Tag: science

Book Review & Giveaway

Posted in book reviews, Chocolate Babies, Chocolate Lovers, pregnancy, psychology, science by jenapincott on March 18, 2012

This week, the illustrious Pregnant Chicken blog has a review and giveaway of Do Chocolate Lovers Have Sweeter Babies?

Fetal Cells Gone Wild

Posted in Chocolate Babies, Chocolate Lovers, parenting, pregnancy, psychology, science by jenapincott on March 13, 2012

Check out my video and excerpt from Chocolate Lovers on Big Think.

BPA and the Single, Spacey, Sex-Starved Male

Posted in Chocolate Babies, news, parenting, psychology, science, sex by jenapincott on January 31, 2012

Are you having little luck in the search for your soulmate? When you finally meet a woman does she seem disinterested? What could it be? Your breath? Your clothes?

This is not an ad in the personals. It’s the opening line of the commentary in the straitlaced scientific journal, Proceedings of the National Academy of Sciences (PSAS). The authors, neuroscientists Liisa Galea and Cindy Barhain, intend to shock. Why, one wonders, would a man have no luck in love?

Findings from a new study suggest it may be your mother’s dietary exposure to bisphenol A (BPA).

Galea and Barha have all my attention now. Ever since my pregnancy, I have been tracking studies on BPA’s subtle yet shocking effects. One of the most common chemicals in the world, bisphenol A is found in the stuff we use every day of our lives. Soup and soda cans. Water pipes. Computers. Cell phones. Thermal paper receipts. Paper money. Even some baby bottles—at least in the U.S., because they are not banned here.

Much of the trouble with BPA lies in its ability to fool estrogen receptors into thinking it’s estrogen. Imagine a man doesn’t know that the woman he’s marrying is really an alien in drag, and you have a sense of the danger here. BPA disrupts any process that estrogen normally mediates, affecting brain, body, and behavior. It also tinkers with the way genes express themselves, turning up those that would otherwise be turned off or down. BPA exposure has been linked to breast cancer, heart disease, obesity, diabetes, attention-deficit disorder, increased anxiety, a decreased IQ in children and a low sperm count in men.

Pregnant women and new moms should be especially cautious. BPA has been found in umbilical cord blood and in breast milk. It crosses the placenta and flows in fetuses. Young bodies are especially vulnerable to pseudoestrogens. The toxin strikes us moms, too. Researchers worry that BPA may affect women’s brains in a way that alter their maternal instincts. In laboratory studies, BPA-exposed female rats are less likely to nurture their offspring—they lick them less—which in turn affects the emotional and cognitive system of their babies. They become more fearful and anxious.

And now, there’s more.

There is evidence that BPA emasculates males and makes them sexually undesirable. Galea and Barha’s opening lines in PSAS are tongue in cheek—they are describing a new study at the University of Missouri on the effects of BPA on deer mice—but the application to humans is implicit. Adult mice whose mothers were fed a dosage of BPA equivalent to what the USDA deems safe for pregnant women, were, well, different from other males.

“One of the prominent effects of early BPA exposure is that it eliminates a number of sex differences in brain and behavior,” the researchers wrote. It turned out that BPA-exposed males have impaired spatial ability (can’t find their way out of a maze or to their nest, considered unattractive to females). They also suffer from decreased exploratory ability (incurious and easily lost), and overall reduced attractiveness to the opposite sex. They may even smell different from their peers—in rodents, a sign of unhealthiness. Females are disgusted.

It’s not absurd to worry about similar effects of BPA-exposure on our babies. Men are not mice, but there is increasing evidence that BPA affects us as well, and in doses below the below the 50 µg/kg/day safety threshold in the United States. Almost every American pregnant woman (93 percent) has detectable BPA in her body, which is passed on to her fetus. The average BPA body burden of an American is high, alarmingly high, compared to other countries. We love our BPA-enriched Cokes and canned Campbell’s soups.

