It was on the cover of The New York Times Book Review. And the cover of Time Magazine. Suddenly, the obscure science of “fetal origins” is getting popular, in the pages of a new book called “Origins: How the Nine Months Before Birth Shape the Rest of Our Lives.”



Written by science journalist Annie Murphy Paul, "Origins" explores the still-murky but growing research into how the environment in the womb can affect a baby’s life ever after -- including the life of the mind. A few questions for the author:



Q; In "Origins," you describe myriad ways that the prenatal environment appears to influence the fetus. What do we know about the effects of the womb on the brain?

A: Fetal origins is very much an emerging science, so we know less than

we would like about the effects of the prenatal environment on the

brain. We do know, of course, that the brain is formed during the nine

months of gestation, and that a number of influences during this

period--chemical exposures, stress, depression, drug and alcohol use,

nutrition--can have effects on the brain, showing up in things like

measures of neural conduction speed, tests of cognitive ability, and

IQ scores.



Q: Many pregnant women worry that their own emotional state, particularly stress, will affect the fetus. How would you sum up the findings on that?

A: The findings on the effects of prenatal stress are twofold. It's

fairly well established that traumatic stress--severe,

life-threatening stress, like that experienced in a natural disaster

or war--is associated with a higher risk of premature delivery, low

birth weight, and in some studies, birth defects. Chronic stresses

like those associated with poverty and discrimination may also have

deleterious effects. Moderate stress, however--the everyday hassles

experienced by your typical working woman or woman caring for other

children--actually appears to accelerate fetal brain development,

leading to faster neural conduction speed as infants and higher scores

on tests of cognitive ability as toddlers.



Q: And what is known about the possible origins of mental illness in the womb?

A: A number of studies on different populations suggests that severe

prenatal stress or malnutrition, particularly in the first trimester

of pregnancy, is associated with a higher risk of schizophrenia among

offspring. Higher rates of this mental illness have been found, for

example, in individuals whose mothers were pregnant during the Nazi

siege of Holland during World War II, during the famine that followed

China’s “Great Leap Forward,” and during the Arab-Israeli War of 1967.

A more speculative theory is that women's own mental states of

depression or anxiety affect the offspring's own likelihood of

developing mental illness, perhaps through the effects of the stress

hormone cortisol. Dr. Catherine Monk at Columbia University is doing

fascinating work, measuring the responses to stress exhibited by

fetuses of depressed and non-depressed women. She believes that

intrauterine conditions may be a "third way" that mental illness is

passed down in families, along with genes and parenting behaviors.



Q: One fascinating theory suggests that the womb may be the arena of a fight between the fetus's heart and its brain for resources. How does that work?

A: A theory originally put forth by British physician David Barker (and

long known as "the Barker hypothesis") proposes that when a fetus

receives insufficient nutrition, it will "make the best of a bad job"

by diverting most of the nutrients it does receive to the organ most

critical to its survival: the brain. This act of triage allows it to

survive to be born and perhaps even grow into middle age--but at some

point the early deprivation experienced by the heart and other organs

shows up in increased rates of heart disease and other illnesses.



Q: You mention that the prenatal environment may account for something like 20% of IQ. Really? And how best can we make smarter babies?

A: To be more precise, a study published in Nature by researcher Bernard

Devlin and his coauthors found that in their analysis of twin studies

of IQ, the intrauterine environment accounted for 20 percent of IQ

similarity between twins, and genes for only 34 percent. Devlin's

point was that in drawing conclusions from such studies (which were

used to buttress the assertions in the book "The Bell Curve," for

example), we must take into account not only genes and childhood

environment, but also the very FIRST environment that twins share: the

womb.



In terms of making smarter babies, the best advice to pregnant women

is to eat a wholesome diet, refrain from drinking alcohol and using

drugs, protect yourself from environmental toxins, and try to

alleviate excessive stress. There's some preliminary evidence that

physical exercise by the pregnant woman may promote offspring's

intelligence, and it can't hurt. But forget about playing Mozart to

the fetus and other "prenatal education" products--they won't increase

intelligence and may even be harmful.



Q: There's also a theory that links the prenatal environment and homosexuality. How would that work?

A: It's a well-established finding that homosexual men are more likely to

have older brothers. The theory--and it's still speculative--is that

the body of a woman carrying a male child generates antibodies in

response to her fetus which stay on in her body after she gives birth.

When she becomes pregnant again with another male child, those

antibodies affect the developing brain of the fetus in ways that

incline the offspring towards homosexuality. It's an intriguing theory

but one that needs a lot more substantiation.



Q: What do you say to mothers who protest that "fetal origins" research is just more reason for even more maternal guilt?

A: I would say, first: I totally sympathize. I was pregnant when I

researched and reported "Origins," and I had to work through a lot of

my own anxiety and guilt. What I came to realize is that the science

of fetal origins is growing so rapidly that we are only going to hear

more and more about how prenatal conditions affect later health and

well-being--so we need to find a more positive and productive way of

thinking and talking about these findings, one that neither dismisses

them out of hand nor makes us crazy with worry. I also found the

excitement and optimism of the fetal-origins researchers I talked to

rather contagious: they see pregnancy as a scientific frontier, a

wonderful new opportunity to head off public health problems like

obesity and diabetes. So I came, over the months that I was writing

"Origins," to see pregnancy in that light--as a physical, emotional,

and intellectual adventure.