Abstract
So far no information is available as to whether a relationship exists between the concentration on the maternal plasma oestrogens and the birth weight of the newborn and its sex. Using a gaschroma-tographic method (5) the maternal plasma concentrations of oestriol, oestrone and 17β-oestradiol were measured in normal pregnancies. From their values the regression line for each oestrogen was calculated in the individual case. the hormone value on the regression line corresponding to the 40th week of pregnancy is correlated to the birth weight and the sex of the infant. the series comprises 20 normal pregnant women delivering 20 normal infants with birth weights ranging between 2700-4100 g. As far as oestriol is concerned the series include a further 10 pregnancies, where nine of the babies born were small for dates. the correlation between plasma oestriol and birth weight is not statistically significant (0.10 > P >0.05). the relationship of plasma oestrone and 17β-oestradiol to birth weight is far from being significantly correlated. Concerning the sex of the infants, the mean values of plasma oestriol and 17β-oestradiol of 10 women with female fetuses do not differ from the mean values of 10 women with male fetuses. the mean value of plasma oestrone in the first group, however, is twice the value in the second group, yet the difference is not statistically significant (0.10 > P > 0.05).