We have designed a combined contrary-sex co-twin manage study to investigate the latest association anywhere between male sex and you will newborn mortality while you are matching to possess gestational many years, and you can unmeasured maternal and you will familial situations, and you will modifying for birthweight and you can birth order given that measured covariates. We applied deterministic study linkage to manufacture a complete-of-people potential cohort out of men-women twin pairs from the hooking up their beginning and you may passing information offered off federal wellness administrative databases in the Brazil, then learnt which cohort to address our very own analysis expectations.