Fetal malpositions are abnormal positions of the vertex presentation of the fetal head (with the occiput as the reference point) relative to the maternal pelvis. Malpresentations are all presentations of the fetus other than vertex. As the baby reaches the final stages of pregnancy, it moves into position for delivery. If the mother is lying on her back, the most common and safest fetal malpresentation for the baby is:
- Facing downward
- Coming out headfirst
- Tucking its chin into its chest
- Folding its arms across the chest
- Angling its face and body to the right or left of the mother’s spine
There are many variations on this position, which are called malpresentation or abnormal presentations. Your doctor can sometimes correct the baby’s presentation, but in some cases, it’s safest to deliver via C-section. It is one of the commonest reasons for cesarean deliveries.
If the presentation is known beforehand, then delivery of the baby should be scheduled in a healthcare facility where surgical intervention, if indicated, can be performed. After 37 weeks of gestation when the woman is in early labor, external cephalic version can be attempted if vaginal delivery is deemed possible, if it is a single gestation, if membranes are intact, if the fetus has no growth retardation or anomalies, and there is no vaginal bleeding or history of a previous cesarean section.
Vaginal delivery can proceed if the external cephalic version is successful. If it is unsuccessful, then either a vaginal breech delivery should be attempted, or a cesarean delivery scheduled immediately.
A baby in a breech presentation is coming out bottom-first or feet-first. Breech babies can sometimes be cross-legged or have their feet reaching up toward their head. The doctor may be able to adjust the baby’s position before labor begins, by strategically pressing on the abdomen with ultrasound as a guide. This can be uncomfortable, so it is usually performed under regional anesthesia. If this doesn’t work, a Cesarean delivery may be recommended.
Babies exiting the womb head first, but facing up, toward the mother’s bellybutton, are in the occiput posterior position. Maternity care providers call this position “sunny side up.” Most of the time, uterine contractions or the mother’s pushing will rotate the baby to face down. If they don’t, the mother might experience longer labor, more back pains, and difficulty pushing the baby out.
In most pregnancies, the baby will end up with its spine vertical in the womb. Some, however, are lying horizontally, or “transverse lie,” in the womb. This transverse position makes vaginal delivery extremely unsafe. The doctor may try to adjust the baby’s positioning before labor, or recommend a Cesarean delivery.
When a baby’s hand or foot is presented alongside the baby’s head or bottom, this is called compound presentation. We can’t usually predict if the baby presents this way until the mother starts pushing. Luckily, compound presentation is not a cause for concern, and most babies presenting this way can continue on their way without issue.
Face Presentation/Brow Presentation
When the baby’s neck is outstretched, and its chin is pointing away from its chest, its face or brow will present first. This presentation, referred to as face presentation or brow presentation is fairly rare, but when it does happen, labor can take a little longer. Face presentation is diagnosed late in the first or second stage of labor by examination of a dilated cervix. The newborn’s face and head may be swollen or bruised for a few days. Most of the time, this presentation can be delivered vaginally, but occasionally a C-section is required.
Attempts to convert the face to a vertex or to rotate a posterior position by manual rotation to a more favorable anterior mentum position are rarely successful and are associated with complications, including cord prolapse, uterine rupture, and fetal cervical spine injury with neurological impairment. Given the availability and safety of cesarean delivery, internal rotation maneuvers are no longer justified unless cesarean section cannot be readily performed.
Shoulder dystocia occurs when the baby’s head has exited the birth canal, but its shoulders get stuck on the pelvic bone. It’s hard to predict when this may happen, but if it does, it is considered a medical emergency. These cases are associated with a shoulder presentation, high incidence of cord prolapse and consequent fetal compromise during labor so vaginal delivery is not attempted and cesarean section is highly recommended.
Your doctor may need to manually adjust the baby in order to free its shoulders. In the best-case scenario, the maneuvering works and the baby is delivered, vaginally and with no harm. Occasionally, the baby is injured in the process. It’s rare for a C-section to be performed in this case.