Placental abruption occurs in about 1% of all births. There is a higher risk of this happening after 20 weeks of pregnancy, but it can happen anytime up to delivery. Placental abruption is a primary cause of maternal morbidity and perinatal mortality.

The precise cause of placental abruption is unknown. Its incidence is, however, linked to several risk factors. There are three categories of risk factors: health history (including habits and previous obstetrical events); present pregnancy; and unanticipated trauma. 

Placental abruption can show up in different ways for each person. But during the third trimester of pregnancy, bleeding and cramping in the uterus are the most common signs. Some other signs and symptoms are:

• Abdominal pain;
• Contractions in the uterus that are longer and stronger than normal contractions during labor;
• Uterine tenderness;
• Back pain;
• Decreased fetal movement.

Back and abdominal pain often starts quickly. Vaginal bleeding is not a reliable indicator of placenta separation because the blood may remain in the uterus even with a severe placental abruption. Chronic placental abruption may cause modest, intermittent vaginal bleeding.

There are no definitive laboratory tests or diagnostic techniques for determining placental abruption. But some studies might be done to rule out other causes.

An ultrasound can help find out where the placenta is and rule out the possibility of a condition called placenta previa.

A biophysical profile may be used when treating patients with marginal placental abruption in a conservative way. A score of 6 or less shows that the health of the fetus is not good.

Blood tests, such as a complete blood count (CBC), clotting studies (fibrinogen and PT/a-PTT), and BUN, can be used to measure changes in the patient’s condition.

The Kleihauer-Betke test, which looks for fetal blood cells in the mother’s blood, could be offered. A Kleihauer-Betke test does not tell if there has been a placental abruption, but it does measure how much fetal blood is in the mother’s bloodstream.

Treatment

Once the placenta has detached from the uterus, it cannot be reattached or restored. A doctor will suggest treatment based on the following:

• Abruption severity;
• Pregnancy length/fetal age;
• Fetal distress;
• Blood loss.

The fetus’ gestational age and abruption severity are the most relevant factors.

If the fetus is not near term

If the abruption is minor, the patient will be continuously followed until 34 weeks of pregnancy. If the fetal heart rate is normal and the patient is not bleeding, the doctor may let the patient rest at home. They may provide fetal lung development medicines;

If the fetus is almost full-term

A closely monitored vaginal birth is possible if the abruption is minor and the fetal heart rate is stable. Most of the time, this is decided around 34 weeks. If the abruption worsens, the baby will be delivered by emergency cesarean section.

Placental abruptions are unavoidable. You can lower the risk by:

• Not smoking or using drugs;
• Controlling blood pressure;
• Managing diabetes;
• Safety measures like wearing a seat belt;
• Informing your doctor about abdominal trauma;
• Discussing vaginal bleeding with your physician.

References

Schmidt P, Skelly CL, Raines DA. Placental Abruption. [Updated 2022 Apr 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482335/

Cleveland Clinic (2022). Placental Abruption. Retrieved November 9, 2022, https://my.clevelandclinic.org/health/diseases/9435-placental-abruption

Mayo Clinic (2022). Placental Abruption. Retrieved November 9, 2022, https://www.mayoclinic.org/diseases-conditions/placental-abruption/diagnosis-treatment/drc-20376462