Aberrant endocrinology and ovarian response to clomiphene citrate during the course of an undiagnosed early intrauterine pregnancy: a case report.

This is an unusual case of embryonic exposure to clomiphene citrate (CC) in the setting of an undiagnosed early pregnancy with successful follicular response to CC and progression of pregnancy despite markedly attenuated serum progesterone and estradiol levels and a thin endometrium. A review of literature on the potential of CC for teratogenicity is presented. A 36-year-old woman underwent 2 ovulation inductions (OIs) with CC. Successful pregnancy followed the second OI cycle. Fetal measurements on transvaginal ultrasound identified the pregnancy to be chronologically advanced and consistent with the first OI treatment cycle. The follicular response to CC during the second OI cycle in the setting of ongoing early pregnancy, and pregnancy progression despite markedly attenuated endometrium, low serum levels of serum progesterone, and estradiol and embryonic exposure to CC, are notable. The possibility of inadvertent embryonic exposure to fertility drugs in the event of undiagnosed early pregnancy must be considered in infertile patients pursuing repeat treatment cycles. Serum beta-hCG testing should be considered before repeat treatments.