Can Pesticides Affect Pregnancy?

A new study was released that I know a lot of you are going to be concerned about. It seems that eating fruits and vegetables that are known to have high pesticide residues could make it harder to get pregnant.

There’s bound to be a lot of hand-wringing over this in certain corners of the internet. So, I want to put these findings in perspective for those of you who are trying to conceive as well as anyone who is just generally concerned about pesticides and their effects on health.

The study was overseen by Dr. Jorge Chavarro, an expert in reproductive medicine at the Harvard School of Public Health. Some years ago, Dr. Chavarro and his colleagues published a book called the Fertility Diet, which promoted a dietary regimen that was supposed to increase your chances of getting pregnant. I reviewed the Fertility Diet in a previous podcast.

This latest study looked at several hundred women who were undergoing treatment at a fertility center in Boston. These women filled out a questionnaire about their dietary habits prior to seeking treatment. The researchers analyzed these questionnaires to see what kinds of fruits and vegetables these women were eating, and exactly how much.

They wanted to see whether or not there was a link between estimated pesticide exposure and fertility. And sure enough, they found one. The women who had the highest estimated pesticide exposure from fruits and vegetables were less likely to get pregnant than those with the lowest estimated exposure. And it’s not too hard to imagine why this might be. Many (but not all) pesticides are what we call endocrine disruptors; they interfere with reproductive hormones. This has been widely observed in fish, frogs, and other wildlife, and confirmed by lab studies.

This new study, although it cannot prove a causal link, certainly raises the alarm that we may have underestimated the potential harm of typical pesticide exposure to certain vulnerable populations, such as those trying to conceive, pregnant women, and unborn babies.

Fruits and Vegetables with Highest Pesticide Residue

You’ve probably heard about the Dirty Dozen. This is a list of fruits and vegetables that are known to have high pesticide residues. They include things like strawberries, apples, spinach, grapes, and bell peppers. Other fruits and vegetables, such as bananas, avocado, onions, and cabbage have lower pesticide residues. Whether or not a vegetable has a high pesticide residue depends on a number of factors: how they’re grown, what kinds of pests get after these particular plants, and what chemicals are typically used to control them, and what part of the plant we typically eat.

The Environmental Working Group has estimated that by avoiding the Dirty Dozen, you can reduce your exposure to pesticides by up to 80%. You could buy organic for those particular fruits and vegetables. But if organic is not in your budget, or at your grocery store, there are plenty of other fruits and vegetables that you can choose instead.

Others have questioned the value of this advice. Dr. Carl Winter, a food toxicologist at UC Davis has pointed out that even if you do eat the Dirty Dozen, the amount of pesticides you'd be exposed to would be far below the threshold for unsafe exposure.

Dr. Winter worries that unfounded fears about pesticide exposure could cause people to eat fewer fruits and vegetables and that’s the last thing we want to happen. As I’ve said before, the benefits of eating plenty of fruits and vegetables far outweigh the potential risk of the pesticides you might be exposed to.

This latest study certainly calls this advice into question. But I want to add a little bit of perspective, as well as some suggestions on how you might respond to this information.

Fertility Rates and Pesticides: Putting it in Perspective

First, keep in mind that all of the women in this study were seeking advanced fertility treatments. These were women who were having difficulty getting pregnant for reasons other than their dietary habits. It’s likely that there were already some endocrine issues going on and perhaps this made them extra sensitive to levels of exposure that would not affect the general population.

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Secondly, the pesticide exposure was indirectly inferred. They didn’t analyze the women’s urine or blood to look for traces of these compounds. They were basing their analysis on the women’s own estimations of how often they ate various foods in the past and USDA data on the general food supply. As Dr. Winter pointed out in an email to me, this particular data doesn’t specify which pesticides were likely to be present or in what amounts. And we haven’t yet studied whether counseling women to change their dietary patterns will improve fertility rates.

And finally, to echo Dr. Winter’s previous concern, we don’t want this research to scare women into not eating fruits and vegetables—or to worry that eating too many apples or strawberries is going to prevent them from getting pregnant. As Dr. Chavarro notes in the Fertility Diet, a diet rich in fruits and vegetables is supportive of general health and fertility. (And the data that show that are based on people eating mostly conventional produce.)

Eat lots of fruits and vegetables, no matter what.

To Limit Pesticide Consumption, Here’s What You Can Do

If you’re worried about the potential effects of pesticides on your fertility or your health, you have a couple of options that don’t require you to avoid healthy foods or run up an unnecessarily high food bill. Here’s how I would approach it if organic options are not readily available or in your budget.

1. Step 1: Eat lots of fruits and vegetables, no matter what.

2. Step 2: Load up on the fruits and vegetables known to be low in pesticide residues. These include peas, beans, cauliflower, onions, avocados, bananas, grapefruit, and cabbage.

3. Step 3: For apples, grapes, peppers, spinach, strawberries, and other fruits and vegetables that are likely to have higher pesticide residues, limit your consumption to one serving a day.

4. Step 4: Wash your fruits and vegetables thoroughly to remove surface residue. My favorite method is to spray them with plain white vinegar, rub them vigorously, and rinse with plenty of clean water.

5. Step 5: Limit the use of pesticides in and around your home and garden.

Environmental Working Groups Resources:

• Dirty Dozen
• Clean Fifteen

Image of pregnant woman and fruit © Shutterstock