Fruits and vegetables are an essential part of a healthy pregnancy diet, providing vitamins and fiber. Yet some might also come with pesticide residues.
Among women undergoing infertility treatment in the United States, consuming more fruits and vegetables with high amounts of pesticide residue was associated with a lower chance of pregnancy and a higher risk of pregnancy loss, according to a study published in the journal JAMA Internal Medicine on Monday.
Pesticides are pest-killing substances often applied to fruits and vegetables to help protect them -- and us -- against harmful mold, fungi, rodents, weeds and insects. There has been growing concern that exposure to pesticides can be tied to certain acute and chronic human health concerns.
"Most Americans are exposed to pesticides daily by consuming conventionally grown fruits and vegetables," said Dr. Yu-Han Chiu, a research fellow in the department of nutrition at the Harvard T.H. Chan School of Public Health and first author of the study.
"There have been concerns for some time that exposure to low doses of pesticides through diet, such as those that we observed in this study, may have adverse health effects, especially in susceptible populations such as pregnant women and their fetus, and on children," she said. "Our study provides evidence that this concern is not unwarranted."
Yet the findings should be digested with caution, said Janet Collins, executive vice president of science and regulatory affairs for CropLife International, a trade association representing the manufacturers of pesticides. Collins was not involved in the study.
"The JAMA research publication does not show a direct link between pesticide residue intake and pregnancy outcome, as the authors state. This is a hypothesis generating study, and as the authors recommend, we agree that before a definitive outcome can be established the issues require further study," she said in an emailed statement.
How harmful are pesticide residues?
The study involved 325 women between 18 and 45 who were undergoing infertility treatment with assisted reproductive technology at the Massachusetts General Hospital, the researchers said.
The women completed a diet assessment questionnaire and had their height, weight and overall health measured, while the researchers accounted for confounding factors that could influence the study results, including their intake of supplements and residential history.
The researchers analyzed each woman's pesticide exposure by determining whether the fruits and vegetables she consumed had high or low levels of pesticide residues, based on reports from the US Department of Agriculture's Pesticide Data Program, which monitors the presence of pesticides in foods sold throughout the United States.
Some fruits and vegetables with a low amount of pesticide residue include avocados, onions, dried plums or prunes, corn and orange juice. Those with a high amount include fresh plums, peaches, strawberries, spinach and peppers.
The researchers found that, compared with women who ate less than one daily serving of high-pesticide-residue fruits and vegetables, those who ate 2.3 servings or more had 18% lower probability of getting pregnant and 26% lower probability of giving birth to a live baby.