Your baby moves around extensively in the womb, and he’ll settle into final position late in your pregnancy, according to Laura Riley, M.D, an OB-GYN in New York City. But not all baby positions are suitable for birth, and sometimes intervention is needed to correct presentation for delivery. Here’s everything you need to know about baby positions in the womb.
Vertex position (also called cephalic or anterior position) is ideal for delivery. Your baby’s head is down near the birth canal, and she’s facing your back. This head-first position allows the cervix to stretch, making it easier to deliver the rest of your baby’s body.
So when does Baby go head down, since she’s constantly moving around in the womb? According to Dr. Riley, most babies instinctively settle themselves this way between 32 and 36 weeks of pregnancy.
The posterior position (or occiput posterior position) means that the baby is face-up, or "sunny side up," instead of face-down, so the hardest part of her head rests near your lower back instead of your belly. Essentially the mother and baby are back-to-back. This position often results in a longer labor, since the head has to rotate further during labor in order to be born. It can also cause intense back pain during labor for Mom.
Fortunately, only about 8 percent of babies are still posterior when it’s time to push, especially if an early epidural is avoided, says George Mussalli, M.D., director of MaternalFetal Medicine at Bronx-Lebanon Hospital Center, in New York City. If your baby doesn't turn around, your doctor might try to rotate the baby manually. And if that doesn't work—and your labor goes on for too long and starts to pose a threat to your baby's health—your doctor may decide to do a C-section.
About 4% of full-term babies are in breech presentation, when the butt or feet are positioned near the cervix. A breech presentation can raise the risk of injury to your baby for several reasons. First, the baby’s foot or bottom could tangle in the umbilical cord, causing life-threatening issues like umbilical cord prolapse. It’s also possible that your baby’s smaller body parts (feet, legs, body) might slide down the cervix before its fully dilated, causing the head to get stuck in the birth canal.
Doctors may try to correct your baby’s position with a “version” (external cephalic version). For a version, the doctor or midwife repositions the baby by pushing on the mom’s abdomen and the baby’s head, says Dr. Riley. The procedure is successful about half of the time.
What if your breech baby fails to turn to the proper vertex position? While it’s not always necessary, research shows that it’s safer for a breech baby to be delivered by cesarean section.
Transverse Lie Position
In a transverse lie position, your baby is lying across your uterus horizontally, rather than the standard vertical way. This position increases the likelihood that a shoulder will come through the birth canal first. It’s rare that a fetus is positioned this way close to delivery. If this does happen, though, doctors will need to perform a C-section to prevent umbilical cord prolapse (when the umbilical cord is delivered before the baby).
How to Tell If Baby Is Head Down
So how can you tell if your little one is in the proper position for delivery? Your doctor will feel your abdomen with her hands during prenatal visits. A suspected breech or posterior position can be confirmed through ultrasound.
You might also determine your baby’s position through fetal movements. For example, babies in a posterior position will kick the front middle portion of the abdomen, and your belly might look flattened. In breech position, you might feel kicks around your belly button, if his legs are down (you may feel more normal kicks around your ribs if his legs are up). What’s more, you might gauge a hard bulge near your ribs; this is your baby’s head, and his entire body should move if you gently press on it.