On a population level, how might BPA affect us? Might boys in the U.S. grow up to have poorer spatial skills—and, because it’s linked, weaker mathematical ability? Might they have little interest in exploring the world, preferring to hang out at home? Might our national temperament become more placid? Because BPA is lined with obesity and heart disease, will we become fatter and more sedate? And what about our sex lives?

Take a look at human history through the lens of hormones, as Harvard University’s Daniel Lord Smail did in his fascinating book, On Deep History and the Brain. Smail introduces a new view in which physiology and culture evolve symbiotically in a process driven by brain chemistry. Caffeine stimulated the body and mind, driving the industrial revolution and the modern corporation. Tobacco help us to focus and be calm. These substances changed the character of society. Now we have environmental toxins such as BPA (and other hormone disruptors such as phthlates and PCBs) that may also change our culture in subtle but very real ways.

BPA: Bad for your manhood. Bad for your sex life. Sensationalistic, sure—but would this get CEOs to pay attention? Hit them where it hurts.

Stubborn pushback—that’s the response from many corporations regarding BPA bans. The chemical is a mainstay in packaging, and to ditch it is disruptive for business. Coca Cola has famously refused to find an alternative. You can find BPA-free cans of beans from brands such as Eden, but not crushed tomatoes yet (in the meantime, buy them in glass jars). Avoid plastics that are marked with recycle codes 3 or 7; they may contain BPA. While Canada, Europe, and even China have banned the use of the chemical in baby bottles, the U.S. has not (although consumer demand has pushed many manufactuers to go BPA-free).

The good news, as I describe in my book, is that there is laboratory evidence that a diet high in folic acid and B12 may reverse at least some of the nasty effects of prenatal BPA exposure. How? One way that BPA tinkers with our systems is by attaching itself to strands of DNA and “turning on” certain genes (removing methyl groups) that are normally turned off—resulting in obesity, cancer, and other nasty effects. This is classic epigenetics—an environmental trigger affects the way that genes behave. Nutrients in green vegetables, beans, eggs, and soy may be protective (in those of us who include enough in our diet) because they turn off genes that BPA otherwise turns on.

Of course, the best protection is to turn corporations off BPA.  That would really be a turn-on for us moms.

 *If you like this blog, click here for previous posts. If you wish, check out my new book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy.

 

 

Starred Review in Library Journal!

Posted in Chocolate Babies, parenting, pregnancy, psychology, science by jenapincott on December 24, 2011

The best holiday gift: DO CHOCOLATE LOVERS HAVE SWEETER BABIES gets a STARRED REVIEW in Library Journal! Many thanks to Library Jrnl and the reviewer, Julianne Smith.

It reads:

What a charm!
Science writer Pincott (Do Gentlemen Really Prefer Blondes?) tackles some myths and legends associated with pregnancy and compares them to peer-reviewed research on the matter. The book covers such questions as: “Do men prefer babies who resemble them?” “What does a baby’s birth season predict?” and “Do bossy broads have more sons?” This is an enjoyable, insightful, and fascinating look at pregnancy that explains what we know and identifies what we don’t. In discussing topics from stretch marks to mama’s boys, Pincott takes a conversational tone, making the science readily available to all readers. An ideal acquisition for public libraries, a great gift for expectant parents, and the perfect choice for the doctor’s waiting room, this winning title deserves some talking up. Way more fun than What To Expect.

LINK

Chocolate Lovers Are Sweeter!

Posted in Chocolate Babies, parenting, pregnancy, science by jenapincott on November 15, 2011

Not long ago, someone emailed me a new study on chocolate and temperament. The study came from a group of psychologists at North Dakota State University and Gettysburg College, and it involved personality differences between people who liked sweet foods versus bitter, spicy, sour, salty, or umami flavors. The researchers wanted to know, “Is having a sweet tooth related to having a sweeter disposition?”

Here’s a sample of what they asked their hundred or so volunteers.

