Placental abruption is a condition which occurs when the placenta prematurely separates from the wall of the uterus. Another name for this is abruptio placentae. The placenta is the baby’s main life line for oxygen and nutrients, and unless it is adhering firmly to the uterine wall, there is an interruption in the flow of these vital elements.
The correct time for the placenta to separate is after the baby has been born. Ideally, this occurs as the uterus contracts down which helps the placenta to detach. It can then be passed from the vagina with the membranes which surrounded the baby.
How common is placental abruption?
It is estimated that less than 1% of women who are pregnant will develop this condition, making it a rare occurrence. Generally, it happens in relation to other risk factors, many of which are avoidable with sound, regular ante-natal care and healthy lifestyle practices.
Risks of placental abruption
The cause for placental abruption is not always clear. However, there are certain risk factors which increase the likelihood of it occurring:
- In women who have previously had a placental abruption, the risks of it recurring are increased.
- Cigarette smoking and illicit drug use, specifically cocaine and “crack” cocaine.
- A high intake of alcohol during pregnancy. More than fourteen alcoholic drinks per week during pregnancy elevates the chances of placental abruption occurring.
- Hypertension – this may be pregnancy induced hypertension (PIH) or essential hypertension.
- Poor nutrition.
- In women who have had multiple children, the risks are increased.
- Women over the age of 35 years.
- Women who have a disorder with their blood clotting and a tendency to bleed.
- Where there has been trauma to the abdomen such as a motor vehicle accident, a fall or being punched. Women who are exposed to physical blows and trauma through domestic violence are at more risk.
- In mothers who have uterine fibroids or some form of abnormality of their uterus.
- If the membranes have ruptured prematurely “PROM”. This is especially risky if there is sudden, rapid loss of amniotic fluid. This can occur during a vaginal delivery of twins after the first twin is delivered.
- For mothers carrying a multiple pregnancy such as twins, triplets or quadruplets.
- In babies who have a very short umbilical cord, the risks are increased.
Symptoms of placental abruption
There is always bleeding which occurs in placental abruption, though it is not always obvious. Bleeding can be concealed e.g. which occurs when the blood is trapped between the placenta and the uterus, effectively “containing” the blood within this space. Alternately, it can be revealed when some of the blood seeps from around the abruption, into the uterus and comes out through the vagina.
Placental abruption generally occurs from around the 20th week of pregnancy. It is a condition which is mostly restricted to the third trimester. It is almost always painful, making the mother suspect there is a problem. Other signs and symptoms include:
- Vaginal bleeding. Though 20% of women with placental abruption will not have any obvious vaginal bleeding.
- Abdominal or back pain.
- Tenderness particularly in and around the uterus.
- Uterine contractions which are not associated with labour. There can be little break between the contractions, with one coming on top of another.
Complications of placental abruption
If the abruption is partial or only small, there may be no complications at all. As long as the blood flow to the baby is not compromised there is not any danger to the mothers or the baby’s health and well-being. However, if the abruption is large and the blood loss significant, then emergency treatment is vital.
Other complications include:
- Premature delivery of the baby with the associated risks of preterm birth.
- Shock for the mother due to blood loss.
- Inadequate oxygenation of the baby which can result in cerebral palsy and death. Unfortunately, in cases where severe placental abruption occurs, around 15% of babies will die.
- Having a baby which is nutritionally compromised. Though if the placental abruption is so significant as to cause this, then caesarian section delivery is usually arranged.
- Occasionally, hysterectomy (removal of the uterus) becomes necessary for the mother if her bleeding cannot be controlled after birth.
How is placental abruption diagnosed?
- On clinical signs. The mother is examined by a midwife, obstetrician or doctor and it is suspected then diagnosed.
- On abdominal or vaginal ultrasound where the placenta can be seen sheared away from the uterine wall. Though it is important to remember that not all cases of abruption will be seen on ultrasound. * Blood tests where the mother’s blood clotting times are measured and an abnormality is suspected.
Treatment is generally based on stabilising the mother’s physical condition and increasing her blood volume. Management options also depend on the severity and location of the placental separation.
Once the placenta has started to detach, there is no specific treatment which will halt it from detaching further and there is no way to reattach it.
- Bed rest, monitoring of vital signs and general observation as long as the mother and her baby are stable.
- Intravenous fluids are commenced.
- Foetal monitoring.
- If the baby needs to be delivered early, steroid medication may be given to the mother to support her baby’s lung maturation.
- The mother may be induced to delivery her baby vaginally.
- A caesarean section delivery may be performed if the abruption is severe and the baby is sufficiently mature.
- Excessive blood loss leading to maternal shock.
- Foetal distress due to inadequate circulating oxygen and nutrients being filtered through to the baby.