The effects of high parity and socioeconomic status on obstetric and neonatal outcome.

We studied the interaction of social status and high parity in 15,102 consecutive births in one inner-city hospital, of which 1874 (12.4%) occurred in mothers who had given birth to seven or more infants (Grand multiparae). Group 1 consisted of 1258 grand multiparae from a socioeconomically stable and homogeneous ultra-orthodox Jewish community in Jerusalem, and group 2, included all other grand multiparae of relatively greater age and lower socioeconomic status. A significantly higher rate of small for gestational age, low birth weight and preterm infants was found in group 2 compared with group 1. The results suggest that grand multiparity is not of itself a risk factor, but reflects the confounding effect of environmental conditions.