What's on Tap, Mom?

The day J.J. was born, my loving husband prepared cosmopolitans to celebrate the birth of our first child as well as the fact that I wouldn't have to abstain from alcohol anymore.  (This was back when Sex and the City was big).  Having endured a 36-hour labor, followed by a C-section, I was in no shape to partake, but we still got dirty looks from our nurse as she eyed our vodka.  Honey, couldn't you have gone with the socially acceptable champagne bottle?

I knew from brief Internet searches that while there is "no safe amount" of alcohol to drink during pregnancy, the expert advice on drinking during breastfeeding ran the gamut.  Some lactation specialists actually recommend alcohol to relax the mother and infant, while others think even one drop is too much.  I'm no longer nursing, but let's see if I can find evidence to support my habits retroactively.

Let's put to rest one old wives' tale, that alcohol facilitates nursing.  Multiple studies have found that alcohol actually reduces milk production. In one trial, women who drank a screwdriver produced on average one less fluid ounce compared to when they drank OJ alone. ("The transfer of alcohol to human milk.") So why do some women think alcohol improves breastfeeding?  Well, when milk production goes down, infants suck for longer, creating the impression that they're eating more.  Another, similar study done by the same authors found that 78% of women who consumed alcoholic beer noticed fullness in their breasts after nursing, making them think that they were producing a lot of milk, and lending empirical evidence to the existence of beer goggles.  ("Beer, breastfeeding and folklore.") Finally, infants just like the taste of alcohol-flavored milk.  They will suck down bottles of it, compared to virgin milk. ("Infants suckling responses to the flavor of alcohol in mothers' milk.") So in effect, a nursing mom who drinks is producing Milker Lite -- tastes great, less filling!

Alcohol does enter breastmilk, at the same or higher concentration than in the mother's blood.  One study recruited nursing mothers to "drink as much alcohol as they could manage in the form they preferred in as short a time as possible."  ("Alcohol in breast milk.")  Let's hope their babies had a designated parent.  One enthusiastic mom enrolled in the study twice, getting legally drunk both times.  Based on the alcohol content in her milk, the investigator then estimated that her infant's blood alcohol level would be 0.006% -- meaning Baby could drive Mama home. 

What most moms want to know is whether this miniscule exposure will affect development.  And here the research is as muddled as a mint julep.  One observational study of 400 nursing women found that mothers who drank an average of one drink a day had children who scored slightly lower on a motor development scale at 12 months of age.  There were no differences in mental development.  ("Maternal alcohol use during breast-feeding....") A follow-up study of 915 women found that the more mothers drank, the higher their children scored in general intelligence, motor development and personal-social development at a year and a half.  ("Alcohol, breastfeeding, and development at 18 months.") It's pretty unlikely that alcohol is good for babies, so there are probably unmeasured factors that influenced the results of both studies.  The other flaw in these studies was that few women drank more than 2 drinks a day, so the effects of truly excessive drinking are unknown -- and would be hard to sort out from generally bad parenting.


Based on these iffy studies, the American Academy of Pediatrics, ever the party-poopers, state in their guidelines, "An occasional, celebratory (what, postpartum women can't wallow?), single, small alcoholic drink is acceptable (if you must), but breastfeeding should be avoided for 2 hours after the drink."  For the anally compulsive, a nomogram is available to tell you when it is safe to nurse after a night of carousing.*  ("Alcohol and breastfeeding: calculation of time to zero level in milk.") I have very helpfully reproduced it here, so you can tuck it into your little black bag before hitting the clubs:

According to this chart, any alcohol would have disappeared from my milk 2.36 hours after one drink.  Dang it, I could have downed 6 shots a day on my every 4 hour nursing schedule!


But I didn't.  So, please, those dirty looks are completely uncalled for.


*By the way, girls, no need to pump and dump.  Alcohol will diffuse out of your milk at the same rate as it does out of your blood.

Did I Nuke my Baby's Lungs?

 Did wireless make my Jojo wheeze?

The news media has been trumpeting a study performed by Kaiser Permanente, reporting a strong link between exposure to magnetic fields during pregnancy and the development of childhood asthma.  ("Could microwaves be associated with children's asthma?")  So now pregnant women can't nuke their Irish coffee?  Seriously, we moms already have to give up a zillion things when we're preggers; do you really want to tell us hands off our cell phones and hairdryers?

The study did have its strengths.  ("Maternal exposure to magnetic fields during pregnancy in relation to the risk of asthma in offspring.") The researchers asked over 700 pregnant women in their first and second trimesters to wear a monitor to measure their exposure to magnetic fields for 24 hours.  They then followed their offspring for up to 13 years to see if they were diagnosed with asthma.  So the good things about the study were that they measured magnetic fields objectively, and the doctors diagnosing asthma were unaware of the level of exposure in the mothers.  The researchers also controlled for some, though not all, risk factors for asthma, such as smoking during pregnancy.  What they found was a clear dose-response relationship between magnetic field exposure and asthma in children.  Those in the top 10% of exposure level had children with an almost 50% chance of developing asthma.

Pretty convincing, huh?

Not so fast.  Why did the investigators study women in both their first and second trimesters, when lung development occurs primarily in the second trimester?  I'll tell you why first trimester women were enrolled: This research group has studied the effects of magnetic fields not only on asthma, but also on the rate of miscarriage and sperm quality (in men, of course).  In fact, all three of the studies they published have found a harmful association between magnetic fields and their outcome of interest.  So what does this mean?  That magnetic fields cause a wide array of harmful effects?  Or that lightning struck three times for this research group?  And why did this group choose asthma as an outcome to study anyway?  There are no other studies showing a link, nor have magnetic fields been shown to cause asthma in animals.

Here's what I think:  The investigators probably examined a number of outcomes, but they only reported the finding that was "statistically significant."  In studies, we say that a finding is "statistically significant" when there is a less than 5% chance that it was just a fluke, and therefore a greater than 95% chance that the result is "real."  But what if you are looking to see if magnetic fields are associated with two different outcomes, say asthma or low IQ?  Then you actually have a 10% chance that at least one of the outcomes will be associated in a "statistically significant" way with the exposure.  If you are looking for 20 different outcomes, the chances of finding a bogus, statistically significant result is up to 64%.  And here's the kicker -- as an investigator, you are not required to reveal how many hypotheses you tested.  All you have to do is publish the one result that comes back positive.  And forget publishing a negative result, unless it's to debunk someone else's positive result.  I doubt the Archives of Pediatrics and Adolescent Medicine would have as their lead article, "Maternal exposure to magnetic fields dudn't do nuttin'."

To be fair, I don't know how many hypotheses these researchers tested.  But when I asked the lead author of this study this question, this was his email response:  "This was the first prospective study of EMF [electromagnetic field] health effect.  For prospective studies, one can study multiple outcomes. But we are currently interested in conditions that have had....increase without any apparent explanation."  So all you women who are in the family way -- take this scary study, along with your microwaved Irish coffee, with a grain of salt!