What is Sunny Side Up Birth?

By on June 21, 2023

On this episode of the Healthful Woman’s podcast, OB-GYN and maternal-fetal medicine specialist Dr. Nathan Fox answers a question about occiput posterior birth from one of our listeners. Occiput posterior position (OP) is also referred to as sunny-side-up delivery or face-up delivery. Here’s what you need to know about this atypical form of delivery and how your child can still be safely delivered.

How Are Babies Normally Delivered?

When you look at your head, you’ll notice that it’s actually an oval, not a circle. The length from the forehead to the back of the head is longer than the width of the head from ear to ear. When a baby is being delivered, it’s easier for the narrow part of the head to fit through the space between the mother’s pelvic bones (the inlet). This inlet is also shaped like an oval, but the longer or wider part is going left to right, not front to back.

Dr. Fox creates a helpful picture of how a baby is delivered and says to “think of it as diving down into the mother’s pelvis.” As the baby dives forward, their head will typically face either the left or the right so that it aligns with the wide part of the oval-shaped pelvic opening. However, this changes as the baby exits the pelvis through the outlet. The outlet is wider from up to down so the baby has to do a 90-degree internal rotation. Most of the time, the baby’s head rotates with its chin facing the floor (occiput anterior).

Why Does the Position Matter?

During this rotation, the doctor and nurses delivering the baby will use terms “like three o’clock or nine o’clock and then it’s [going to] rotate hopefully from three o’clock to 12 o’clock. So if the back of the head is at 12 o’clock, the front of the head is facing six o’clock or the floor” (Dr. Fox). This helps them assess the progress of the labor. If the head is rotating properly, they can predict that the delivery will proceed normally. Knowing how the head is positioned also keeps the baby safe in case forceps or a vacuum are needed to help with the delivery.

If the baby’s head is facing upward, it can be more difficult to deliver considering the shape of the pelvis and the head. It’s also more difficult to flex the head and maneuver the baby since the chin will hit the chest more easily. Delivery might take longer because more time is needed to safely navigate the head out, but OP babies can still be safely delivered if these factors are considered. An operative vaginal delivery with forceps or the use of manual rotation in which the doctor manually guides and rotates the head can help the delivery go more smoothly. If those methods don’t work or the delivery is taking too long, a C-section might be needed to ensure the baby’s safety.

How Common is Sunny Side Up Delivery?

Only 5% of children are born in the occiput posterior position (face-up). This type of delivery is also more common during a woman’s first birth and for women who are older or weigh more. Larger babies and later gestational ages can also increase the likelihood of an OP birth. Newer studies have also discovered an interesting correlation between having an epidural and a sunny-side delivery. Although it’s unclear exactly why this occurs, “possibly it’s because it sort of relaxes the pelvic muscles and potentially that tightness of the pelvic muscles is part of the reason the baby’s head sort of like twists in normally into the pelvis, does that rotation” (Dr. Fox). However, this is just a theory.

How Are Mothers Affected by Sunny-Side-Up Delivery?

During labor, some women with a face-up baby report feeling more contractions in their back than in the front. This is called back labor and it might occur because the baby’s spine is pushing more toward the mother’s back. However, this is not predictable and will not happen for every mother. After a successful vaginal face-up delivery, women may be more at risk of larger tears and higher blood loss. This is because the wider part of the baby’s head is pushing through the narrower part of the outlet.

Contact Us Today

To learn more about OP delivery, check out the Healthful Woman podcast or call our office to get in touch with Dr. Fox and our team of maternal-fetal experts. We will be happy to answer any questions you might have to ease your worries and create a pregnancy and delivery plan that is as safe and comfortable as possible.

Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!

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