Altered newborn gender distribution in patients with low mid-trimester maternal serum human chorionic gonadotropin (MShCG).

OBJECTIVE

to determine if the sex ratio (male/female) is altered in infants born to patients with low mid-trimester maternal serum human chorionic gonadotropin (MShCG).

STUDY DESIGN

Between 2/1/90 and 1/3/91, 3,116 patients underwent prenatal screening using second-trimester maternal serum alpha-fetoprotein (MSAFP), MShCG, and maternal serum unconjugated estriol (MSuE3). Among these, there were 132 patients with low second-trimester MShCG (< 0.4 MoM), normal MSAFP and MSuE3. The gender distribution of these term, normal newborns was compared to that of 237 controls, matched for race, maternal age, and referral source and delivered at term to mothers with normal mid-trimester MSAFP, MSuE3, and MShCG. The gender distribution of these two groups of newborns was also compared to that of 78 term newborns from the same obstetrical population delivered to mothers with second-trimester MShCG > 2.5 MoM and normal MSAFP and MSuE3. All patients had a complete obstetrical history.

RESULTS

Forty-nine percent of the controls were male vs. 62% of the group with slow second-trimester MShCG (P < .01). Within the group with low MShCG, 59% of infants were male when the MShCG was between 0.19 and 0.4 MoM (A) and 80% when the MShCG was < 0.2 MoM (B) (control vs. A vs. B P < .005). The sex ratio in the high-MShCG group was similar to control.

CONCLUSION

The data suggest that gender distribution is different from normal in patients with low mid-trimester MShCG.