Coumarin derivatives are preferred anticoagulants for management of patients with mechanical heart valves, however fetal exposure in the first trimester of pregnancy is known to cause birth defects. We report a case and review the medical literature with respect to long-term follow-up of growth and cognition of individuals exposed to coumarin derivatives in utero. BJ was born at 37 weeks to an 18-year old mother whose pregnancy was complicated by coumadin therapy. His mother had congenital heart disease with mitral regurgitation, which required mechanical valve replacement and long-term anticoagulation therapy. She sought prenatal care 6 weeks after her last menstrual period, and was switched to heparin. The cardiologist was concerned about the presence of a potential clot, therefore coumadin was restarted at 11 weeks, 3 days. Pregnancy was otherwise uncomplicated with frequent prenatal ultrasounds, which demonstrated normal growth and nasal hypoplasia on fetal face profile. There was no evidence of joint echodensities suggestive of epiphyseal stippling. At birth he was noted to have characteristic nasal hypoplasia, noisy breathing, and congestion after oral feeds. A skeletal survey demonstrated epiphyseal stippling in the knees, proximal femurs, lower spine and glenoid fossa. He had mild nail hypoplasia of the fingers and 5th toes, and was otherwise neurologically normal. This fetus was exposed to coumadin from the time of conception to an estimated 3 weeks and 5 days post-conception, and he was re-exposed from 9 weeks and 3 days estimated post-conception to birth. The window of risk is considered between the 6th and 12th week of gestation, but this child demonstrates coumarin embryopathy while adhering to the standard recommendation for anticoagulation therapy. In reviewing reports on long-term follow-up of fetuses exposed to coumarin derivatives for counseling purposes, it is remarkable that there are few cohorts described in the medical literature. Pregnancy loss is relatively high and the risk for developing the embryopathy is approximately 5%. In small series, growth tends to be well-preserved and cognition is not significantly different from a non-exposed matched cohort. In the embryopathy group, primary concerns relate to the degree of nasal hypoplasia and meatal stenosis. Even though the coumarin embryopathy is clearly recognized in obstetric and cardiology practices, information on outcomes in prospectively acquired cohorts is lacking.