Relationship of paternal factors to birth weight.

OBJECTIVE

To investigate the relationship between paternal characteristics and birth weight.

STUDY DESIGN

A total of 241 gravidas with uncomplicated, singleton, term pregnancies were studied. Maternal demographic and pregnancy-specific characteristics were used to calculate the expected birth weight for each fetus using a previously validated birth weight prediction equation. The additional independent predictive value of 4 paternal variables was assessed using multiple regression.

RESULTS

Before adjustment for other variables, paternal height and weight significantly correlated with birth weight, but paternal age and body mass index did not. After controlling for maternal and pregnancy-specific factors that are known to influence fetal weight, only paternal height was significant as a predictive variable. The proportion of variance in birth weight that could be independently explained by paternal height was 2%. A 10-g gain in fetal weight was associated with each centimeter of increase in paternal height (P < .02). Using the resulting combination equation that included paternal height as a variable, 31% of the variance in term birth weight could be explained, and birth weights could be accurately predicted to within +/- 8.3% (+/- 288 g). Fathers with heights 2 SD above and below the mean had the term birth weight of their offspring increased and diminished by 125 g, respectively.

CONCLUSION

Paternal height explains an independent portion of the variance in term birth weight among normal newborns of up to 250 g that cannot be explained by other maternal or pregnancy-specific factors. Paternal age, weight and body mass index do not independently influence birth weight.