Candy, caramel, chocolate cake, honey, ice cream, maple syrup, pears, raisins, strawberries, and sugar. How fond were they of these dessert flavors?

The volunteers rated their taste preferences on a scale of 1-10.

Following that, they completed an agreeableness scale. That is, they were asked to indicate the extent to which they behave in ways reflective of high (e.g., “have a soft heart”) versus low (e.g., “insult people”) levels of agreeableness.

Pleasingly, the researchers found a significant correlation. People who loved sweets were likelier to be more agreeable.

“Further proof that chocolate lovers would have sweeter babies!” my sender gushed. There’s logic here: If people with a sweet tooth really have a sweeter disposition then women who love sweets might have more agreeable babies because disposition is heritable. Equally valid, people who have sweeter dispositions would have a gentler parenting style, resulting in babies with sweeter dispositions. Ergo, chocolate lovers have sweeter babies. Natch.

Then the researchers took their study to the next level to see if sweet-toothed types not only test as more agreeable, but act sweeter too.

At the end of the session, participants were told that the study was over and that full participation credit would be awarded, thereby relieving them of any further obligations. However, it was mentioned that a colleague in the English department was collecting data on media preferences and was looking for volunteers.

Interestingly, people who had a sweet tooth were more likely to complete the voluntary survey, even though they weren’t getting any extra credit or compensation.

Such sweethearts!

I wonder: does the mere suggestion of sweet food make people act sweeter? Does sweet food make people less angry and aggressive? The researchers claim that metaphors can be predictive about behavior and personality. Because “sweet” in English applies to both taste and disposition, does the correlation still apply in different languages?

How sweet would that be?

How Might Motherhood Prevent Dementia?

Posted in Chocolate Babies, parenting, pregnancy, psychology, science by jenapincott on October 31, 2011

Among the great mysteries — and horrible injustices — of aging is that dementia strikes more women than men. No one knows why exactly.  For years, scientists suspected that the culprit is estrogen. Implicated in memory formation, estrogen levels plummet after women reach menopause.

But here’s the catch.  If low estrogen levels are behind age-related dementia in women, then why did a massive study by the National Institute of Health find that women who had hormone replacement therapy (HRT) were no less likely to experience cognitive decline than women who didn’t have it?

Because not all estrogens are created equal, nor are all brains.  Motherhood may be the missing link.

This comes from an intriguing new study by Cindy Barha and Liisa Galea, neuroscientists at the University of British Columbia’s Brain Research Center.  Barha and Galea knew that the female brain is highly plastic; it literally restructures itself in the course of pregnancy and caring for a baby.  They were curious about whether motherhood might alter the brain in a way that protects against dementia under certain conditions.

One way to explore this is to study middle-aged rats that are genetically identical in every way with the exception of their reproductive lives.  The scientists divided the rats into groups — virgins and mothers — and injected each with a form of estrogen:  estradiol or estrone (the form in HRT).  Later, they looked at the rats’ brain tissue to see whether new cells had formed — a process called neurogenesis — in the hippocampus where memories are formed.  These new cells may reduce the risk of dementia.

It’s interesting, this contest between middle-aged virgins and mothers.  Compared to virgins who had been injected with estrogens (and mothers who hadn’t), the middle-aged mother rats that took the hormone replacement therapy grew significantly more new hippocampal cells.  The mothers — and only the mothers — grew many new neurons when exposed to the estrogens (especially a combination of estrone and 17a-estradiol).  The hormones helped the mothers’ minds to remain malleable.

Why did the mothers have a seeming advantage?  Anther mystery — which Barha and Galea say may be related to an enhanced ability of mothers’ hippocampuses, even late in life, to respond to estrogens.  Such responsiveness may come from hormone exposure during pregnancy or afterward, or enrichment from the experience of mothering.

