What is it?
Placental abruption is a serious pregnancy condition in which the placenta separates or partially separates from the uterine wall before the baby’s birth. This breaks the blood supply between the mother and baby, which can be dangerous because the placenta is involved in the transfer of nutrients, oxygen and release waste between mother and baby during pregnancy.
The repercussions for both mother and baby can be fatal when the abruption leads to the mother’s blood loss, haemorrhaging or organ failure, or when there is distress to the baby caused by a lack of oxygen and nutrients.
The chance of a placental abruption occurring increases with each of the following factors:
• harm to the uterus during pregnancy, such as an injury sustained when being assaulted, in a car accident or through a fall
• a short umbilical cord
• the delay of the rupturing of the membranes during labour
• smoking during pregnancy
• being pregnant with more than one baby
• being very young or over 35
• having had a placental abruption in a previous pregnancy
• having had a caesarean in a previous pregnancy
• an infection in the uterus
• high blood pressure
• uterine fibroids
• an excess of amniotic fluid and/or the amnioreduction procedure
• having been pregnant many times
• certain blood disorders.
Placental abruption happens most often during the final trimester, although it can take place any time from four months onwards. It occurs in about 1 out of 150 deliveries, but the most severe form is estimated to occur in only about 1 out of 800 to 1600 births.
What are the symptoms?
Signs that the placenta may have detached include:
• regular contractions or premature labour
• pain and tenderness in the uterus
• abdominal and back pain
• bleeding (this can happen when the blood leakage spills into the vagina)
• visible swelling or hardening of the uterus.
How is it diagnosed?
Ultrasounds, blood cell counts and foetal heart rate monitoring can all be used to detect placental abruption.
What's the treatment?
Where the abruption is only partial and blood flow loss is minimal, doctors may recommend bed rest, preferring to monitor the baby while waiting for it to be delivered as close to the due date as possible.
A complete abruption may require an emergency caesarean, depending on how the baby’s health is being affected.
If a placental abruption causes the mother to lose large amounts of blood, a transfusion may be required. In the most serious circumstances, a hysterectomy may be needed to stop the bleeding.
Does it affect the baby?
Placental abruption can cause low blood count in the baby, because the placenta can’t be reattached once it begins to separate. In some cases it can lead to an emergency caesarean, delivering the baby earlier than expected.
Occasionally, blood can collect between the placenta and the uterine wall. This is referred to as a concealed placental abruption and can result in the abruption going unnoticed, leading to intrauterine growth restriction, possible brain damage and stillbirth.
If left untreated, placental abruption can be fatal.
The incidence of complete placental abruption is very low, but women who have experienced it have a much higher chance of it happening again. In this case, they will be monitored very closely in subsequent pregnancies.
Facts verified by Dr Raewyn Teirney. Dr Raewyn Teirney is gynaecologist, obstetrician and fertility specialist and a visiting medical officer at the Royal Hospital for Women in Sydney, and also consults from her private rooms at Maroubra and Kogarah.