PATERNAL INFLUENCES ON BIRTH-WEIGHT

Objective. To assess the influence of paternal size on birthweight after suitable control for maternal and fetal factors. Design. Prospective observational study. Setting. Delivery suite, City Hospital, Nottingham. Subjects. 571 husbands/partners of unselected women delivering August 1992 to February 1993. Main outcome methods. Individualised birthweight 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 positively 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 average 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 birthweight must be genetic and therefore should be taken into account when defining intra-uterine growth retardation and macrosomia.