Pregnant women face information overload about what's safe to eat

Many have seen someone throw a cold stare in the direction of a pregnant woman ordering a glass of wine or, heaven forbid, smoking a cigarette. But with the list of potentially dangerous foods growing by the day, an expectant mother shouldn't be surprised if a stranger pipes up as she buys a box of mac and cheese.

"Your doctor said you could eat that?" Tut-tut.

Every month that passes brings new studies saying this food is good for you and that food is bad. Pregnant women experience this information overload in exponential terms.

Research over the past few years has added common foods and beverages to the list of items that pregnant women should avoid. Studies have linked maternal consumption of both diet and regular soda with preterm delivery and pre-eclampsia in mothers, higher body mass indexes in infants, and overweight and asthmatic children.

Other studies have found that a fetus may be exposed to arsenic when the mother eats rice, potentially affecting fetal growth. And in July, a widely publicized report found high levels of phthalates, chemicals that in large amounts can impede testosterone production in male fetuses, in macaroni and cheese mixes.

Although none of these foods currently appear on the American Pregnancy Association's Foods to Avoid list, Brad Imler, the organization's president, advises women to exclude them anyway. It's the better-safe-than-sorry school, though some would call it pregnancy paranoia. Unless a woman is constantly monitoring the latest in scientific journals, staying informed of potential dangers is almost impossible. Even then, only experts can tell you which studies and headlines are valid and which are hyperbolic.

"It's really hard to keep up," said Elisabetta Politi, a dietitian at Duke Health. "We're bombarded with so many studies, and many are observational, so we don't know if the food is causing an increased risk or [just] associated with it. But it's the time in life where women are willing to make changes and err on the safe side."

Soda studies vary in samples and methodologies, but each uses large cohorts of mother-child pairs to assess the potential impact of naturally sweetened and artificially sweetened beverages consumed during pregnancy.

Imler says soda should be avoided, full stop. Oster isn't overly concerned. Research that seems to measure soda intake, she says, might actually be measuring a healthy diet, because women who drink soda may be less concerned with eating right, for example.

Ultimately, says Emily Oken, a researcher and professor at Harvard Medical School, there's no reason pregnant women would be harmed by consuming less soda. There are plenty of other reasons not to drink it.

"The occasional beverage is not going to create some lasting harm," Oken said. Nevertheless, she says, water, milk, or tea are always a better way to go. Oster agrees, saying there's a big difference between a soda now and then and several a day. "The biggest takeaway is it's not a good idea to drink five Cokes a day," she said.

Conflicting studies notwithstanding, pregnant women can easily avoid sodas. But the presence of arsenic in rice presents a different challenge, in part because the grain is usually considered a health food.

"We would advise expecting mothers to avoid anything that is connected to arsenic," Imler said. Some chemicals "may not be harmful to an adult-however, developing babies are much more susceptible."

As for boxed macaroni and cheese and other highly processed foods that could have phthalates, it's probably OK to have some every once in a while, but you can be certain no harm will come to you from skipping it. The Grocery Manufacturers Association says the safety of phthalates found in boxed mac and cheese has been reviewed by the Food and Drug Administration, which confirmed "dietary exposure remains well below the permitted safety limits."

So, for those entering the third trimester who are now worried about all the bad things they ate in the past six months, take it easy.