Pregnant? Planning to get that way? The scientific research piles up sky-high on what to do and what not to do if you want to have a healthy baby. And it’s not just a simple matter of putting down the crack pipe.
New studies link childhood problems—asthma, ADHD, obesity, and developmental delays—with prenatal exposure to everything from mobile phones to microwave ovens to freeways.
“So many things to which we are exposed are such an integral part of our environment already,” says Berkeley obstetrician Laura Stachel, the associate director of emergency obstetric research in West Africa for the Bixby Center for Population Health and Sustainability.
Magnetic fields, for instance. Magnetic-field exposure is typically associated with microwave ovens, power lines, vacuum cleaners, and hair dryers. The children of women who experience high exposure to magnetic fields while pregnant are three times as likely to have asthma by age 13 as are children of mothers who experience low magnetic-field exposure, according to one Kaiser Permanente study.
And the children of mothers who live within 1,000 feet of a freeway while pregnant are twice as likely to be on the autism spectrum as children of mothers who do not live near freeways, according to a University of California study.
According to a Danish study, children exposed to mobile phones while in the womb are 30 percent more likely to have ADHD by age 7 than children who were not exposed to mobile phones while in the womb.
“Exposure to cellphones prenatally—and, to a lesser degree, postnatally—was associated with behavioral difficulties such as emotional and hyperactivity problems around the age of school entry,” warn the study’s authors.
And you don’t have to be a farmworker to be exposed to pesticides, which researchers link with low IQ and obesity in children, among other problems. We commonly ingest pesticide residue on non-organic produce. From there it enters the blood and breast milk.
“It’s really depressing, isn’t it?” Stachel asks.
Yes, but depression itself raises risks: according to a study released this month, the children of mothers who take SSRI antidepressant medications while pregnant are twice as likely to be on the autism spectrum as are the children of mothers not on SSRIs. That’s jarring news, given another new report claiming that one in every four American women now takes SSRIs.
“Previous studies in rats born to mothers taking SSRI antidepressants showed changes in the young rodents indicating that their brains weren’t properly conducting or processing information,” explains Kentucky physician Rallie McAllister, coauthor of The Mommy MD Guide to Pregnancy and Birth. “Some of the rats displayed abnormal behavior after birth, such as becoming excessively fearful in new situations and an inability to play normally with peers. These are traits that are commonly associated with autism in children.
“Preliminary research suggests that manipulation of serotonin levels in the developing brain of the unborn baby might disrupt the proper development of the sensory-processing regions of the brain, and that maintaining the delicate balance of serotonin appears to be necessary for proper brain maturation,” McAllister says.
Yet another new study suggests that fetuses “know” when their mothers are depressed—and that pregnant women’s changing emotional states affect fetal development.
Some behaviors we know are risky, but maybe not how—or how much. Along with all the other dangers linked to smoking while pregnant, one new study found that the children of women who smoke at least 20 cigarettes per day while pregnant are 30 percent more likely to have been arrested by age 33 than the children of nonsmoking women.
Another study found that men whose mothers smoked while pregnant have a 25 percent lower sperm count than men whose mothers did not smoke while pregnant.
Don’t look down: according to that same study, men who were exposed to smoking in utero also have testicles 1.15 millileter smaller than men whose mothers never smoked while pregnant.
Meanwhile, some behaviors and exposures long considered hazardous might be quite the opposite.
For instance, in-utero exposure to pets might make kids less allergic to pets. A study that examined the levels of Immunoglobulin E (IgE), a type of antibody associated with allergic reactions, found that children born into homes with indoor pet dogs or cats had 28 percent lower IgE levels—associated with reduced allergic symptoms—than children born into pet-free homes.
“The results of this study offer additional support for ‘the Hygiene Hypothesis,’ which holds that children who are around animals and other children early in life are exposed to a wider variety of microbes than children who are not,” McAllister says. “As a result, the exposed children’s immune systems develop a greater tolerance for irritants and allergens. Human immune systems need ‘practice’ fighting bacteria and viruses.”
And despite what we know about fetal alcohol syndrome, one study found that the sons and daughters of women who drink “lightly”—defined as one or two alcoholic beverages per week—are 3 and 2 percent less likely to have “social or emotional difficulties” at age 5 than the offspring of women who drank no alcohol while pregnant.
“There are two possibilities here,” says Keith Eddleman, director of obstetrics at Mt. Sinai Medical Center in Queens, N.Y., and co-author of The Pregnancy Bible. “The first is that maybe there is some protective substance in alcoholic beverages that protects these sons and daughters from social and emotional difficulties. The more likely possibility is that there are other differences between mothers who do and do not consume alcohol during pregnancy that could explain this finding.”
That’s worth noting when confronting any such stats: association doesn’t automatically mean causation. Yes, the offspring of mothers who eat only junk food while pregnant are nearly twice as likely to become “junk food junkies” as the offspring of mothers who eat balanced diets while pregnant—at least according to one Australian study. But who knows what else is going on with women who feast on junk food—or snort coke, smoke heavily, eat conventionally grown produce, take SSRIs, or do pretty much anything at all that might affect their babies?
“Any mother taking cocaine or smoking during pregnancy ... may have other factors that lead to smoking or cocaine use,” says Stachel, whose WE CARE program supplies African hospitals with lighting, equipment and power. “They may be more stressed, more depressed, more angry, eating a worse diet, taking worse care of themselves and their children, for example, than moms not exposed to cigarettes or cocaine during pregnancy.”
So what can we control? From conception onward, should women sip two screwdrivers per week while patting dogs and eating organic sprouts—very calmly, because stress during pregnancy is a famous risk factor? Numerous studies link prenatal stress with ADHD and low IQ in children. A Dutch study found that the babies of women who had high anxiety while pregnant are 9 percent more likely to have skin problems or respiratory illness than those of women who remained relatively stress-free while pregnant.
A likely culprit is the “stress hormone,” cortisol.
“Moms-to-be with high stress levels have higher cortisol levels, to which their unborn babies are exposed,” McAllister explains. “At appropriate levels and in the short term, cortisol can help the body deal successfully with stressful situations. But at higher levels and over longer periods of time, cortisol can have negative effects on the body.”
These effects include interference with immune function, blood sugar, and digestion, as well as increased inflammation and bone loss. This, says McAllister, “is enough to suggest that moms-to-be can benefit from steering clear of stressful situations and environments as much as possible.”
A raft of research confirms this. So relax. Right now. For real. Far from the nearest freeway. Back away slowly from that hair dryer. And put down the cellphone.