The association of primiparity with intrauterine growth retardation.

The role of parity in the epidemiology of intrauterine growth retardation (IUGR) is not well understood, as some risk factors for IUGR are associated with young age and primiparity, and some are more frequent among older multiparous women. This paper examines the unique role of primiparity in the etiology of IUGR in a series of 25,614 singleton births in the southern part of Israel. The rates of IUGR were 3.5% among primiparae and 1.7% in multiparae. (Risk ratio = 1.99; 95% confidence interval, 1.69-2.35). Maternal age was associated with IUGR only among primiparae but not in multiparae. Of the obstetric factors examined, the following were found to be significantly associated with IUGR: hypertension, prior infertility, oligohydramnios, gross fetal congenital anomalies, and being a female fetus. After simultaneous adjustment for these risk factors by multiple logistic regression analysis, the odds ratio associated with parity was 1.62 (95% confidence interval, 1.30-2.01), suggesting that primiparity constitutes an independent risk factor for IUGR.