Time to pregnancy and exposure to pesticides in farmers in the West Bank, occupied Palestinian territory: a 1-year follow-up of newly married couples

Abstract

Background Pesticides have been associated with a reduction in reproductive capacity. In the occupied Palestinian territory, agricultural work is a family enterprise rendering all members at risk of occupational or paraoccupational exposure. We investigated the effects of pesticide exposure on couples' fecundability (probability of conception in a menstrual cycle). Methods 331 newly married couples (women aged 16–66 years and men 15–42 years) from two Palestinian villages in the Hebron Governorate, West Bank, who were attempting to conceive for the first time during 2005–07, were identified from the Thalassaemia Centre, Hebron, where all individuals who are planning to marry are obliged to register. Couples were followed up prospectively from marriage until pregnancy or a maximum of 12 months. We assessed male exposure on the basis of current use of pesticides by creating a time-dependent exposure variable covering the month of follow-up and the 2 months before the follow-up. In women, work in farming was used as an indicator of exposure. We estimated the adjusted fecundability density ratio (aFDR) with discrete proportional hazards regression. Covariates for the multivariable model, selected on the basis of a-priori assumptions, were coital frequency reported by the women, and for men and women body-mass index, age and education, and village of residence. SPSS (version 16.0) and Stata (version 10.0) were used for statistical analyses. The study was done in accordance with the current revision of the Helsinki Declaration and was approved by Hebron University. All participants provided written informed consent and were informed that participation was voluntary and that they could withdraw from the study at any time. Findings Follow-up was completed in all but four couples. 288 (87%) of 331 couples became pregnant during follow-up with a mean fecundability of 0·20 (95% CI 0·19–0·22). Fecundability was moderately reduced in association with pesticide exposure in men (aFDR 0·72; 0·52–1·00) and farming in women (0·68; 0·42–1·09). Interpretation Exposure to pesticides was associated with reduced fecundability in couples. Furthermore, in the Palestinian population, the first menstrual cycle at risk could be defined accurately because premarital sex or having children outside of marriage are cultural and religious taboos and because all couples stated that they intended to start attempting to conceive immediately after the wedding. The main limitation was that pesticide exposure was reported as crude data, which could lead to an underestimation of the effect of pesticide exposure. Further research with improved exposure data is warranted. Funding Norwegian Programme for Development, Research and Education.