P-736 Elevated levels of ambient air pollutants increase the primary sex ratio in human embryos

AbstractStudy questionAre there any associations between ambient outdoor air pollution and the primary sex ratio (PSR)?Summary answerShort-term exposure to increased PM10, PM2.5 and NO2 levels were significantly associated with higher PSR.What is known alreadyPSR estimates represent a backward extrapolation from data based on spontaneous or induced abortions, fetal deaths or live births and are usually male-biased. A recent study, analyzing 3- to 6-day-old embryos derived from assisted reproductive technology (ART) procedures, showed that the sex ratio at conception is unbiased (0.5). Epidemiologic studies of air pollution on secondary (birth) sex ratio showed that higher levels of particulate pollution were associated with increased rates of female birth. However, a direct association between urban levels of air pollutants and PSR has not been reported.Study design, size, durationA retrospective cohort study was carried out to assess the impact of long- or short-term exposure to six ambient outdoor air pollutants (particulate matter, PM10 µm and PM2.5 µm; SO2; CO; NO2; O3) on PSR (XY/XX) of couples undergoing their first IVF cycle for preimplantation genetic screening (N  = 337). Data was from fixed air quality monitoring stations across the city between January 2014 and December 2018. Embryos with sex chromosome abnormalities were excluded from the analysis.Participants/materials, setting, methodsAverage concentrations of the pollutants for the 90 (long-term exposure)...
Source: Human Reproduction - Category: Reproduction Medicine Source Type: research