Medically Reviewed by Dr. K on 4 March 2021
Table of contents
What Is Placental Abruption?
The placenta develops within the uterus throughout pregnancy. It supplies nutrients and oxygen from mum to baby during pregnancy, and it is responsible for removing waste from baby’s blood during pregnancy. The placenta is directly attached to the wall of the uterus, whilst the baby is connected to the umbilical cord within the uterus. Placental abruption occurs when the placenta suddenly detaches from the wall of the uterus during pregnancy, before it is supposed to do so. This is a sudden occurrence that can be very dangerous to both mother and baby.
Signs and Symptoms
Placental abruption occurs in roughly 1% of all pregnancies. It may potentially happen after 20 weeks of pregnancy, but it’s most likely to occur during the third trimester.
Signs and symptoms include:
- Vaginal bleeding – occasionally there may not be vaginal bleeding
- Abdominal pain
- Back pain
- Uterine tenderness
- Uterine contractions – often consecutively
- Unstable fetal heart rate
The volume of vaginal bleeding does not correlate to how much of the mother’s placenta has detached from the wall of the uterus. Due to the placement of the placenta, on occasion, the bleeding can be trapped behind the placenta within the uterus. Because of this, a severe placental abruption may not have any visible bleeding.
Abdominal and back pain associated with placental abruption will be a sudden occurrence and can be quite intense.
There are documented cases of slowly detaching placentas, this is called chronic abruption. For this particular type of placental abruption, the vaginal bleeding can be milder and intermittent. This can result in your baby not growing as expected throughout pregnancy and there may be a low volume of amniotic fluid, alongside other complications.
The underlying cause of placental abruption is not known, however there are clear factors that increase the risk of it. Alcohol consumption and cocaine abuse during pregnancy
- Alcohol consumption during pregnancy
- Smoking during pregnancy: studies have shown that women who smoked prior to getting pregnancy increased their risk of suffering a placental abruption by 40% for each year that these women smoked
- Cocaine abuse or other recreational drug abuse: women who abuse recreational drugs during pregnancy had a 10% risk of developing placental abruption in the last trimester of pregnancy
- Placental abruptions in previous pregnancies increased the likelihood of recurrence in subsequent pregnancies by 10%
- High blood pressure in women who were pregnant
- Amniotic sac issues: The amniotic sac is responsible for protecting and cushioning your baby within the uterus. If the amniotic sac leaks, the risk of placental abruption increases.
- Getting pregnant at an older age, above 35 years old
- Multiple pregnancies: being pregnant with more than one fetus
- Abdominal trauma
If you have had placental abruption in previous pregnancies, or are worried about your risks, you should tell your doctor. Your doctor will be able to closely monitor your pregnancy and advice on different methods in which you can prevent it.
If you are experiencing any symptoms listed above, seek medical attention immediately. Your doctor will complete a full physical examination and blood test, alongside an ultrasound to check on the baby within the uterus.
Once the placenta has detached, it is not possible to reattach it. Depending on the severity of the abruption and medical stability of mother and baby, a treatment plan will be devised by the medical team.
- Pregnancy under 34 weeks: Hospital admission with monitoring of mother and baby if the baby’s heart rate is stable and the placental abruption is not so severe. If the baby appears stable, then a plan for discharge home may be in place.
- Pregnancy over 34 weeks:
- For mild placental abruptions, vaginal delivery can still be continued
- For severe placental abruptions, C-section will need to be considered especially if the baby is in distress. A blood transfusion may also be needed if the mother has bled a lot
Smaller placental abruptions may not cause serious consequences, however if a large portion of the placental separates, it can be dangerous to both mother and baby.
Dangerous effects to mother can include:
- Major blood loss can lead to systemic shock in your body, and you will require a blood transfusion for stabilisation.
- defective blood clotting cascade
- kidney injury and potential kidney failure
- major organ failure
- death of fetus
- death of mother
Dangerous effects to baby includes:
- premature birth, born before 37 weeks
- developmental delay if baby is born very premature that affects normal milestones
- stillbirth of fetus
Referenced on 4.3.2021:
- Mayo Clinic: “Placental abruption,” “Placenta: How it Works, What’s Normal?”
- March of Dimes: “Placental Abruption.”
- Medscape: “Abruptio Placentae.”
- Cedars Sinai: “Placental Abruption.”