common abnormal phenomena were tricuspid valve regurgitation (10%), ductal constriction (6%), tricuspid valve regurgitation and ductal constriction (5%), an increased ductal velocity (2%), and other (3%). The difference between the prevalence of ductal constriction in the whole series of studies (11%) compared to the prevalence of ductal constriction per fetus (25%) (p < 0.001) suggests that this phenomenon was only temporary and disappeared when medication was discontinued. The mean gestational age for detection of tricuspid valve regurgitation was 27.7 +/- 2.8 weeks and for ductal constriction, 30.9 +/- 2.1 weeks (t-test, p < 0.01). Trivial tricuspid valve regurgitation was detected at a mean of 26.7 +/- 2.2 weeks and significant tricuspid valve regurgitation at 29.6 +/- 2.3 weeks (t-test, p < 0.01). We conclude that indomethacin treatment is relatively safe for the fetal heart. The most common side-effects are tricuspid valve regurgitation and ductal constriction. Tricuspid valve regurgitation may be detected before ductal constriction, but by itself it is not a contraindication for the continued use of indomethacin.