The placenta is an extraordinary organ that develops inside your uterus (womb) when you are pregnant. It provides your baby with nutrients and oxygen from your blood. When something goes wrong with the placenta, it can be serious and even life-threatening both to the mother and the baby.
The placenta is normally attached to the top or side of the uterus and connects to the baby through the umbilical cord. By the time the baby is born, a normal placenta will weigh between 700 and 800 grams.
In a normal birth, the placenta is delivered through the vagina, usually 5 to 30 minutes after the baby is born. This is known as the third stage of labour. If you have a caesarean, the doctor will remove the placenta at the same time as the baby.
What's not normal?
Sometimes the placenta does not grow as it should. This can affect the growth and health of the baby, and cause complications during birth.
- Placenta accreta: When the placenta grows too deeply into the wall of the uterus. This can lead to massive blood loss during or after delivery and can be life-threatening.
- Placental abruption: When the placenta peels away from the wall of the womb before delivery. This can cause bleeding and will mean your baby may not be getting all the nutrients they need. In some cases, an early delivery may be needed.
- Placenta praevia: When the placenta partially or totally covers the cervix, the opening through which the baby will come out. This condition is more common early in pregnancy and often resolves as the placenta moves higher in the uterus as the uterus grows. If the placenta is still covering the cervix close to the time of delivery, a caesarean section will be necessary.
- Placental insufficiency: When the placenta doesn’t work properly during pregnancy, depriving the baby of oxygen and nutrients. This can affect the growth of the baby.
- Retained placenta: The placenta may not come out after the birth because it is blocked by the cervix or it is still attached to the uterus. This can cause severe infection or blood loss, and can be life-threatening.
How will I know there is something wrong with my placenta?
There are signs you should look out for during your pregnancy that might indicate there is a problem with your placenta. In some cases, you might not know anything is wrong and it is something your doctor finds during routine antenatal tests and ultrasounds.
The main signs that something may be wrong with the placenta are:
- bleeding from your vagina, which may range from quite light to very heavy, depending on the problem
- pain, either in your tummy or back
Some women have bleeding but no pain; others may experience sudden and very severe abdominal pain but no bleeding. If you have any of these symptoms, seek medical attention immediately.
What to do if you think there may be a problem
If you have any vaginal bleeding during the second or third trimester, it’s important to see your doctor as soon as possible. If the bleeding is severe and you have significant pain, call triple zero (000) for an ambulance or go to your nearest hospital emergency department.
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Last reviewed: February 2020