Prenatal growth curves corrected for certain genetic and environmental factors

Factor analysis for non-orthogonal data was done to assess the straight and interaction effects of certain genetic and environmental factors on birth weight. While the interaction effects did not assume any significance, straight effects of gestational age, parity, mother's weight, and sex were significant in influencing the birth weight. Mother's height and socio-economic status of the family had no significant effect on birth weight. Step-up multiple regression analysis showed that contribution to the total variance explained (R2 x 100 = 29.7 per cent) in birth weight was about 15, 7, 5, and 2 per cent, respectively, from gestational age, parity, mother's weight, and sex of the baby. Correction of the mean weight curve was done by successive graphic approximation method and residuals were further minimized.