High-risk pregnancies are on the rise in the United States and may be more common now than at any other time since modern obstetric care became available.
Why? More fortysomething moms are having babies, and epidemics of diabetes, obesity and high blood pressure are causing pregnancy and birth complications.
In this otherwise troubling trend is also some good news: A small but growing number of women are successfully having children despite life-threatening conditions that once made a safe pregnancy almost inconceivable.
Exact numbers are not available, but doctors say that tens of thousands of organ transplant recipients, breast cancer survivors, women with heart defects, and even women with the AIDS virus have decided to risk childbearing in the last several years.
Not all of these stories have happy endings, and many people worry that some of these women will not live long enough to raise their children, or that they will pass on their medical problems.
Most results have been so surprisingly good that they are overturning decades of gloomy dogma about who is medically fit to have a child.
"These people define a whole new era of pregnancy for us," said Temple University's Dr. Vincent Armenti, who runs a registry that tracks births to transplant patients.
"We have to change our mindset about the perfect pregnancy," he said. Women should be given advice based on solid research "instead of an emotional feeling that some people just shouldn't have a baby."
No one knows precisely how many high-risk pregnancies there are. It is a catchall term that in the past has meant the mom is over 35 or has a condition like high blood pressure that is dangerous for her or her fetus. But as these situations have become more common, even this loose definition is changing.
Births to women 35 and older are soaring. And many complications are becoming so routine that nurse midwives can manage them instead of sending women to high-risk care specialists. Doctors around the country say they are treating far more of these risky cases than they did a decade ago.
"Patients are getting older, so by definition, they're higher-risk. The diabetes rate is going through the roof, so that's high-risk. More people with high blood pressure are getting pregnant. The list goes on and on," leaving fewer women considered low-risk, said Dr. Jacques Moritz, director of gynecology at Roosevelt Hospital in New York City.
Dr. Mary D'Alton, the Columbia University Medical Center obstetrics chief who recently delivered twins to a 59-year-old woman, has replaced the term "high-risk" with a 1-to-10 scale.
Birth outcomes for older women and those with medical problems "have been better than we would expect," although complications are more common, she said. For example, about half of organ transplant recipients give birth prematurely, although often by just a couple of weeks. "I don't mean to paint a rosy picture, but I would want to paint an optimistic picture," D'Alton said.
Other reasons high-risk pregnancies are increasing:
Older moms. In 2005, there were more than 104,000 births in the United States to women ages 40 through 44, and about 6,500 to women 45 and older. Advanced age raises the risk of birth defects.
Better medical care. For example, women with congenital heart defects used to die young. Those who lived were urged not to get pregnant. Now many such defects can be fixed, and children of women with heart defects are having their own children.
Chronic health problems.
Multiple births, often the result of infertility treatment.
More cancer survivors.
More drugs. Nearly two-thirds of women who gave birth from 1996-2000 took a medication during pregnancy, a large federally funded study found. Of those, nearly 40 percent took a drug whose safety in pregnancy is not established, and nearly 5 percent took a drug potentially risky to the fetus.
The growing prevalence of HIV.