“…However, from a methodological point of view, a number of these studies have serious shortcomings (Gray, 1981), mainly because the control for influences of maternal age and parity, the outcome of the previous pregnancy, and the socioeconomic circumstances has been omitted. Analyses presented by Fedrick & Adelstein (1973), Wolfers & Scrimshaw (1975), and Edmonston (1983), are examples of studies which take these variables into account, especially maternal age and parity. Generally, an increased mortality risk in the neonatal and postneonatal period is reported for children with short retrospective intervals, in particular if the interval is less than 1 year.…”