Preeclampsia-an incurable condition occurring in nearly 10 percent of pregnancies-is among the most poorly understood medical disorders. But new research on dietary calcium offers hope for the prevention of this potentially life-threatening condition.
The condition is marked by high blood pressure (hypertension), swelling (often in the feet, legs and hands), seizures and high amounts of protein in a woman's urine. Women with chronic hypertension, diabetes, kidney disease or a history of preeclampsia are at greater risk.
A new medical review claims that by increasing calcium intake, pregnant women may reduce their likelihood for developing preeclampsia. The review was published by the Cochrane Collaboration, an international group that evaluates medical research.
The reviewers analyzed 12 studies, including one with more than 4,000 pregnant women in North America and another involving more than 12,000 women internationally. They found that women with low dietary calcium who were given calcium supplements-as opposed to women who received a placebo-had a lower risk of hypertension, preeclampsia and severe complications, including death.
However, the study's reviewers didn't note a dramatically reduced risk in communities where women received better prenatal care and had adequate dietary calcium, leaving room for some skepticism.
Preventing preeclampsia or reducing its severity would decrease maternal and fetal morbidity rates throughout the world and lessen other consequences of this disorder, which is diagnosed by the appearance of new onset hypertension and increased urinary protein after 20 weeks of pregnancy. Other complaints that might lead a physician to a diagnosis of preeclampsia include headaches, visual disturbances, nausea and abdominal pain.
Cause still unclear
"This is a disease that's peculiar to pregnancy," says Dr. Marshall Lindheimer, a nephrologist and professor of medicine and obstetrics and gynecology at the University of Chicago. Lindheimer is also on the medical advisory board for the nonprofit Preeclampsia Foundation, www.preeclampsia.org.
"We're still not 100 percent certain of its cause," says Lindheimer, who also co-founded the International Society for the Study of Hypertension in Pregnancy. "Predicting and preventing it would really be huge."
Besides not knowing much about what causes the condition, experts say it can have wide-ranging effects on those suffering from it.
"The problem with preeclampsia is that it's basically a blood vessel issue and can pretty much affect any organ," says Dr. Virgil C. Reid III, head of the women's health department at Erie Family Health Center in Chicago and a clinical assistant professor of obstetrics and gynecology at Northwestern University's Feinberg School of Medicine.
Because it's a multi-system disorder, it can also have additional manifestations, including low platelet count and abnormal liver enzymes. Doctors can run tests for some of these conditions to expedite diagnosis.
"There is no cure for preeclampsia except for delivery," adds Reid. If it occurs later in pregnancy, this isn't a problem, but when preeclampsia is early, especially before 32 weeks, doctors will try to gain time for the fetus to grow. In many cases, prescribing a blood-pressure medication is the best way to do this.
Though rare, untreated preeclampsia can progress to eclampsia, which in extremely unusual cases can cause coma and even death of the mother and baby before, during or after childbirth. Other dangers include premature birth, growth restriction or placental abruption (where the placenta separates from the wall of the uterus). Kidney and liver damage are among potential consequences for the mother.
Results aren't definitive
Although the medical review sheds new light on a possible prevention method for preeclampsia, its practical implications are unclear.
"I'm not sure if the results can definitively be applied to the United States," says Reid. The U.S. recommended daily calcium allowance is 1,200 milligrams. Doctors say there is no harm in taking extra calcium during pregnancy.
"While I can't guarantee it'll help, I know it won't hurt," Reid says.
Nevertheless, the study's conclusions are a sign of progress. Despite a dramatic reduction in recent years, preeclampsia and eclampsia still are a leading cause of maternal, fetal and infant mortality.
Past research focused on prevention through supplements such as vitamins C and E, antioxidants and aspirin. With aspirin, "in fact, there were some increased complications," says Reid.
"We now have a better understanding of how the signs and symptoms of the disease come about and we have enough information to start experiments that may one day prevent and cure preeclampsia," says Lindheimer. "It makes common sense that something that every pregnant woman should be taking enough of, and has some indication of reducing the severity of preeclampsia, should be taken."
Maayan S. Heller is a writer from Massachusetts now living in Chicago covering women's health issues.