Interestingly, estradiol’s effect on the brain is mediated by BDNF (brain derived neurotrophic factor levels), which may be higher in mothers than in those who have not given birth. The researchers note that BDNF may help explain an assocation between high levels of estrogen exposure across a lifespan and a decreased risk of cognitive decline and Alzheimer’s disease. Among rats, those who have been mothers have a reduced age-related decline in spatial memory and other cognitive decline.

The scientists conclude:

Therefore previous reproductive experience, which is associated with altered hormone exposure and greater enrichment, can result in higher levels of plasticity in the middle-aged brain and may protect the brain from the deleterious effects of aging in females.

But there’s a very real caveat.  Applied to humans, these findings are still highly speculative. First, the boost would depend on a woman taking hormone replacement therapy, which remains controversial due to its connection with breast cancer.  (Why hasn’t HRT been shown to improve cognition thus far?  It may because a combination of estrone and 17a-estradiol is much more effective than the current regimen of estrone and progestin.)

More importantly, there is no guarantee that new neurons will improve a person’s ability to learn and remember or decrease the risk of cognitive decline.  As Barha and Galhea warn, all that new growth might even lead to a sort of jungle effect if not properly integrated.  There are clearly other factors that determine what properties these new cells will have as they mature.  Do some mothers put their new neurons to use more effectively than others?  No one knows whether or how, but the question is fascinating.  (More research is underway in Barha and Galea’s lab.)

What’s clear is that motherhood results in permanent changes in the brain.  Will we mothers someday benefit cognitively more than childless women from new hormonal therapies? There’s a chance.  Wouldn’t it be marvelous if a cognitive boost later in life would compensate for all the sleepless nights now?

*If you like this blog, click here for previous posts. If you wish, check out my new book,  Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

 

 

 

Who Thinks Pregnant Women are Sexy?

Posted in parenting, pregnancy, psychology, science, sex by jenapincott on September 26, 2011

Early one evening late in my second trimester of pregnancy, I was standing in the dairy aisle of the grocery store, with one hand on my back and the other over the kicking baby in my distended belly. A young man approached me, initiated a conversation about the World Cup, and, casually, asked me if I’d like watch the game with him that weekend. “You’re pretty!” he whispered. I was shocked.

I wasn’t putting out a sexy vibe. (Not at all.) I had assumed that any male attention I receive in late pregnancy, including that from my husband, would be friendly, not sexual. Why would a man who is not the expectant father think pregnancy is sexy? But then other women told me similar stories about how they got hit on in third trimester. So I decided to look into it, and it turns out that a study on sexual attraction to pregnancy has recently come out.

A team of Swedish and Italian doctors, led by Emmanuele Jannini and Magnus Enquist, recruited nearly 2,200 men who had joined online fetish groups such as alt.sex.fetish and alt.sex.fetish.breastmilk. They presented a questionnaire that asked the respondents questions about their preferences for pregnant and lactating women. The survey also asked for the sex and age of each sibling, and whether the sibling is a full sibling or not (half-sibling or adopted child). Most respondents reported both a pregnancy and a lactation preference. The average age at which respondents became aware of their preference was about 18 years.

What Jannini and Enquist and their colleagues were searching for was evidence that there was something special about the upbringing of men that are secually aroused by pregnancy. They knew that a specific stimulus early in life can elicit sexual behavior when that animal reaches sexual maturity. For instance, goats that are raised by sheep are sexually aroused by sheep only. This is called sexual imprinting.

Is it possible that boys that are raised by women who are pregnant for much of their childhoods are unusually attracted to pregnant women?

It turns out, what’s good for the goat is good for the guy. The more exposed a man was to his mother being pregnant and breastfeeding when he was between 1.5 and 5 years old, the more likely he is, as an adult, to be sexually attracted to pregnant and breastfeeding women.

A younger sibling is the key to early exposure. The respondents who eroticized pregnancy and breastfeeding had significantly more younger siblings than expected by chance. Respondents with one sibling were older than their sister or brother in 66 percent of cases. Interestingly, siblings born of a different mother does not appear to be related to respondents’ sexual preferences. Only a boy’s own pregnant mother seemed to leave a sexual imprint.

