Influence of age, birth order and reproductive compensation on stillbirth ratios

Abstract

This analysis was planned to produce an estimate of the effects of maternal ageing on the risk of stillbirth which would not be confounded by other biological and socio-economic factors. The basic comparison is between late fetal death ratios in second and third births for all women who experienced third single births in California in 1968. The analysis leads to the conclusion that women who experience late fetal deaths initiate more subsequent pregnancies and after shorter intervals than do women who have live births. A sharply lower risk of late fetal death for third birth than for second was found to mask age effects. It is suggested that this reduction in risk reflects the effects of successful diagnosis and treatment of conditions which produce high rates of pregnancy loss.