Sildenafil citrate and fetal outcome in pregnant rats.

OBJECTIVE

To determine the effects of sildenafil citrate on fetal growth in maternal rats exposed to hypoxia.

METHODS

Timed pregnant rats were randomized to either hypoxia or control on gestational days (GD) 18-20, and received either sildenafil (45 mg/kg) orally every 12 h on GD 18-21 or an equal volume of sterile water. Fetal pups were retrieved by laparotomy on GD 21. Pup weight and length were evaluated and cGMP measured in maternal and fetal blood.

RESULTS

In the non-hypoxic rats, sildenafil exposure was associated with a decrease in size(4.75 +/- 0.43 vs. 5.11 +/- 0.34 g, p = 0.00). In contrast, in the hypoxic rat model, sildenafil exposure was associated with increased size of the offspring (5.48 +/- 0.45 vs. 5.16 +/- 0.36 g, p = 0.016). Maternal cGMP levels were increased in the presence of both sildenafil and hypoxia (23.0 +/- 10.5 vs. 15.6 +/- 2.7 pmol/ml, p = 0.001).

CONCLUSION

Exposure to sildenafil in a non-hypoxic setting results in a decrease in fetal size. Sildenafil in the presence of a stimulus, hypoxia, will lead to increased fetal size. These results suggest that sildenafil may have some influence on fetal growth. How these effects occur and by what mechanism remain to be determined.