Freud’s “oedipal phase,” from about 3 to about 5-6 years of age, only overlaps partially with the sensitive period suggested by this study’s data, the researchers are careful to point out. Sexual imprinting is different in that it’s motivated not by sexual drive but because the individual learns what’s normal during a sensitive phase of development and later seeks sexual partners that resemble his (or her) own parents.

What does this mean for women who are pregnant or plan to be pregnant? It means you may be able to predict how attracted your partner will be to you in late pregnancy. Does he have sibling born within five years after him? If so, he’s likelier to be turned on by your pregnant self.

As for the guy I met in the dairy aisle, I’d wager he had a younger brother or sister. I’d bet more on getting this right than the winner of the next World Cup.

 *If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, available October 11,  Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy.

IQ and Fish, the Whole Fish, and Nothing But the Fish

Posted in news, parenting, pregnancy, psychology, science, Sweeter Babies by jenapincott on August 30, 2011

For the nine-plus months of pregnancy, I dutifully downed fish oil pills. I had heard all about the virtues of essential fatty acids (especially DHA, docosahexaenoic acid), known collectively as omega-3s, which are found in fish such as salmon and sardines. These fats are involved in the development of new neurons and help form the cell walls — the structural support — of nerve cells. If the healthy brain is like a sponge, then the brain deprived of omega-3 is like a puddle.

Several years ago, in 2007, an enormous study funded by the National Institute of Health looked at the link between children’s scores on aptitude tests (at ages 6 months to 8 years) and their mother’s prenatal consumption of fish. It turned out that the kids whose moms ate fish more than twice weekly during pregnancy were significantly less likely to have low scores on cognitive tests. Low maternal seafood intake (two or fewer servings weekly) was also associated with increased risk of suboptimum outcomes for prosocial behavior, fine motor, communication, and social development scores. This was a huge deal. The nearly 12,000 expectant women who participated in the study were asked to record how much whole fish they ate, not fish oil supplements.

Naturally, this study — and smaller studies like it involving whole-fish consumption — inspired millions of pregnant women to focus on fish oil.

Problem is, not many of us want to or can afford to eat fish every day. Fears of mercury and PCB contamination are valid (many varieties of fish, such as tuna, have high levels that are toxic to fetuses). It’s not much of a stretch to say that fish oil pills are a better way to get your daily DHA.

But here’s the interesting part. Everyone has assumed that when it comes to omega-3 fatty acids like DHA, the source — whole fish or fish oil pills –shouldn’t matter.  Seems reasonable, but is it?

A few very recent fish oil studies cast doubt:

Results of fish oil pill supplementation range from neutral to negative…

A review of six clinical trials (1280 women in total) involving fish oil pill supplementation during breastfeeding found no significant difference in children’s neurodevelopment: language development (intelligence or problem-solving ability, psychomotor development, motor development. In child attention there was a significant difference. For child visual acuity there was no significant difference.  For language development at 12 to 24 months and at five years in child attention, weak evidence was found (one study) favouring the supplementation.

• At the Women’s and Children’s Hospital in Adelaide, Australia, researchers tracked the children of 2400 women who took DHA-rich fish oil pills in the last trimester of pregnancy. The use of these fish oil capsules compared with vegetable oil cap- sules during pregnancy did not result in improved cognitive and language development in their offspring during early childhood.

Other fish oil pill studies found disturbingly negative results:

• At the Universities of Copenhagen and Chapel Hill, researchers followed 120 Danish women who nursed their babies for four months after birth and took fish oil supplements (or olive oil pills). The children were tested in intervals up to seven years. The higher the early intake, the lower the child scored in speed of information processing, inhibitory control, and working memory tests. Boys whose mothers consumed fish oil had lower prosocial scores relative to the olive oil group.

