Low-lying placenta does not require a cesarean section, although there is a higher risk of emergency cesarean section.

Through the blood vessels in the umbilical cord, the fetus receives all the necessary nutrition, oxygen, and life support from the mother through the placenta. Waste products and carbon dioxide from the fetus are sent back through the umbilical cord and placenta to the mother’s circulation to be eliminated.

The primary function of the placenta in all species is to promote selective transport of nutrients and waste products between mother and fetus. Such transport is facilitated by the close approximation of maternal and fetal vascular systems within the placenta.

During pregnancy, the placenta is normally attached to the upper wall of the uterus. A placenta that forms low in the uterus without overlapping the cervical opening is referred to as a low-lying placenta. It is not a high-risk condition. It often gets better on its own as the pregnancy progresses.

If the placenta is still low in your womb, there’s a higher chance that you could bleed during your pregnancy or during your baby’s birth. This bleeding can be very heavy and put you and your baby at risk.

If the edge of your placenta is less than 20 mm from the entrance to the cervix on your scan at 36 weeks, a caesarean will be the safest way for you to give birth. If the placenta is further than 20 mm from your cervix you can choose to have a vaginal birth.

Conclusions: A low-lying placenta sonographically diagnosed in the second trimester typically resolves by the mid third trimester. Only rarely (1.6% of the time) does it persist to term or near term.

Low-lying placenta occurs when the placenta extends into the lower uterine segment and its edge lies too close to the internal os of the cervix, without covering it. The term is usually applied when the placental edge is within 0.5-5.0 cm of the internal cervical os 1.