Previous extrauterine pregnancies and neonatal outcomes in primiparous women--an analysis of the German Perinatal Survey.

Aim: The aim of this study was to compare neonatal outcomes in primiparous women with and without previous extrauterine pregnancies. Material and Methods: We analysed data from 207 171 singleton pregnancies in primiparous women from the German Perinatal Survey of 1998-2000. To minimise confounding factors, we only included women without previous miscarriages or terminations of pregnancy and performed comparisons separately for 3 maternal age groups as well as for all cases together. Results: Women with and without previous extrauterine pregnancies were of comparable height and weight but women with previous extrauterine pregnancies were on average older (29.2 vs. 26.6 years). The preterm birth rate was higher in women with previous extrauterine pregnancies (9.4 % vs. 6.8 %, odds ratio 1.42 [95 % confidence interval 1.18-1.69], p < 0.001; analysing all cases together) as was the rate of neonates with a low birth weight <= 2 499 g (7.9 % vs. 5.7 %, odds ratio 1.43 [95 % confidence interval 1.17-1.72], p > 0.001; analysing all cases together). The proportions of neonates classified as small, appropriate, or large for gestational age were rather similar in women with and without previous extrauterine pregnancies; likewise Apgar scores differed only slightly, although for some comparisons statistical significance was reached in spite of the small magnitude of differences. Conclusions: Previous extrauterine pregnancies are associated with higher rates of preterm birth and infants of low birth weight in subsequent pregnancies.