You may hear terms like position and station mentioned in the context of your baby’s delivery. Position refers to your baby’s placement in the uterus (left or right facing, headfirst or feet-first) and station refers to how far your baby’s head has moved into the pelvic cavity.
Between weeks 32 and 36 of pregnancy, your baby starts preparing for delivery by rotating to (ideally) a headfirst position or vertex presentation. Prior to this point your baby floated rather freely in the uterus, but their growing size sees them transition into a more fixed position for labor.
During this transition, instead of lowering into a headfirst position, some babies may lower their legs or pelvis to the exit from the uterus (presentation of the pelvis) or lie sideways in the uterus (transverse position). This is why your doctor monitors your baby’s position as your labor approaches. Babies can shift their position from pelvic to head, for example, over just a couple of days.
Another term used in relation to your baby’s delivery is “station”. One station is equivalent to one centimeter and during labor, the station increases as the baby’s head moves through the pelvis. Station 0 corresponds to midway through the pelvis and at +5 the baby’s head crowns and emerges from the vagina.