NEW HAVEN, Connecticut – When medical journalist Annie Murphy Paul’s first son was a toddler, she started wondering how personality traits are passed from one generation to the next. So she did what any reporter would do: She delved into the scientific literature and talked to investigators.
Then, in the course of her research, she became pregnant herself.
“I originally wanted to write about the transmission of characteristics and behaviours in families,” Paul, 38, said in an interview over tea and a brownie at a cafe near her home here. “That definitely came out of having my first child and thinking about what I’d want to pass on from my family and from my husband’s family.”
But then, she continued, she became intrigued with the idea that some important characteristics might be passed down in the womb, during gestation. “That struck me as an amazing idea,” she said. “Something between nature or nurture, or really both.”
The idea led to her acclaimed new book, “Origins: How the Nine Months Before Birth Shape the Rest of Our Lives.” Divided into nine chapters that mirror the nine months of Paul’s own pregnancies, it explores the notion that heart disease, diabetes and perhaps other illnesses may have their origins during pregnancy.
This hypothesis is supported by a succession of studies. Some scientists have a hunch that a pregnant woman’s diet and her exposure to various chemicals turn on some fetal genes and turn off others. These switches play a vital role in the life of the adult-to-be, making the child more or less susceptible to disease, including mental illness.
The ultimate goals of such research are twofold: to be able to fine-tune advice to pregnant women and to spot high-risk individuals early on, even at birth. That said, the field is still in its fetal stages.
Still, Paul found the research reassuring. “People often ask me, ‘Did your research make you more anxious about your pregnancy?”’ she said, “but I found just the opposite.” The first time, she added, she did not know what to believe, how seriously to take the warnings that every pregnant woman confronts. It’s worse “to have a little bit of knowledge, just enough to know to feel that you are always doing something wrong.”
“When I delved into the research and talked to scientists,” she said, “I was able to put these findings into context and see the big picture. So that’s what I wanted to do for readers.” (Her sons are now 5 and 1.)
Paul devotes each chapter to an environmental influence that can arise during the corresponding month of pregnancy. For example, she writes about findings that babies born to obese women used insulin less effectively than those whose mothers had weight-loss surgery before pregnancy.
The findings hint that environment in the womb may play a part in diabetes that goes beyond genetics – as does a study finding that rats that binged on junk food were 95 percent more likely than others to have offspring that were disposed to overeat.
Paul also describes methylation, the process by which a cluster of chemicals (a methyl group) sticks to genes and controls whether they turn on or off. Some foods act as methylators; a study of a species of fat mice prone to diabetes and cancer found that when they were put on a diet rich in methylators, their offspring grew up thin and without an increased risk of disease.
This type of research has its origins in the work of Dr. David Barker, a professor at the University of Southampton in England, who connected malnutrition in women with an increased risk of heart disease and diabetes among their adult offspring. His ideas, developed in the 1980s, were widely dismissed at first, but now many of his critics have become colleagues and consider him the father of the field.
Barker’s observations and the more recent experiments on gestational mechanisms are “a terrific combination of medical science coming together from two different directions,” said Dr. Alfred Sommer, emeritus dean of the Bloomberg School of Public Health at Johns Hopkins. His team has found that malnourished Nepalese women given vitamin A during pregnancy had babies with greater lung development, perhaps preventing disease later on.
Paul said that during her first pregnancy, she was scared to eat fish because of potential toxic effects of mercury. During her second pregnancy, she read about a study that found that women who ate little seafood during pregnancy were more likely to have children who scored low on tests of verbal IQ. She started eating sardines – low mercury, high omega-3 fatty acids.
Her biggest critics, she said, have not been scientists but “ordinary women who say that this is going to make women more anxious and that you’re adding to the burden that pregnant women already feel.”
“My answer to them is that the research is real, it’s happening and we are going to keep hearing about it,” Paul said. “We are in a kind of ‘worst of all worlds’ now, with women bombarded by these sensationalized messages from the media. If we can learn more about it and see the big picture, that is better than the other options: Ignoring it or dismissing it or letting scare tactics drive us crazy.”