During pregnancy, the fetus moves around into different fetal positions, but most end up in the optimal head down, face down (cephalic occiput anterior) position in the last few weeks. When the fetus doesn’t move into the cephalic position for birth, it’s called fetal malpresentation.
One of the rarest positions is the transverse lie, where the fetus lies horizontally, often with one shoulder down or pressing against the birth canal. If you have a transverse baby at term, your provider will intervene because a vaginal delivery is not possible from this position.
Here’s all you need to know about transverse lie causes and how it may affect pregnancy and delivery.
What Does Transverse Lie Mean?
The transverse lie position is when the fetus lies across the pregnant person’s abdomen horizontally. Because the shoulder is often in the pelvic inlet, it is also sometimes called shoulder presentation. But the fetus can also have its back facing the birth canal or with feet and hands facing it.
The chances of the baby being in the sideways position at term are only around 1 in 300. But before term, at 32 weeks gestation, it’s as high as 1 in 50.
“Transverse lie is normal in the first trimester, common in the second, unusual in the third, and it’s not a position where vaginal birth is possible,” says Gail Tully, CPM, creator of Spinning Babies, a website that offers ways to ease a baby’s rotation through the pelvis based on its position.
Causes of a Transverse Lie Position
The reason that a full-term baby is in a transverse lie position is often unknown, but there are some things that make it more likely. “Two of the most common risk factors for transverse lie at term include having extra amniotic fluid—often associated with diabetes but can be found on its own—and multiple gestation, such as twins or triplets,” says Layan Alrahmani, MD, maternal and fetal medicine specialist and assistant professor in obstetrics and gynecology at Loyola University Medical Center.
Other Possible Risk Factors for a Transverse Baby
Other possible risk factors for transverse lie at term include:
- Multiparity (previous pregnancies may lead to lax abdominal muscles)
- Premature labor
- Low amniotic fluid
- Placenta previa (the placenta is covering the pregnant person’s cervix)
- Pelvic, uterine, or fetal abnormalities (the latter is more common in primiparity, or first time births)
“Sometimes the baby is in the position for a reason,” says Karolyn Zambrotta, CNM, an obstetrics and gynecology specialist. “And after the doctor does the C-section you’ll find the problem, like a short or tight umbilical cord.”
Possible Risks and Complications
Transverse lie at term can be risky for both the pregnant person and baby.
“The transverse lie is frequently found early in the pregnancy. But if the baby does not change position, then a vaginal delivery cannot occur and we have to plan differently,” says Carolina Bibbo, MD, maternal-fetal medicine specialist at Brigham and Women’s Hospital.
“If the water were to break when the baby is in a transverse lie position, the cord could prolapse which is an obstetrical emergency.”
Possible Complications of a Transverse Baby
Possible complications of the transverse lie position include:
- Birth defects
- Birth trauma
- Infection
- Obstructed labor
- Postpartum hemorrhage
- Umbilical cord prolapse
- Uterine rupture
- Stillbirth
How a Transverse Baby Affects Pregnancy
Some pregnant people feel abdominal and back pain during pregnancy when the fetus is in the sideways position. This is related to the uterus being stretched in different ways and can cause tightening in the ribs and cramping lungs. If your health care provider approves, you can try deep breathing and gentle yoga exercises at home to help relieve pain and encourage the fetus to turn.
How a Transverse Baby Affects Delivery
If your health care provider still suspects the fetus is lying horizontal at 36 weeks, they'll order an ultrasound to confirm. Because a baby in the transverse lie position cannot be delivered vaginally, your providers will develop an alternatebirth plan which can include a procedure called external cephalic version (ECV) to try and turn the fetus for vaginal delivery or a planned C-section.
In the case of multiples, triplets are almost always delivered via C-section. But for twins, if the first is head down, the second may drop into the cephalic position for normal delivery having more room after the first one comes out. “You could also try ECV or internal podalic version (IPV) on the second twin if needed,” says Dr. Alrahmani. “It’s really case by case and depends on the provider’s experience and preference, too.”
Can You Turn a Transverse Baby?
After 34 weeks, it is very unlikely for a transverse baby to spontaneously move into the optimal head-down position for delivery. But, in some cases, it is possible to turn a transverse baby before labor.
Natural methods
If the fetus is not head down by 32 weeks, and there are no health concerns, midwives like Zambrotta might first recommend trying some natural techniques. As Dr. Bibbo notes, the data is limited for different approaches but certain yoga positions can help in some cases.
Low-risk methods to encourage transverse babies to turn include:
- Sound or light (putting music or a bright light near the bottom of the uterus)
- Temperature (placing something cold like frozen peas behind the head and something warm like a rice-filled sock at the bottom of the stomach)
- Traditional Chinese medicine (TCM) like moxibustion, which involves heating acupuncture points with a stick of mugwort
Small studies have shown that the Webster technique, a gentle chiropractic approach that aligns the pelvis, can help correct fetal malpresentation. And the forward-leaning inversion, also developed by a chiropractor, is the most effective position for encouraging transverse lie babies to turn, according to Tully, who trains labor and delivery nurses on body balance techniques.
Always speak with your health care professional before trying any methods to turn the fetus.
Medical intervention
If natural methods have not helped turn a transverse baby by 36 weeks, your provider will likely want to try an ECV in which they use their hands to put pressure on your belly to try and turn the fetus head down. This procedure should be done in a hospital setting to monitor the fetal heart rate, and for the rare case where an emergency C-section is needed.
Possible complications include placental abruption, fetal heart rate abnormalities (FHR), premature rupture of the membranes, preterm labor, fetal distress, and vaginal bleeding.
ECV may not be safe if you have placenta previa, low amniotic fluid, a significant uterine abnormality, vaginal bleeding, high blood pressure, multiples (before delivery of the first twin), or fetal distress.
“In general, the success rate for external cephalic version is 60% of babies,” explains Dr. Bibbo. “But there’s a greater chance for ECV to turn a fetus in transverse lie than in a breech position.”
C-section
A baby in the transverse lie position cannot fit through the pregnant person’s pelvis. If gentle exercises, chiropractic techniques, or other natural methods don’t help your baby turn by 36 weeks, you may be a candidate for ECV to move the baby into the optimal head-down position for birth. But if ECV doesn’t work, then the health care provider will schedule a C-section.
