Placenta previa: symptoms and complications

Placenta previa is a condition in which this fundamental organ with multiple functions is positioned very low in the uterus and completely or partially covers the cervix (neck of the uterus).

Placenta previa occurs in about 1 in 200 pregnancies, and if it occurs early in pregnancy, it’s usually not a problem because the placenta can move upwards during pregnancy as the uterus grows. . There is talk of placenta previa after 28-30 weeks of pregnancy. 

Normally the placenta grows in the upper part of the uterus (see: placenta locations ), away from the cervix. During the last stage of delivery, called afterbirth , the placenta separates from the wall of the uterus and contractions help push it along the birth canal.

In placenta previa, when the cervix begins to flatten and dilate for labor, the blood vessels that connect the placenta to the uterus may tear. This can cause severe bleeding during delivery endangering the woman and the baby. This is why, in case of placenta in this low position, a cesarean delivery is planned.

What are the symptoms of placenta previa?

The most common symptom is painless bleeding from the vagina during the second half of pregnancy. Notify your doctor promptly if you experience vaginal bleeding at any time during your pregnancy. If the bleeding is severe, it is recommended to go to the hospital immediately.

Not all women with the placenta in this position have vaginal bleeding, in fact one third of women do not have this symptom.

How is placenta previa diagnosed?

It is diagnosed by abdominal or transvaginal ultrasound, particularly during the second trimester of pregnancy. When diagnosed in the second trimester of pregnancy, it resolves spontaneously in most cases, as the placenta moves upward in the following weeks in most pregnancies.

How is placenta previa managed?

Treatment depends on:

• gestational age in which the woman is
• severity of bleeding
• baby woman health

The goal is to prolong the pregnancy as much as possible.

Cesarean delivery is recommended for nearly all women with placenta previa to prevent severe bleeding.

If the woman is bleeding from placenta previa, she should be monitored closely in the hospital. Following checks by the doctors and if the tests show that the woman and her baby are doing well, they will try to prolong the pregnancy as much as possible, to favor the complete development of the baby.

If the bleeding is severe, your doctor may decide to give you blood transfusions. A hospital stay may also be required until the baby is born.

If you experience severe bleeding due to placenta previa at about 34 to 36 weeks of pregnancy, your doctor may recommend an immediate C-section.

At 36-37 weeks, your doctor may suggest an amniocentesis to test your amniotic fluid to see if your lungs are fully developed. If they are, an immediate C-section might be recommended to avoid future bleeding risks.

What are the causes of placenta previa?

The causes are not known, but the predisposing factors to have it are:

• Cigarette smoke
• Use of cocaine
• Age of the woman over 35 years
• Previous pregnancies
• Twin pregnancies
• Uterine surgery (including cesarean section)

If you had placenta previa in a previous pregnancy, what are the chances of it happening again?

There is a 2-3% chance that it will occur again in a new pregnancy (2 to 3%).

How can the risk of placenta previa be reduced?

There are no certain ways to prevent it. Surely it is good not to smoke and not abuse cocaine, things that in theory should be taken for granted in every pregnancy.

It is important to use a cesarean section only when strictly necessary, because this operation increases the chances of having placenta previa in subsequent pregnancies.