Pregnancy outcomes for mouse preimplantation embryos exposed in vitro to the estrogenic pesticide o,p′-DDT

Pregnancy outcomes were evaluated following uterine transfer of murine preimplantation embryos exposed in vitro to the estrogenic pesticide o,p′-dichlorodiphenyltrichloroethane (o,p′-DDT). Single-cell embryos were incubated 72 h in medium droplets containing 0.1% ethanol (control) or 0.1 μg/ml o,p′-DDT (pesticide). Morula and preblastocyst embryos were transferred in groups of eight to right uterine horns of pseudopregnant mice (n = 111) and pups (n = 132) were evaluated at Caesarean-section (C-section). In vitro exposure to o,p′-DDT reduced development to morula (P < 0.001) and modestly increased blastomere apoptosis (P = 0.05). However, treatment differences were not detected for implantation rates (35% versus 39%; P = 0.64), pup numbers per dam (2.3 versus 1.9; P = 0.36), transfer efficiencies (16% versus 14%; P = 0.53), fetal weights (1.56 g versus 1.57 g; P = 0.91), skeletal abnormalities (55% versus 66%; P = 0.47), or male ratios (54.8% versus 53.8%; P = 1.0). In vitro exposure of preimplantation embryos to 0.1 μg/ml o,p′-DDT for 72 h resulted in no measurable effects on subsequent implantation or pup characteristics at C-section.