Coumarins during pregnancy: Long-term effects on growth and development ofschool-age children

Anticoagulation during pregnancy is complicated because of potential risks for mother and foetus. Unfractionated or low-molecular-weight heparin is us ed for most anticoagulant indications. Its efficacy, however, in pregnant w omen with prosthetic heart valves is questioned, therefore coumarins are pr eferred for this indication. We studied long-term effects of prenatal coumarin-exposure on growth and on neurological, behavioural and cognitive development in 274 school-age chil dren in comparison with 231 age-matched nonexposed controls. No major abnor malities were found. The exposed children had an increased risk for minor n eurological dysfunction and for a low intelligence quotient (IQ below 80). The risk for a combination of two or more (minor) abnormalities was higher for the exposed children, RR = 7.6. We conclude that prenatal exposure to c oumarins is associated with an increased risk for disturbances in developme nt in school-age children. However, for the vast majority of children there is no clinical significant effect on growth and long-term development.