Illustration depicting internal and external bleeding from placental abruption
Placental abruption (also known as abruptio placentae) is a complication of pregnancy, wherein the placental lining has separated from the uterus of the mother. It is the most common pathological cause of late pregnancy bleeding. In humans, it refers to the abnormal separation after 20 weeks of gestation and prior to birth. It occurs in 1% of pregnancies worldwide. Placental abruption is a significant contributor to maternal mortality worldwide; early and skilled medical intervention is needed to ensure a good outcome, and this is not available in many parts of the world. Treatment depends on how serious the abruption is and how far along the woman is in her pregnancy.
Placental abruption has effects on both mother and fetus. The effects on the mother depend primarily on the severity of the abruption, while the effects on the fetus depend on both its severity and the gestational age at which it occurs. The heart rate of the fetus can be associated with the severity.
Trauma, hypertension, or coagulopathy contributes to the avulsion of the anchoring placental villi from the expanding lower uterine segment, which in turn, leads to bleeding into the decidua basalis. This can push the placenta away from the uterus and cause further bleeding. Bleeding through the vagina, called overt or external bleeding, occurs 80% of the time, though sometimes the blood will pool behind the placenta, known as concealed or internal placental abruption.
Women may present with vaginal bleeding, abdominal or back pain, abnormal or premature contractions, fetal distress or death.
Abruptions are classified according to severity in the following manner:
Grade 0: Asymptomatic and only diagnosed through post partum examination of the placenta.
Grade 1: The mother may have vaginal bleeding with mild uterine tenderness or tetany, but there is no distress of mother or fetus.
Grade 2: The mother is symptomatic but not in shock. There is some evidence of fetal distress can be found with fetal heart rate monitoring.
Although the risk of placental abruption cannot be eliminated, it can be reduced. Avoiding tobacco, alcohol and cocaine during pregnancy decreases the risk. Staying away from activities which have a high risk of physical trauma is also important. Women who have high blood pressure or who have had a previous placental abruption and want to conceive must be closely supervised by a doctor.
It is crucial for women to be made aware of the signs of placental abruption, such as vaginal bleeding, and that if they experience such symptoms they must get into contact with their health care provider/the hospital without any delay.
Placental abruption is suspected when a pregnant mother has sudden localized abdominal pain with or without bleeding. The fundus may be monitored because a rising fundus can indicate bleeding. An ultrasound may be used to rule out placenta praevia but is not diagnostic for abruption. The mother may be given Rhogam if she is Rh negative.
Treatment depends on the amount of blood loss and the status of the fetus. If the fetus is less than 36 weeks and neither mother or fetus is in any distress, then they may simply be monitored in hospital until a change in condition or fetal maturity whichever comes first.
Immediate delivery of the fetus may be indicated if the fetus is mature or if the fetus or mother is in distress. Blood volume replacement to maintain blood pressure and blood plasma replacement to maintain fibrinogen levels may be needed. Vaginal birth is usually preferred over caesarean section unless there is fetal distress. Caesarean section is contraindicated in cases of disseminated intravascular coagulation. Patient should be monitored for 7 days for PPH. Excessive bleeding from uterus may necessitate hysterectomy.
The prognosis of this complication depends on whether treatment is received by the patient, on the quality of treatment, and on the severity of the abruption.
In the Western world, maternal deaths due to placental abruption are rare; for instance a study done in Finland found that, between 1972 and 2005 placental abruption had a maternal mortality rate of 0.4 per 1,000 cases (which means that 1 in 2,500 women who had placental abruption died); this was similar to other Western countries during that period. The prognosis on the fetus is worse, currently, in the UK, about 15% of fetuses die following this event.
Without any form of medical intervention, as often happens in many parts of the world, placental abruption has a high maternal mortality rate.
^Usui, Rie; Matsubara, Shigeki; Ohkuchi, Akihide; Kuwata, Tomoyuki; Watanabe, Takashi; Izumi, Akio; Suzuki, Mitsuaki (2007). "Fetal heart rate pattern reflecting the severity of placental abruption". Archives of Gynecology and Obstetrics277 (3): 249–53. doi:10.1007/s00404-007-0471-9. PMID17896112.
^Ananth, C (1999). "Incidence of placental abruption in relation to cigarette smoking and hypertensive disorders during pregnancy: A meta-analysis of observational studies". Obstetrics & Gynecology93 (4): 622. doi:10.1016/S0029-7844(98)00408-6.