Impact of antenatal selective serotonin reuptake inhibitor exposure on pregnancy outcomes in mice

OBJECTIVE: This study investigates fluoxetine (FLX) exposure as an etiology for altered gestational length and adverse pregnancy outcomes. STUDY DESIGN: Two experiments were performed exposing mice to drinking water (H2O) or H2O + FLX. Primary outcomes included gestational length, litter size, and live birth rate. In experiment 1, time-mated dams were monitored for spontaneous birth, and gestational length was calculated. In experiment 2, dams were dissected on day 14 to verify litter size and qualities of embryo implantation. RESULTS: There was no difference in gestational length between H2O dams (480.7 +/- 13.2 hours) and H2O +/- FLX dams (483.5 +/- 10.1 hours), P = .70. Mean litter size was decreased in H2O + FLX dams (4.1 +/- 1.3/litter) compared to H2O dams (5.5 +/- 1.9/litter), P = .04. H2O + FLX dams were less likely to have live births (25.4%) compared to H2O dams (49.3%), P = .01. CONCLUSION: Antenatal FLX exposure did not statistically alter gestational length, but did affect litter size and spontaneous loss in mice. This warrants further investigation.