We combined marital status and length of union into one variable. We grouped maternal occupation during the pregnancy in a dichotomous variable “working” and “not working” (unemployed, retired, housewife, student, or without activity). Housing type refers to the construction material (brickwork or other materials, e.g., wood, usually found in more precarious housing). We based problems during delivery on maternal report (yes/no), and they refer mostly to hemorrhage and eclampsia.