Preeclampsia is a condition in which high blood pressure (pregnancy-induced hypertension), proteinuria (protein in the urine), edema (swelling) and excessive weight gain occur during pregnancy. The condition usually occurs after the 20th week of pregnancy.
What is going on in the body?
The placenta is the spongy material in the mother's uterus that nourishes the unborn child. Some experts believe that a problem with the placenta causes preeclampsia.
The mother has spasms of the blood vessels, which increase her blood pressure. The blood flow to the placenta is impaired. If the blood pressure is not controlled, it can damage the placenta and cause the death of the unborn child.
Preeclampsia develops in 2-4% of pregnant women. It usually occurs after the 20th week of pregnancy. It may be mild or severe.
The high blood pressure can affect the brain, kidneys, liver, and lungs. If the high blood pressure in the brain causes swelling of or bleeding into the brain, the woman may have seizures. This complication is called eclampsia.
One in 2000 pregnant women who have preeclampsia will go on to have eclampsia in developed countries, while this is true in 1 in 100 to 1 in 1700 women in developing countries. The seizures of eclampsia are marked by general abnormal electrical activity in the brain.
Usually the seizures start before the baby is born. Nearly all seizures begin within the first 24 hours after the baby is born. However, a few women develop seizures later, up to 3 weeks after the birth.
What are the causes and risks of the condition?
Factors that increase a woman's risk of preeclampsia are:
a first pregnancy
African American ethnicity
high blood pressure or chronic renal disease before pregnancy
family history of pregnancy-induced hypertension
low socioeconomic status
maternal age below 20 or over 35
molar pregnancy, an abnormal condition that mimics a normal pregnancy but is actually a tumor
multiple gestation such as twins or triplets
preeclampsia or eclampsia in previous pregnancies
she or the baby's father was born of a pregnancy with preeclampsia or eclampsia
one of the thrombophilias
No one knows why some women with preeclampsia
develop the seizures
associated with eclampsia. Theories about why seizures might occur in pregnancy involve:
- small clots that block blood vessels in the brain and restrict oxygen
- narrowing of tiny arteries in the brain
- areas of bleeding in the brain
- high blood pressure
- dietary risks
- genetic risks
- a problem with the brain or nervous system
What can be done to prevent the condition?
There are no known ways to prevent preeclampsia
or eclampsia. All pregnant women should have early prenatal care. Blood pressure
changes should be watched closely.
How is the condition diagnosed?
Diagnosis of preeclampsia
begins with a medical history and physical exam. The woman's blood pressure
will be measured. The healthcare provider may order the following tests:
- complete blood count, or CBC, to look for abnormal blood cell counts
- blood tests to check clotting and liver function
to look for protein in the urine
- cranial CT scan
to check for bleeding or stroke
- pregnancy ultrasound
to check the age and condition of the fetus
If a woman develops seizures
along with preeclampsia, she is then diagnosed as having eclampsia.
Long Term Effects
What are the long-term effects of the condition?
Eclampsia may cause pregnancy complications, including:
- increased risk for cesarean section
- intrauterine growth retardation, a lack of normal growth of the baby within the womb
- placenta abruptio, or separation of the placenta from the uterine wall
- premature labor
- suffocation at birth, or asphyxia
Eclampsia can also cause health problems that affect mother and baby, including:
- acute renal failure, or kidney failure
- disseminated intravascular coagulation, or DIC, a clotting problem that causes widespread bleeding
- HELLP syndrome,
which includes liver and blood disorders
- intracerebral hemorrhage
Rarely, a mother with eclampsia dies due to blood clots, liver or kidney failure, infection, or other complications. Women who have had eclampsia also have a higher lifetime risk of developing high blood pressure and dying due to heart attacks
What are the risks to others?
Eclampsia is not contagious. Both mother and baby are at risk for complications of preeclampsia and eclampsia.
What are the treatments for the condition?
Eclampsia is treated by delivering the baby. If the baby is 24 weeks or older and the cervix is unfavorable for labor, a cesarean birth is usually done. During a cesarean, the baby is delivered through an incision made in the abdomen.
Prolonging the pregnancy can harm the mother or cause the baby to die. Before a cesarean is done, the mother's seizures and blood pressure may need to be controlled with medicines. Magnesium sulfate is the medicine of choice to prevent and control seizures.
Diazepam (i.e., Valium) may be used if the magnesium sulfate doesn't stop seizures. Medicines such as hydralazine (i.e., Apresoline), diazoxide (i.e., Hyperstat, Proglycem), and labetalol (i.e., Trandate) can be used to lower the blood pressure.
What are the side effects of the treatments?
A cesarean birth may cause bleeding, infection, or even death. Medicines used to treat eclampsia may cause low blood pressure, breathing difficulties, nausea, or allergic reactions.
What happens after treatment for the condition?
After the baby is born, a woman may still have seizures for up to 6 weeks. Her provider will closely monitor blood pressure, urine and blood tests, and any other symptoms. If a baby is born prematurely and has health problems, hospitalization and care will be needed.
Twenty-five percent of women with eclampsia will have hypertension in subsequent pregnancies, but only 5% of these will be sever and only 2% will be eclamptic again.
Also, multiparous women with eclampsia (eclampsia in a pregnancy that is not the first pregnancy) are at higher risk for essential hypertension later in life and are at a higher risk for higher mortality in subsequent pregnancies.
How is the condition monitored?
Preeclampsia may recur in later pregnancies. Early prenatal care is key to recognizing warning signs and managing the condition. Any new or worsening symptoms should be reported to the healthcare provider.