Offspring sex and pregnancy outcome by length of gestation
LJ Vatten, R Skjærven - Early human development, 2004 - Elsevier
Background: It takes a higher number of male than female embryos to produce a live born
infant. The unbalanced pregnancy survival by offspring sex may also be reflected in higher
proportion of preterm male births, and in unbalanced sex distribution in certain pregnancy
conditions, such as preeclampsia. Methods: We used data from the Medical Birth Registry of
Norway, a population-based registry that has recorded births since 1967. For this study, we
used information on offspring sex and length of gestation that was available for 1,691,053 …
infant. The unbalanced pregnancy survival by offspring sex may also be reflected in higher
proportion of preterm male births, and in unbalanced sex distribution in certain pregnancy
conditions, such as preeclampsia. Methods: We used data from the Medical Birth Registry of
Norway, a population-based registry that has recorded births since 1967. For this study, we
used information on offspring sex and length of gestation that was available for 1,691,053 …