Pesticides and Pregnancy

---

Pesticide exposure and self-reported gestational diabetes mellitus in the Agricultural Health Study, by T.M. Saldana and colleagues. Diabetes Care 30:529-534, 2006.

What is the problem and what is known about it so far?

About 4% of pregnant women get diabetes only during the time that they carry their baby. This is called gestational diabetes mellitus (GDM). After the baby is born, GDM goes away, but about one-half of these women get type 2 diabetes later in life. For this reason, scientists think of GDM as an early stage of diabetes.

Many studies have shown that people with diabetes die more often when they come in contact with pesticides. Pesticides are chemicals used by farmers to control for any kind of pest (weeds, insects, bacteria, etc.) and to help their crops grow. Many studies have also shown that contact with pesticides makes things happen in the body that cause people to get type 2 diabetes.

Why did the researchers do this particular study?

While studies have looked at whether pesticides and diabetes are related, no studies have looked at a link between pesticides and GDM. Because so many women with GDM get type 2 diabetes later, it is important to find things in women’s lives that cause GDM.

Who was studied?

A total of 32,171 wives of farmers answered questions about many topics. The wives were only asked questions if their husbands used pesticides for farming. All of the women lived in either North Carolina or Iowa.

How was the study done?

Every 3 years, people in Iowa and North Carolina have to ask to be allowed to use pesticides. Between 1993 and 1997, 32,171 spouses of the people who asked to use pesticides answered a survey by mail or telephone. After looking through the answers to the surveys, scientists found 11,273 pregnancies to study. Each pregnancy took place in a different woman. Scientists looked closely at answers to questions about pesticide use during the first 3 months of being pregnant. Women who came in contact with pesticides during this time were split into groups. One group of women only came into contact with pesticides by touching plants that were grown using pesticides. Another group only applied pesticides to their garden or inside their house. A third group of women came in direct contact with pesticides while helping with farming. Scientists compared the number of women in each group with the number of women who got GDM.

 What did the researchers find?

A total of 4.5% of the women studied got GDM. Women who came in direct contact with pesticides while farming were twice as likely to get GDM.

What are the limitations to the study?

Women who answered the survey had to base their answers on memory, and sometimes people forget things over time. Many studies, though, show that when it comes to being pregnant, women remember things very well. Also, even though the scientists tried to leave women out of the study if they had type 2 diabetes already before being pregnant, some women who already had type 2 diabetes might have wound up in the study.

What are the implications of the study?

Some pesticides used to keep insects away were found to be very connected with GDM. Pregnant women should be careful about these chemicals. Also, there were two other kinds of pesticides that were used more often by women who got GDM, called 2,4,5-T and 2,4,5-TP. Both of these pesticides often have dioxin in them. Dioxin is a chemical that hurts people in many ways. People most often come in contact with dioxin by breathing polluted air, by handling pesticides or garbage as part of their job, and by eating meat, dairy, or fish. Many studies have linked dioxin with type 2 diabetes. This study shows that dioxin is also connected with GDM.

FOR MORE INFORMATION

Gestational Diabetes

Pollutants and Diabetes

Dioxins