Wednesday, 2 July 2014

Placenta Previa


What Is Placenta Previa?

The placenta is the organ created during pregnancy to nourish the fetus, remove its waste, and produce hormones for your pregnancy. The placenta is attached to the wall of the uterus by blood vessels that supply the fetus with oxygen and nutrition and remove waste from the fetus and transfer it to the mother.

The fetus is attached to the placenta by the umbilical cord. Through the cord, the fetus receives nourishment and oxygen and removes waste. On one side of the placenta, the mother's blood circulates, and on the other side, fetal blood circulates. The mother's blood and fetal blood usually don't mix in the placenta.

The placenta is usually attached to the upper part of the uterus, away from the cervix, the opening which the baby passes through during delivery. On rare occasions, the placenta lies low in the uterus, partly or completely blocking the cervix, a condition called placenta previa.

Placenta previa is frequently seen in pregnancies before the 20th week but usually resolves in most cases, leaving only 10% that persist into later pregnancy. As the uterus grows, the placenta usually moves higher in the uterus, away from the cervix. But if it remains near the cervix as your due date nears, which happens in about 1 in 200 pregnancies, you're at risk for bleeding, especially during labor as the cervix thins and opens. This can cause major blood loss in the mother. For this reason, women with a placenta previa usually deliver their babies before their due date by cesarean delivery.

There are several types of placenta previa:

A low-lying placenta is near the cervical opening but not covering it. It will often move upward in the uterus as your due date approaches.
A partial placenta previa covers part of the cervical opening.
A total placenta previa covers and blocks the cervical opening.

What Causes Placenta Previa?

The cause of placenta previa is usually unknown, although it occurs more commonly among women who are older, smoke, have had children before, are pregnant with more than one baby (twins, triplets, or more) or have had a cesarean section or other surgery on the uterus.

Women with placenta previa,  particularly if they have a placenta previa after having delivered a previous baby by cesarean section, are at increased risk of placenta accreta, placenta increta, or placenta percreta.

In placenta accreta, the placenta is firmly attached to the uterus. In placenta increta, the placenta has grown into the uterus; and in placenta percreta, it has grown through the uterus. These conditions can sometimes be confirmed by ultrasound, CT scan, or MRI. Women with one of these conditions usually require a hysterectomy after delivery of the baby because the placenta does not separate from the uterus.

Symptoms of Placenta Previa

Some women with placenta previa don't have any symptoms. But others may have warning signs such as:

Sudden, painless vaginal bleeding - the blood is usually bright red, and the bleeding can range from light to heavy.
Symptoms of early labor - these include regular contractions and aches or pains in your lower back or belly.

Call your doctor or go to the nearest emergency room right away if you have:

Medium to heavy vaginal bleeding during the first trimester.
Any vaginal bleeding in the second or third trimester.

Treatment of Placenta Previa

Close monitoring throughout your pregnancy - In 90% of cases the placenta moves from infront of the cervical opening before you give birth

If you aren't bleeding, you may not need to be in the hospital. But you will need to be very careful.

Avoid all strenuous activity, such as running or lifting.
Call your doctor and go to the emergency room right away if you have any vaginal bleeding.

In the 10% of cases where this doesn't happen a c section is preformed due to risks involved for Mum & baby. 

If you are bleeding, you may have to stay in the hospital. If you are close to your due date, your baby will be delivered. Doctors always do a C-section when there is a placenta previa at the time of delivery. A vaginal delivery could disturb the placenta and cause severe bleeding.

If your bleeding can be slowed or stopped, your doctor may delay delivery and monitor you and your baby closely. The doctor may do:

Fetal heart monitoring to check your baby's condition.

Amniocentesis to find out if your baby's lungs are fully formed.
You may be given:

A blood transfusion if you've lost a lot of blood.

Steroid medicines if you aren't close to your due date. These medicines help get your baby ready for birth by speeding up lung development.

Tocolytic medicine to slow or stop contractions if you are in early labor.

If your newborn is premature, your baby may be treated in a neonatal intensive care unit, or NICU. Premature babies need to stay in the hospital until they can eat, breathe, and stay warm on their own.




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