Meanwhile, these recent studies strengthened the evidence that eating fish is brain-boosting:

• In a study that took place the Arctic, 154 11-year-old Inuit children took standardized tests for memory and verbal learning. Their scores were compared with their levels of DHA present in their cord blood at birth. Children who had higher cord plasma concentrations of DHA at birth achieved significantly higher scores on tests related to recognition memory processing. The source of DH in their mothers’ diets was fish and marine mammals. Intriguingly, the connection with higher test scores remained intact regardless of seafood-contaminant (PCB and mercury) amounts.

* A UK study of 217 nine-year-olds whose mothers had eaten oily fish in early pregnancy had a reduced risk of hyperactivity and children whose mothers had eaten fish (whether oily or non-oily) in late pregnancy had a verbal IQ that was 7.55 points higher than those whose mothers did not eat fish.

This is what I’d love to see: large studies that compare pregnant/nursing fish-eaters versus pill-poppers. Few researchers have tackled this, in part because we assume DHA works the same no matter how we get it, and because DHA from sources other than pills is difficult to measure or isolate.  Interestingly,  a study at the Norwegian Institute of Public Health compared height, weight and head circumference results of newborns whose mothers whose main source of DHA was fish versus pills.  They found that fish-eaters generally gave birth to larger babies while fish-oil-pill-poppers had newborns with a smaller head circumference.

Is it possible that fish consumption boosts IQ, but fish oil pills do not?

It’s dumbfounding, the difference in results between whole fish and fish oil. The researchers that found negative results of supplementation on nursing infants speculated on what goes wrong. It may be that early intervention with fish oil pills results in an “environmental mismatch” between prenatal and postnatal life,” (e.g. the fetus is “programmed” in the womb to live in an environment without abundant DHA and is thrown off when inundated with these fats later on).

Another theory is that the timing in these recent fish oil pill studies is off. The critical period in which fish oil may influence brain growth may be in the first trimester of pregnancy or toward the end of the first year of life — not during the time periods in which women in these studies were taking fish oil pills. It may be that DHA has a “sweet spot” — an optimum level below and above which may be detrimental to the developing brain. Indeed, when researchers look at fish oil pill supplementation and DHA-deficient premature infants, the results are much rosier.

There’s another compelling explanation of why fish oil pills don’t yield the desired results: DHA doesn’t do its magic alone. Nutrients and proteins in fish and seafood, other than DHA, may be  brain-boosters — or at least help us (and our fetuses or babies) to absorb or metabolize DHA better. All the fish oil in the sea can’t compensate for a bad diet.

In the US, a federal advisory recommends that pregnant women not eat more than two servings of fish weekly. This advice may be misguided given that fish such as salmon and sardines are high in DHA but low in mercury. Pop fish oil pills instead; they’re just as good– that’s been the message. But these recent studies point to a different truth.

Thus the case for fish, the whole fish, and nothing but the fish.

Food for thought.

*If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

Can an infection have mind-control properties?

Posted in news, pregnancy by jenapincott on September 29, 2010

I try to be calm as the obstetrician draws my blood to test for toxoplasmosis.

Officially known as T. gondii, toxoplasmosis (or toxo) is a single-celled protozoa transmitted by exposure to cat excrement and by eating raw meat. We can also get it by gardening, eating unwashed fresh veggies and fruit, walking with bare feet on feces-rich soil.

My doctor tests all pregnant women for toxo, as do many doctors in Europe. Infection rates hover around 12 percent in the United States. In Brazil about 67 percent are infected (due to warm climate), in Hungary 59 percent, and in France about 45 percent (for the latter, blame all that steak tartare and pink lamb).

We’ve known for decades that toxo does weird things to the brain because rats infected with the parasite act a bit strange. By strange I mean they’re not only afraid of cat scents, they’re strangely aroused by them. And because they seek out cats, they’re often consumed, and in being consumed they infect the cats, completing toxo’s lifecycle. This is how the parasite perpetuates — by puppeteering. It manipulates rodents to sacrifice themselves to infect other cats and other rats, and so on.

