If the placenta partially or entirely blocks the regular vaginal delivery route, a doctor may refer to this as placenta previa.
The placenta is an organ that develops inside the uterus during pregnancy. It provides oxygen and nutrients to the developing fetus.
Placenta previa affects around 3–5 births out of every 1,000. Below, learn about the types, symptoms, and risks of this issue and how doctors identify it.
Doctors classify placenta previa according to the position of the placenta. The four main
A low-lying placenta is between
A marginal placenta borders the opening but does not obstruct it. The edge of the placenta is within
This is the
Partial placenta previa often resolves on its own during pregnancy. If it does not, it may still be possible to deliver vaginally.
When a doctor identifies placenta previa early in pregnancy, it can help them have a better understanding of the risks involved and whether a cesarean will be necessary.
A healthcare provider can spot placenta previa during a routine
If a woman believes that she has placenta previa, due to vaginal bleeding. she should undergo an ultrasound, then possibly a
An ultrasound of the abdomen can show a doctor whether it will be safe to perform an ultrasound of the vagina, called a transvaginal ultrasound.
During a transvaginal ultrasound, the healthcare provider or technician places the ultrasound tool within the vagina. This can give a better idea of where the placenta is
Experts have identified transvaginal ultrasound as the best method of identifying the type of placenta previa.
- are over 35 years old
- are carrying multiple babies
- have given birth before
- have had uterine surgery before, such as a cesarean delivery or the removal of uterine fibroids
- have what doctors call abnormal placental development
- smoke tobacco
- use cocaine
Placenta previa can be dangerous for the woman and the developing baby. Experts have found, for example, that early delivery early after placenta previa may
However, the position of the placenta
If placenta previa does not resolve, it can increase the risk of:
- complications to fetal growth
- bleeding — during the pregnancy, the delivery, or the period that immediately follows
- premature delivery
placenta accreta, which involves the placenta growing into the wall of the uterus
- damage to nearby organs
- the need for the removal of the uterus, in 0.2% of placenta previa cases
People sometimes confuse placenta previa with
|Placenta previa||Placental abruption|
|Signs||are not so obvious from the start||develop quickly, with high intensity|
|Bleeding||is visible||is both internal and visible|
|Symptoms, such as shock or anemia||are proportionate to visible blood loss||are intense, compared with visible blood loss|
|Pain||is often not present||is present|
The placenta may realign, resolving the previa, within 32–35 weeks of pregnancy, when the lower part of the uterus thins and stretches out.
If placenta previa does not resolve on its own, a cesarean delivery becomes necessary.
The operation is usually booked for
A woman can reduce any vaginal bleeding by resting in bed and avoiding
Some types of vaginal examination can induce or worsen bleeding in a woman with placenta previa, so the entire healthcare team should be aware of the issue.
There are no ways to prevent placenta previa.
If placenta previa causes heavy bleeding, the fetus may not be receiving enough blood, which can lead to further
In pregnancies with placenta previa, there is a higher chance of premature delivery and low birth weight.
In addition, placenta previa is the
Placenta previa involves the placenta covering the opening of the uterus into the cervix. This obstruction may be partial or complete.
The placenta’s position can determine whether a woman will need to undergo cesarean delivery.
The main risk of placenta previa involves blood loss. It can lead to various complications, some of which can be life threatening.
If any vaginal bleeding occurs during pregnancy, it is important to consult a healthcare provider.