Definition of maternal H2S exposure
Women were considered exposed to H2S if they were living and/or workplace in cities along the Atlantic coast of Martinique, which are known to witness sargassum strandings since 2016. Air pollution by H2S were previously identified by a network of ground sensors deployed at these regularly impacted areas along the north central and south Atlantic coast of Martinique. Only women located at a maximum distance of 2000 meters from the closest monitoring site were selected. In this way, all cases that occurred too far from the monitoring sites were excluded, because H2S levels cannot be representative of individual exposure at such distances. All women living and/or workplace in cities outside of the Atlantic coast were assumed to be not exposed to H2S.