Placenta Previa

Definition - What does Placenta Previa mean?

Placenta previa is a low-lying placenta attached to the cervix (the exit from the uterus). About one in 200 pregnancies usually experience placenta previa. The abnormal placenta carries an inherent risk of tearing the blood vessels that connect the placenta to the uterus. This can cause massive bleeding during labor, delivery, and even after delivery.

Given the risk of excessive bleeding, placenta previa can cause unfavorable effects (as serious as death) in both the mother and baby. Moreover, the uncontrolled bleeding from placenta previa may also call for a hysterectomy (the surgical removal of the uterus) thus leaving the woman infertile.

FertilitySmarts explains Placenta Previa

In the majority of pregnancies, the placenta attaches to the top or the side walls of the uterus. However, this pregnancy-specific organ may sometimes abnormally implant in the lower segment of the uterus, covering the mother's cervix marginally or completely.

Placenta previa is more common in females who:

  • Are age 35 years or older
  • Are carrying more than one baby
  • Have had a cesarean section(s) in the past cause scars on the uterus (the rising rates of cesarean deliveries is one of the factors that largely contribute to the increasing cases of placenta previa)
  • Had D&C (dilation and curettage)
  • Have had two or more children in the past
  • Had placenta previa in an earlier pregnancy
  • Smoke or use cocaine during pregnancy

Most cases are diagnosed early on in pregnancy via ultrasound. The rest may manifest as an emergency vaginal bleeding without pain in the second or third trimester of pregnancy. Some women might bleed throughout the pregnancy and during the delivery. The bleeding often ceases spontaneously and then recurs with labor.

Placenta previa prevents a safe vaginal delivery and instead, warrants delivery via cesarean section. Severe bleeding can occur during c-section while separating the placenta. In this case, hysterectomy becomes necessary along with other measures like a blood transfusion. Inability to do so could otherwise result in death due to massive blood loss. Excessive bleeding may also occur after the delivery, called postpartum hemorrhage. This also requires urgent attention and intervention similar to the bleeding during delivery.

A study shows that women with placenta previa located in the front (anterior placentas) have poorer outcomes and are more likely to bleed massively and undergo hysterectomy compared to any other placental location.

Women with placenta previa are likely to lose their fertility potential due to the removal of the uterus.

The baby is also at increased risk of complications like premature birth, lower birth weight, and difficulty breathing due to collapsed airways (a condition called respiratory distress syndrome).

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