Each year about 4 million babies are born in the U.S., the vast majority of them healthy.  Thanks to advances in medical research and improved health care, most births in the U.S. result from low-risk “uncomplicated” pregnancies.  But by some estimates, each year nearly 1 million expectant moms in America experience some sort of pregnancy-related complication.  Problems can range from easily treated vitamin deficiencies to more complex conditions like preeclampsia, which can be life-threatening to both mother and baby.  Fortunately, you can take steps to learn more about potential risks and prevent or reduce their impact. 

“One of the most important things you can do is be healthy before you even become pregnant,” says Dr. Catherine Spong, chief of the pregnancy and perinatology branch at NIH’s National Institute of Child Health and Human Development.  “Whatever medical conditions you have, try to optimize their therapies before you become pregnant.  If you have diabetes, get it under control.  If you can avoid being overweight before pregnancy, that’s quite beneficial.  And be sure to start your vitamins early, have an active lifestyle and eat healthy foods.”

Proper nutrition is always important, but some nutrients are especially critical for a healthy pregnancy.  One of the most essential is the B vitamin folate, or folic acid.  Taking folic acid supplements at least 1 month before and throughout the first 3 months of pregnancy can lower a baby’s risk for certain serious birth defects by as much as 70%.  These common birth defects—known as neural tube defects—often arise before a woman even knows she’s pregnant.  That’s why the U.S. Public Health Service now recommends that all women of childbearing age receive 400 micrograms of folic acid every day. 

Several other nutrients play a key role during pregnancy.  You need iron to make healthy red blood cells.  Calcium aids bone growth in the unborn child and helps to prevent bone loss in the mother.  Both of these nutrients, as well as folic acid, are found in prenatal multivitamins.

Nutritional deficiencies are often simple to address, but other prenatal complications pose greater challenges.  Obesity is a common risk factor for several pregnancy-related complications, including preeclampsia, preterm birth and gestational diabetes.  Problems in a previous pregnancy can also be a good indicator of how later pregnancies might progress.  “However, about 40% of the pregnant population at any given time has never had a child, so it’s very difficult to know what their risk is,” Spong says.  A woman’s age and pre-existing medical conditions also affect her risk. 

When thinking about risk factors and complications, though, it’s important to keep things in perspective.  Dr. James M. Roberts, professor and vice chair of research in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine, says, “When we talk about a high-risk situation—as with preeclampsia—we’re really only talking about 3-5% of pregnant women getting the disease.  The vast majority of women do not.”

While only a small percentage of expectant mothers develop preeclampsia, its consequences can be dire.  It is the leading cause of maternal death worldwide.  Thanks to widespread prenatal care, women in the U.S. have only a small risk of dying from the condition.  “Still, it’s a substantial cause of deaths for babies, with death rates about 5 times higher for preeclampsia than for non-preeclampsia babies,” says Roberts.  He and other researchers have also found that preeclampsia greatly increases a woman’s risk for developing heart-related problems later in life.

Preeclampsia is marked by high-blood pressure and protein in the urine.  Currently, the only certain cure is delivery of the baby.  Roberts and scientists at 14 sites across the country are now in the midst of an NIH-funded clinical study to see if the risk of preeclampsia might be reduced by taking vitamins C and E early in pregnancy.  The study is expected to involve 10,000 women by the end of 2007.  “We don’t have the answers yet,” says Spong, the study director at NIH.

Other NIH-funded clinical trials have focused on preterm birth, which occurs in over 12% of U.S. births.  It arises when a baby is born at least 3 weeks shy of a full 40-week pregnancy.  Premature infants face several health challenges, including breathing difficulties and the potential for lifelong medical problems.  “Up until a couple of years ago, we could identify women who were at highest risk for delivering preterm, but we didn’t have anything to really prevent it,” Spong says.  “It was frustrating.”

In 2003, an NIH-funded clinical study identified a promising treatment for women who have already had a preterm birth.  Weekly injections of the hormone progesterone significantly reduced the likelihood of later preterm birth for these at-risk women.  An ongoing clinical trial is now testing whether progesterone might also reduce preterm births in first-time pregnancies.

To Spong, a healthy pregnancy isn’t necessarily one that’s free of complications.  “To me, a healthy pregnancy is one where any medical conditions are well-controlled, so they cause no lasting harm to mother or baby,” she says.  “I’ve had patients with severe diabetes, but if it remains very well-controlled during pregnancy, the outcome can be positive.”

It’s important to see your doctor regularly throughout pregnancy, so that complications can be caught early, and their impact minimized.  “A healthy pregnancy is one where, in the end, both the mom and baby do well,” Spong says.