Toxo may also invade and manipulate the human brain, which shares much of the same anatomy and neurotransmitters with rats — although mind control here is different (cats don’t usually eat humans, so there’s no evolutionary pressure on the parasite to tweak its effect on people). Paristologist Jaroslav Flegr of Charles University in Prague found that people with a latent infection tend to be more apprehensive, guilt-prone, self-doubting, and insecure. They have slower reaction times, especially if they also lack a certain blood protein, and three times as likely to get into traffic accidents due to impaired attention or reflexes. Infected women tend to be warmer-hearted, dutiful, moralistic, conforming, easy-going, persistent, and more outgoing and promiscuous. Infected men tend to be more jealous, rigid, slow-tempered, rule-flaunting, emotionally unstable, and impulsive.

Correlation is not causation, as scientists say when fascinating associations like this arise. But toxo may have an impact on personality and behavior because causes slight brain inflammation and alters its host’s levels of dopamine, the neurotransmitter associated with reward and anticipation (and also movement). The parasite does this by producing an enzyme called hydroxylase, which makes dopamine.

Dramatic as this sounds, most people are completely oblivious that toxo haunts their cells. Only pregnant women are commonly tested. And I’m one of them. Because I’m a hypochondriachal life-long cat owner who once worked on a farm, travels extensively, and doesn’t always scrub her veggies vigorously, I’m convinced I’ve been infected.

The nurse doesn’t think it’s an issue. “Not much happens if you’re positive,” she says, and shrugs. Her body language suggests it’s a silly test.

“Unless it’s a recent infection it doesn’t matter. We can tell by the antibodies if you’ve been infected in the last few months. If so, we give you antiparasitic drugs.”

Simple as that.

From a medical perspective, what she says is true. The risk to a fetus depends on the timing of infection and recent infection has the most disastrous consequences. If you happen to become infected with toxoplasmosis while pregnant, or soon before, the parasite or its toxins may cross over the placenta to infect your baby’s nervous system. Babies born to mothers infected in the first half of pregnancy often have shrunken or swollen brains and mental retardation. If infected in the second half, babies may not show symptoms at birth yet central nervous system problems may emerge years later. These babies are at a higher risk of developing schizophrenia — delusions, hallucinations — later in life, likely due to altered levels of dopamine triggered by the parasite.

The nice news is that if you’ve been infected for years before pregnancy you probably won’t pass toxo to your baby, nor will you likely have any obvious signs of infection (although cysts form in the brain). According to Dr. Flegr, only an active infection in the mom suggests a causal link between infection and her baby’s temperament. This is because your immune system usually keeps the parasite in check. But don’t think it’s completely asymptomatic.

In the past decade or so, studies have found that moms with dormant toxo infections have more sons (up to two boys for every girl), and those fetuses develop slightly more slowly than other babies. Perhaps there are other side effects that are undocumented.

Reading up on the science of prenatal infection I get reflective. Viruses, bacteria, and other parasites have always entered us — and some, such as our mitochondrial DNA (originally a bacterium), have become part of us and we can not live without them. Ancient viruses now exist deactivated or defanged in our DNA (in fact, genes from the placenta are thought to be a legacy of ancient viruses) Some viruses may be reactivated, like half-cured villains released from prison, and are thought to be a cause of cancer. Some invaders, initially dangerous, have converted to communalism, such as the thousands of good-guy varieties of healthy gut bacterial that make digestion possible. Strange but true: there are more bacterial than human genes in our bodies.

In a way, pregnancy has made me less fixed on the notion that my self is a singular identity over which I have total control. The fetus is me but not me, and she has changed me in ways I can’t yet fathom. The line between self and other is getting fuzzier.

But as philosophical as I get about self and other, me and microbe, my heart still races when I call the nurse to read my test results.

Negative for toxoplasmosis.

I’m relieved. Truth is, the only parasite I really don’t mind carrying is the baby.

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