Strengths and limitations
While H2S levels was measured by ground sensors to qualitatively witness gas exposure, the main study limitation is related to the definition of exposed pregnant women, which was based on residence’s location, but not individual portative H2S sensors. Portable gas detectors would represent the best way to compute actual matrix of H2S exposure. Detection of gases emitted by decomposing sargassum seaweed was also limited to H2S, which may not be the unique pollutant emitted by decomposing sargassum seaweed. Increased risk of preeclampsia that we found in exposed pregnant women may be due to volatile and non-volatile compounds which are produced during the process of sargassum seaweed decomposition. It should be wise to compute a proxy indicator, integrating parameters such as multiple gas sensor data, distance between sensors and inhabited zones, as well as pertinent climatic parameters. Air pollutants such as O3, NOx, NO2, SO2 and ambient particulate matters should have been monitored during the study period as they are known risk factors for preeclampsia.