A posterior baby, or occiput posterior (OP) presentation, occurs when a baby is positioned head-down in the uterus, but the back of their head faces the mother’s spine instead of her belly. The baby’s face looks forward, often described as “sunny-side up” or “stargazer.” While many babies start labor this way, it can lead to a longer or more challenging birth.
Understanding Posterior Presentation
When a baby is in the occiput posterior position, their head is not optimally aligned for navigating the curved birth canal. The baby’s head, with chin extended, may present its widest part first, making passage through the pelvis more difficult. This increases pressure on the mother’s tailbone and spine.
Common signs include intense, persistent lower back pain, often called “back labor,” which may continue between contractions. Other indications are irregular or less effective contractions, or slower labor progression. Some mothers might notice a flatter abdomen or feel the baby’s kicks primarily in the front. During a cervical examination, a healthcare provider might feel the baby’s anterior fontanelle, the larger soft spot on the top of the head, indicating the baby’s face is oriented towards the mother’s front.
Techniques to Encourage Fetal Rotation
Mothers can use non-medical techniques to encourage a baby to rotate from a posterior to an anterior position, aiming to create more pelvic space and ease labor. Consistent practice can be beneficial, though results are not guaranteed.
Pelvic tilts, performed on hands and knees, involve gently rocking the pelvis forward and backward. This motion helps loosen the lower back and encourages pelvic movement, providing space for the baby to shift. Many find this exercise comforting and helpful for alleviating back strain.
Forward-leaning inversions involve kneeling on a raised surface, like a couch or stairs, and slowly lowering the upper body to rest on forearms on the floor, allowing hips to be higher than the head. This technique uses gravity to lengthen the uterus and its ligaments, potentially creating more room for the baby to reposition. Perform this with caution and assistance, especially in later pregnancy.
Side-lying release helps balance pelvic muscles and ligaments. It involves lying on one side with the upper leg hanging off a bed or couch, allowing gravity to gently open the pelvis and release tension. This can address asymmetrical tightness contributing to a posterior presentation.
Remaining active and moving regularly supports optimal fetal positioning. Walking encourages the baby to descend and rotate with gravity. Avoid prolonged reclining, especially on soft couches or recliners that tilt the pelvis backward, as these can encourage a posterior lie. Instead, opt for upright positions, sitting on a birth ball, or a chair with knees lower than hips to promote a forward pelvic tilt.
Complementary methods like acupressure and massage can also offer support. Certain acupressure points, such as Spleen 6 (SP6) or Urinary Bladder 67 (UB67), are thought to encourage fetal rotation. Therapeutic massage, focusing on releasing tension in the pelvic and abdominal areas, can help create space for the baby to move. These should be performed by a professional or with proper guidance.
Medical Interventions for Posterior Presentation
When self-help techniques are insufficient or a healthcare provider deems it necessary, medical interventions can encourage fetal rotation. These approaches involve professional oversight and can be employed in late pregnancy or during labor.
External Cephalic Version (ECV), typically performed by an obstetrician, involves manually manipulating the baby from outside the mother’s abdomen to encourage a head-down, anterior position. ECV is usually attempted after 36 or 37 weeks, with success rates varying (often 50-60%). Potential risks, though uncommon, include transient fetal heart rate changes, premature rupture of membranes, placental abruption, or, rarely, the need for an emergency cesarean section.
Chiropractic care, specifically the Webster Technique, offers a non-invasive approach. It focuses on balancing the mother’s pelvis and reducing tension in the uterine ligaments. This technique does not directly turn the baby but aims to create an optimal environment and sufficient space for the baby to naturally move into a more favorable position.
Acupuncture and moxibustion are alternative therapies. Moxibustion involves burning a dried herb (mugwort) near specific acupressure points to stimulate and warm them. This is believed to encourage fetal movement and rotation. These methods are typically initiated between 33 and 37 weeks, when the baby has adequate room to change position.
Labor and Delivery with a Posterior Baby
Even if a baby remains posterior as labor progresses, various strategies can help manage the process and facilitate delivery. Many babies (approximately 90%) rotate to an anterior or more favorable position spontaneously or with coaxing during labor. If the baby remains posterior, however, labor may be longer and more intense.
Positional changes during labor are effective in encouraging rotation and alleviating discomfort. Hands-and-knees positions can help widen the pelvis and reduce spinal pressure, sometimes allowing the baby to turn. Leaning forward over a birth ball or chair, and side-lying positions, also create more pelvic space and encourage fetal movement. Walking and gentle movement throughout early labor can harness gravity to assist the baby’s descent and rotation.
Pain management is a significant consideration with a posterior baby, due to the increased likelihood of back labor. Counter-pressure applied to the lower back or sacrum by a support person can provide relief by easing tension and relaxing pelvic muscles. Warm compresses or hydrotherapy, such as a shower or bath, can also soothe persistent back pain. Epidural analgesia is an option, but be aware it might relax pelvic floor muscles, potentially affecting the baby’s ability to rotate.
If the baby does not rotate naturally or with positional changes, and labor stalls, medical interventions for delivery may become necessary. Forceps or vacuum extraction might assist the baby’s rotation and delivery through the vaginal canal. While these assisted deliveries can be successful, a persistent posterior position increases the likelihood of a cesarean section, particularly if the baby cannot rotate or labor fails to progress safely.