Women may have vaginal bleeding and/or severe abdominal pain and go into shock.
When the placenta detaches too soon, the fetus may not grow as much as expected or may even die.
Doctors diagnose placental abruption based on symptoms and sometimes do ultrasonography to confirm the diagnosis.
Limiting activity may be all that is needed, but if bleeding continues, if the fetus is in danger, or if the pregnancy is at term, the baby is delivered as soon as possible.
Pregnancy complications, such as placental abruption, are problems that occur only during pregnancy. They may affect the woman, the fetus, or both and may occur at different times during the pregnancy. However, most pregnancy complications can be effectively treated.
The placenta may detach incompletely (sometimes just 10 to 20%) or completely. The cause is unknown.
Detachment of the placenta occurs in 0.4 to 1.5% of all pregnancies.
Problems With the Placenta
Normally, the placenta is located in the upper part of the uterus, firmly attached to the uterine wall until after delivery of the baby. The placenta carries oxygen and nutrients from the mother to the fetus.
In placental abruption (abruptio placentae), the placenta detaches from the uterine wall prematurely, causing the uterus to bleed and reducing the fetus’s supply of oxygen and nutrients. Women who have this complication are hospitalized, and the baby may be delivered early.
In placenta previa, the placenta is located over the cervix, in the lower part of the uterus. Placenta previa may cause painless bleeding that suddenly begins late in pregnancy. The bleeding may become profuse. The baby is usually delivered by cesarean.
Risk factors (conditions that increase the risk of a disorder) for placental abruption include the following:
High blood pressure High Blood Pressure During Pregnancy High blood pressure (hypertension) during pregnancy is classified as one of the following: Chronic hypertension: Blood pressure was high before the pregnancy. Gestational hypertension: Blood... read more (including preeclampsia Preeclampsia and Eclampsia Preeclampsia is new high blood pressure or worsening of existing high blood pressure that is accompanied by excess protein in the urine and that develops after the 20th week of pregnancy. Eclampsia... read more , a type of high blood pressure that develops during pregnancy)
Previous placental abruption
Infection in the tissues around the fetus ( intra-amniotic infection Intra-Amniotic Infection Intra-amniotic infection is infection of the tissues around the fetus, such as the fluid that surrounds the fetus (amniotic fluid), the placenta, the membranes around the fetus, or a combination... read more )
Premature rupture of the membranes Prelabor Rupture of the Membranes (PROM) Prelabor rupture of the membranes is the leaking of amniotic fluid from around the fetus at any time before labor starts. After the membranes rupture, labor often soon follows. If labor does... read more , especially when there is too much amniotic fluid Too much amniotic fluid Amniotic fluid is the fluid that surrounds the fetus in the uterus. The fluid and fetus are contained in membranes called the amniotic sac. Problems with amniotic fluid include Too much amniotic... read more around the fetus (polyhydramnios)
Lack of oxygen to the placenta
Symptoms of Placental Abruption
Symptoms of placental abruption depend on the degree of detachment and the amount of blood lost (which may be massive).
Symptoms may include sudden continuous or crampy abdominal pain, tenderness when the abdomen is gently pressed, and dangerously low blood pressure ( shock Shock Shock is a life-threatening condition in which blood flow to the organs is low, decreasing delivery of oxygen and thus causing organ damage and sometimes death. Blood pressure is usually low... read more ). Some women have no symptoms.
The uterus bleeds from the site where the placenta has detached. The blood may pass through the cervix and out the vagina as an external hemorrhage, or the blood may be trapped behind the placenta as a concealed hemorrhage. Thus, women may or may not have vaginal bleeding. If bleeding occurs, the blood may be bright or dark red, and bleeding may be continuous or spotty.
Premature detachment of the placenta sometimes leads to severe blood loss with widespread clotting inside the blood vessels ( disseminated intravascular coagulation Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation is a condition in which small blood clots develop throughout the bloodstream, blocking small blood vessels. The increased clotting depletes the platelets... read more ), kidney failure Acute Kidney Injury Acute kidney injury is a rapid (days to weeks) decline in the kidneys’ ability to filter metabolic waste products from the blood. Causes include conditions that decrease blood flow to the kidneys... read more , and bleeding into the walls of the uterus, especially in pregnant women who also have preeclampsia.
When the placenta detaches, the supply of oxygen and nutrients to the fetus may be reduced. If detachment occurs suddenly and greatly reduces the oxygen supply, the fetus may die. If it occurs gradually and less extensively, the fetus may not grow as much as expected ( intrauterine growth restriction Small-for-Gestational-Age (SGA) Newborn A newborn who weighs less than 90% of newborns of the same gestational age at birth (below the 10th percentile) is considered small for gestational age. Newborns may be small because their parents... read more ) or there may be too little amniotic fluid Too little amniotic fluid Amniotic fluid is the fluid that surrounds the fetus in the uterus. The fluid and fetus are contained in membranes called the amniotic sac. Problems with amniotic fluid include Too much amniotic... read more (oligohydramnios). Gradual detachment may cause less abdominal pain and have a lower risk of shock in the mother than sudden detachment, but the risk of subsequent premature rupture of the membranes is increased.
Diagnosis of Placental Abruption
A doctor's evaluation
Doctors suspect and usually diagnose premature detachment of the placenta based on symptoms. Ultrasonography may help doctors confirm the diagnosis of premature detachment and distinguish it from placenta previa Placenta Previa Placenta previa is attachment (implantation) of the placenta over the opening of the cervix, in the lower rather than the upper part of the uterus. Women may have painless, sometimes profuse... read more , which can cause similar symptoms. Ultrasonography may be done by placing a handheld device on the abdomen (called abdominal ultrasonography) or inside the vagina (called transvaginal ultrasonography).
Doctors may check for preeclampsia because it can increase the risk of problems.
To check for problems that premature detachment can cause, doctors may do blood tests and may monitor the fetus's heart rate Fetal monitoring Labor is a series of rhythmic, progressive contractions of the uterus that gradually move the fetus through the lower part of the uterus (cervix) and birth canal (vagina) to the outside world... read more .
Treatment of Placental Abruption
Sometimes hospitalization and modified activity
Sometimes prompt delivery
A woman with premature detachment of the placenta may be hospitalized depending on how severe the symptoms are and how long the pregnancy has lasted. Sometimes the only treatment needed is modified activity (modified bed rest). Modified activity means that the woman should stay off her feet most of the day. Doctors also advise against sexual intercourse.
Modified activity with hospitalization is appropriate if all of the following are present:
The bleeding does not threaten the life of the mother or fetus but continues.
The fetus's heart rate is normal.
The pregnancy is preterm (less than 37 weeks).
This approach enables doctors to closely monitor the woman and fetus and, if needed, rapidly treat them. Usually, when the risk of early delivery is high, corticosteroids are also recommended (to help the fetus's lungs mature). If symptoms lessen and the fetus is not in danger, the woman may be discharged from the hospital.
Delivery is usually done as soon as possible if any of the following is present:
Bleeding continues or worsens.
The fetus's heart rate is abnormal (suggesting that the fetus is not getting enough oxygen).
The pregnancy is at term (37 weeks or more).
If vaginal delivery is not possible, a cesarean delivery Cesarean Delivery Cesarean delivery is surgical delivery of a baby by incision through a woman’s abdomen and uterus. In the United States, up to 30% of deliveries are cesarean. Doctors use a cesarean delivery... read more is done.
If the woman goes into shock or disseminated intravascular coagulation develops, the woman is given blood transfusions and monitored in an intensive care unit.