A study published on October 16 in
the journal Environmental Health shows that women's exposure to chlordecone is associated with a longer time to conception.
Obtained from data collected in Guadeloupe from 668 pregnant women between November 2004 and December 2007, these results strongly suggest that this insecticide (widely used in the French West Indies until its ban in 1993) could harm women's fertility, as previously indicated by experimental studies in animals.
Several studies have shown that chlordecone exposure is associated with adverse effects on pregnancy (increased risk of prematurity[1]) and child development (poorer scores on cognitive tests and behavioral difficulties following prenatal and postnatal exposure[2]), particularly in the French West Indies, where this pesticide was widely used until its ban in 1993 due to its high toxicity and where it has persistently contaminated agricultural land.
A new study published by a team from Inserm at the Institute for Research in Health, Environment and Work (Inserm/University of Rennes/French School of Public Health) in the journal
Environmental Health on October 16 shows that this pesticide increases the time needed to conceive a child, a recognized indicator of couple fertility.
These results were obtained using data from the Timoun mother-child cohort, collected between November 2004 and December 2007 from 668 pregnant women, interviewed during check-up visits in the second or third trimester of pregnancy at the University Hospital of Guadeloupe and at the hospitals of Basse-Terre and Pointe-à-Pitre, as well as in prenatal care services. At the same time, samples were also taken to measure chlordecone concentration in their blood.
Result:
"The more women were exposed to high levels of chlordecone, the longer it took them to conceive their child", summarizes Luc Multigner, emeritus research director at Inserm and co-author of the study.
To analyze the link between chlordecone exposure and difficulty conceiving, women were classified into four groups according to their level of exposure to the insecticide. The research team observed that the most exposed women, whose blood chlordecone concentration exceeded 0.4 µg/l, took longer to become pregnant and that their chance of achieving pregnancy during a menstrual cycle was reduced by about a quarter (between 24 and 28% for the two most exposed groups).
Due to lack of exposure measurements in partners, it is difficult to attribute this increased time to conception solely to women.
"However, previous studies in Guadeloupe in men, at exposure levels similar to those of women, showed no effect on sperm quality or reproductive hormones[3]
. In laboratory animals, chlordecone has already been associated with decreased fertility in females[4]
. In light of this work, our study supports the hypothesis that this pesticide could impair women's fertility", adds the researcher.
Although the observed association is significant, the study does not formally establish a cause-effect relationship. Indeed, female infertility can have multiple origins, such as polycystic ovary syndrome or endometriosis for example.
"The Karu-Fertil study[5]
, which is ongoing in Guadeloupe[6]
, will help clarify the links between chlordecone exposure and female infertility", explains Ronan Garlantézec, professor of public health at the University of Rennes and scientific lead of this study.
"In the meantime, the results we just published already support the need to continue public health efforts to reduce chlordecone exposure, particularly among women of childbearing age", concludes Ronan Garlantézec.
Ronan Garlantézec discusses the conclusions of this study in a video produced by the University of Rennes.
Notes:
[1]
https://presse.inserm.fr/exposition-au-chlordecone-et-prematurite-nouvelles-donnees/10687
[2]
https://presse.inserm.fr/lexposition-pre-et-postnatale-au-chlordecone-pourrait-impacter-le-developpement-cognitif-et-le-comportement-des-enfants/66616
[3]
https://journals.lww.com/epidem/fulltext/2006/11001/exposure_to_chlordecone_and_male_fertility_in.989.aspx
[4]
https://pubmed.ncbi.nlm.nih.gov/6192033/
[5] The Karu-Fertil study is based on two complementary approaches: an epidemiological study targeting women aged 18 to 39 consulting for couple infertility at the University Hospital of Guadeloupe, and a sociological approach targeting women participating in the epidemiological component and healthcare professionals managing couple infertility in Guadeloupe. This study, funded by ANR and the Fondation de France, brings together four partners: Inserm, the University Hospital of Guadeloupe, the National Institute for Demographic Studies, and the Pasteur Institute of Guadeloupe.
[6]
https://anr.fr/Projet-ANR-22-CHLD-0001