Risk of abnormal triple screen for Down syndrome is significantly higher in patients with female fetuses

The effect of fetal gender on the false-positive rate of Down syndrome by maternal serum screening

“…In a review of 110 000 pregnancies, our study showed that despite the differences in serum levels of MSAFP and MShCG in women carrying fetuses of different genders, the differences of screening false-positive rates between women with male or female fetuses were not significant. This is in contrast to the smaller studies by Spencer (2000) and Spong et al (1999), who both found that pregnancies with female fetuses were at increased risk for a false-positive screen result. Similar to that reported by Spencer (2000), a slightly increased female to male ratio with the increase of gestational weeks was noted for MShCG in our study.…”

“…In a retrospective review of 15 428 patients, Bazzett et al (1998) found that MSAFP was decreased in pregnancies of female fetuses at all gestational ages tested (14-22 weeks). Spong et al (1999) evaluated the triple screen among 977 women in the second trimester and found the MSAFP levels were decreased in women carrying female fetuses. In the largest study to date, Spencer (2000) evaluated 30 802 singleton normal pregnancies.…”

“…Recent literature, however, has suggested that there may be differences in the levels of analytes between the fetal genders. Several investigators have found that the levels of maternal serum AFP are lower in pregnant women carrying female fetuses (Sowers et al, 1983;Petrikovsky, 1989;Calvas et al, 1990;Lockwood et al, 1993;Bazzett et al, 1998;Spong et al, 1999;and Spencer, 2000). As well, several investigators have reported that maternal serum levels of hCG are higher in women carrying female fetuses (Leporrier et al, 1992;Bazzett et al, 1998;Spencer, 2000).…”

“…E-mail: muellevm@mcmaster.ca analytes produces more false positives in the presence of a female fetus has been raised by several investigators. Spong et al (1999) suggested that the relative risk of a false-positive with a female fetus was 1.5. Spencer (2000) suggested that women carrying female fetuses were 1.25 times more likely to be considered 'at increased risk' with this triple screening.…”

Nuchal translucency measurements in consecutive normal pregnancies. Is there a predisposition to increased levels?

“…It was suggested that there are additional factors, which may consistently influence the serum profile. For example, ethnic subgroups (Baumgarten, 1986;Wald et al, 1997;Thilaganathan et al, 1997) or fetal gender (Spong et al, 1999, Spencer, 2000bSpencer et al, 2000;Lam et al, 2001) were also found to have slight effect on maternal serum levels. Spencer et al (2001) studied a group of 149 pregnant women, and reported no correlation between fetal NTs from different pregnancies of the same women.…”