Placenta previa is a condition that occurs during pregnancy when the placenta lies unusually low in the womb, partially or completely covering the cervix—the opening to the birth canal. This placement can pose risks during vagina delivery, but with early detection and proper care, most women go on to have healthy pregnancies.

What Is the Placenta?

The placenta is a vital organ that develops during pregnancy. It supplies oxygen and nutrients to the growing baby and removes waste products from the baby's blood. Normally, it attaches to the upper part of the womb. In placenta previa, however, it attaches too low.

Signs and Symptoms

• Painless vaginal bleeding in the second or third trimester
• Bright red blood, usually without cramps
• Bleeding may start suddenly and vary in amount

If you experience any of these symptoms, seek immediate medical attention.

Risk Factors

Some factors that increase the risk of placenta previa include:

• Previous cesarean delivery
• Multiple pregnancies
• Previous uterine surgery
• Smoking
• Maternal age over 35

Placenta previa is typically diagnosed during a second-trimester ultrasound scan, often at the routine anatomy scan performed between 18 and 20 weeks of gestation. However, it can also be suspected later in pregnancy if a woman experiences painless vaginal bleeding, usually in the second or third trimester.  

Management may include

• Limiting physical activity and avoiding sexual intercourse
• Monitoring with repesat ultrasounds
• Hospital admission for close monitoring

It's important to note that a low-lying placenta diagnosed early in the second trimester often resolves on its own as the uterus grows, a phenomenon known as placental migration. Therefore, a follow-up ultrasound is usually recommended around 28 to 32 weeks to reassess the placental position. Placenta previa that persists until the late third trimester or causes bleeding will require a Cesarean delivery, typically scheduled between 36 and 37 weeks if there are no other complications.

Conclusion

Placenta previa can sound alarming, but with the right monitoring and medical support, most women deliver healthy babies. Always attend your antenatal visits, routine scans and report any unusual symptoms promptly.