A study by French researchers shows that air pollution, and in particular fine particle pollution, can increase the length of the phase preceding ovulation. This could alter a couple’s chances of conceiving a child.
Several studies have already shown that air pollution, in particular nitrogen dioxide, which is responsible for the formation of fine particles in the ambient air, has an impact on the health of the mother and her future child. The risk of pre-eclampsia in pregnant women, low birth weight of the baby, altered lung function, neurodevelopmental disorders and the risk of high blood pressure have been highlighted by several scientific studies.
A new study, conducted by Inserm researcher Rémy Slama of the Institute for the Advancement of Biosciences and published in Environmental Pollution, shows that fine particle contamination has negative effects on female fertility by altering the menstrual cycle.
An increase in the length of the follicular phase
What are the effects of fine particle pollution on the menstrual cycle? To determine this, researchers conducted hormone measurements in the urine of 184 female volunteers over a complete menstrual cycle. They also measured the levels of air pollution to which they were exposed in the month before the start of their cycle, including fine PM10 particles, that is, particles smaller than 10 micrometers, and the concentration of nitrogen dioxide.
They then observed an association between the concentration of fine particles in the air and the duration of the follicular phase of the cycle, i.e. the phase prior to ovulation. The follicular phase increased on average 0.7 days for each average increase of 10 micrograms per cubic meter of nitrogen dioxide concentration. Each average increase of fine particles per cubic meter of concentration prolongs on average by 1.6 days the follicular phase of the cycle. However, the length of the luteal phase, which follows ovulation, does not increase the total length of the menstrual cycle.
Influence on fertility
“These results are consistent with more fundamental data suggesting that air pollution can disrupt the axis that controls the menstrual cycle, and stress hormones such as cortisol ” explains researcher Rémy Slama in a statement.
But the latter prefers to warn: “This is an original work that generates a new hypothesis. It will probably take some time to be refuted or confirmed in larger samples of the population, given the cost and effort involved in such studies.” However, the authors of the paper say their conclusions confirm the results of some previous studies suggesting that adult exposure to air pollutants may have an impact on fertility.