What is a placental abruption?
A placental abruption is a serious condition in which the placenta separates from your uterus before your baby is born. It can separate partially (partial placental abruption) or completely (complete placental abruption). This can happen before or during labor.
The condition can deprive your baby of oxygen and nutrients and cause severe bleeding that can be dangerous to you both. A placental abruption also increases the risk that your baby will have growth problems (if the abruption is small and goes unnoticed), be born prematurely, or be stillborn.
Placental abruption happens in about one in 150 pregnancies. It's most common in the third trimester but can happen any time after 20 weeks.
What are the signs of a placental abruption?
Call your practitioner immediately if you have any of these signs that can indicate placental abruption:
- Vaginal bleeding or spotting, or if your water breaks and the fluid is bloody. In most cases of placental abruption, you'll have some vaginal bleeding, ranging from a small amount to an obvious and sudden gush. Sometimes, though, the blood stays in the uterus behind the placenta, so you might not see any bleeding at all.
- Cramping, uterine tenderness, abdominal pain, or back pain.
- Frequent contractions or a contraction that doesn't end. In close to a quarter of cases, an abruption will cause the woman to go into labor prematurely.
- Your baby isn't moving as much as before.
Call 911 if you're bleeding heavily or have any signs of shock – if you feel weak, faint, pale, sweaty, or disoriented, or your heart is pounding.
What will happen at the hospital?
If you have any signs of a placental abruption, you'll get a complete evaluation at the hospital, including a physical exam, fetal heart rate monitoring, and an ultrasound.
Since not all vaginal bleeding may be coming from the uterus, your practitioner will examine your vagina and cervix to see if the bleeding is from another cause, such as an infection, a laceration, or a cervical polyp.
If you're Rh negative and you have any vaginal bleeding, you'll need a shot of Rh immune globulin, unless the biological father is also Rh negative.
Will I have to deliver my baby right away if I have a placental abruption?
If you're near your due date, you'll need to deliver your baby right away, even if the abruption is minor, because the placenta could separate further at any time. If you're bleeding heavily or there are signs the baby is not getting enough oxygen, you'll have a c-section.
However, if you have a small amount of bleeding that your provider suspects is from a minor abruption, and you and your baby are doing fine, you may be allowed to labor, as long as you're at a hospital where an emergency c-section can be done at the first sign of trouble.
If your provider suspects that you have a minor abruption and your baby is very premature, you may be able to delay delivery a bit, as long as you and your baby are doing fine. At this point you have to weigh the risk of a worsening abruption against the risk of a premature birth.
You may be given corticosteroids to speed the development of your baby's lungs and to prevent certain other problems related to prematurity. You'll stay in the hospital and be monitored closely so your medical team can get your baby out at the first sign that the abruption is getting worse or that you or your baby is no longer doing fine.
Who's most at risk for placental abruption?
No one knows for sure what causes most cases of placental abruption, but the condition is more common in women who:
- Had an abruption in a previous pregnancy (and if you've had an abruption in two or more pregnancies, the risk is even higher)
- Have chronic hypertension, gestational hypertension, or preeclampsia
- Have a blood clotting disorder
- Have their water break prematurely (before 37 weeks)
- Have too much amniotic fluid (polyhydramnios)
- Had bleeding earlier in their pregnancy
- Are carrying multiples (abruption is especially common just after the first baby is delivered)
- Are involved in an accident (particularly a car accident), are assaulted (with blows to the abdomen), or have other trauma to the abdomen during pregnancy
- Smoke tobacco or use methamphetamines or cocaine, or drink alcohol excessively
- Have had many babies or are older (the risk gradually goes up with age)
- Have a uterine abnormality or fibroids (particularly if there's a fibroid behind the place where the placenta is attached)