Whether women who delay childbearing are at increased risk for adverse outcomes of pregnancy is of concern because of the growing proportion of first births to older women. We assessed the effect of advancing maternal age on the outcome of pregnancy in first births in a hospital-based cohort study of 3917 private patients who were 20 years of age or older with a singleton gestation. There was a slight elevation in the risk of having a low-birth-weight infant among women who were 35 years of age or older (adjusted odds ratio, 1.3; 95 percent confidence interval, 0.9 to 1.9) as compared with the risk among women 20 to 29 years of age. However, there was no evidence that women between 30 and 34 or those 35 and older had an increased risk of having a preterm delivery or of having an infant who was small for gestational age, had a low Apgar score, or died in the perinatal period. In contrast, even after controlling for sociodemographic and medical risk factors, we found that women who were 35 or older were significantly more likely to have specific antepartum and intrapartum complications and those who were 30 or older were significantly more likely to have both cesarean sections and infants who were admitted to the newborn intensive care unit. This study suggests that although older primiparous women have higher rates of complications of pregnancy and delivery, their risk of a poor neonatal outcome is not appreciably increased.

https://www.nejm.org/doi/pdf/10.1056/NEJM199003083221004

Delayed childbearing and the outcome of pregnancy.

Pregnancy outcome at age 40 and older

'Informed and uninformed decision making'--women's reasoning, experiences and perceptions with regard to advanced maternal age and delayed childbearing: a meta-synthesis.

Very advanced maternal age: Pregnancy after age 45

Objective. —To study the consequences of delayed first childbearing in a large, population-based US sample, with separate analysis of women aged 40 years or more and adjustment for socioeconomic factors, smoking, medical and reproductive conditions, and route of delivery. Design and Setting. —Retrospective survey of Washington State birth certificates from 1984 through 1988. Subjects. —First liveborn singleton infants of women aged at least 20 years. Of eligible white infants, all those born to women aged 35 to 39 years (n=4019) and 40 years or more (n=410) and a maternal age-stratified random sample of white infants of younger women were studied. All eligible black infants were studied. Outcome Measures. —Low ( Results. —Adjusted odds ratios for delivering a low-birth-weight white infant increased progressively with each 5-year maternal age group, reaching 2.3 (95% confidence interval, 1.6 to 3.4) for women aged 40 years or more compared with those aged 20 to 24 years. The maternal age effects for very low birth weight and preterm delivery were similar; for each, the odds ratio was 1.8 for the oldest group. No significant maternal age effect was found among births of black infants, but only 127 births to women aged 35 years or more were studied. Conclusion. —Increasing maternal age at first childbirth is an independent risk factor for low birth weight and preterm delivery of white infants in the United States. ( JAMA . 1993;270:2574-2577)

Israel Sl

Papers

Relation of the mother's age to obstetric performance.