Variation in Length of the Estrous Cycle in Mice Due to Former Intrauterine Proximity to Male Fetuses1

Open Access
Publisher Website
Google Scholar
Abstract
Female mouse fetuses occupying an intrauterine position between male fetuses exhibit longer estrous cycles in adulthood than do females formerly residing in utero next to other female fetuses. This difference in adult cycle length was observed consistently when the two types of females were maintained under a variety of social conditions. Thus, these data suggest a fundamental biasing of the intrinsic timing of the estrous cycle by former intrauterine proximity to males in this and possibly other species in which more than one fetus is present in the uterus.