1 Department of Pediatrics, University of Southern California School of Medicine and the Los Angeles County-University of Southern California Medical Center
FSH and LH-HCG concentrations were determined by radio-immunoassay in paired maternal and cord sera. The sera of 50 mothers and 51 infants, 25 female and 26 male (one set of twins), were assayed.
Mean (± SD) FSH concentration of mothers (3.4 ± 0.9 mIU/ml) giving birth to female infants was not different, p>0.1, from that of mothers (3.7 ± 0.7 mIU/ml) giving birth to male infants. In contrast, mean (± SD) LH-HCG concentration of mothers (15.99 ± 3.1 IU/ml) giving birth to female infants was significantly, p<0.005, greater than that of mothers (11.37 ± 5.0 IU/ml) giving birth to male infants.
Cord serum FSH mean (± SD) concentration was significantly, p<0.005, greater in female infants (3.7 ± 0.5 mIU/ml) than male infants (2.4 ± 0.8 mIU/ml). However, mean (± SD) LH-HCG concentrations in female infants (0.122 ± 0.015 IU/ml) was significantly, p<0.005, less than that of male infants (0.156 ± 0.040 IU/ml).
Poor correlation, on an individual basis and on a statistical basis, between maternal and cord serum FSH and LH-HCG concentrations was observed.
The data of this investigation are consistent with fetal pituitary gonadotropin secretion, confirm previous observations that women bearing a female fetus have higher LH-HCG concentrations than those bearing a male fetus, and suggest a sex difference in cord serum gonadotropin concentrations.
Submitted on April 20, 1973