PATERNAL INFLUENCES ON BIRTH-WEIGHT

Objective. To assess the influence of paternal size on birthweight aft er suitable control for maternal and fetal factors. Design. Prospectiv e observational study. Setting. Delivery suite, City Hospital, Notting ham. Subjects. 571 husbands/partners of unselected women delivering Au gust 1992 to February 1993. Main outcome methods. Individualised birth weight ratio and thereby an adjusted birthweight for a typical mother. The results of a multiple regression analysis with the individualised birthweight ratio as the dependent variable. Results. When considered in isolation both paternal height and weight are significantly positi vely associated with crude and adjusted birthweight (p<0.01, analysis of variance). Due to correlations of paternal size with maternal size and smoking habit, only paternal height is significant in the multiple regression analysis (p=0.01). Conclusion. If the partner of an averag e woman is short (mean-2s.d.) then the baby will be 183 g lighter than if he is tall (mean+2s.d.). This effect of paternal height on birthwe ight must be genetic and therefore should be taken into account when d efining intra-uterine growth retardation and macrosomia.