Original Research

The Perinatal Effects of Delayed Childbearing

Joseph, K S. MD, PhD¹; Allen, Alexander C. MD¹; Dodds, Linda PhD¹; Turner, Linda Ann PhD³; Scott, Heather MD²; Liston, Robert MB⁴

Author Information

From the 1Perinatal Epidemiology Research Unit, Departments of Obstetrics and Gynaecology and Pediatrics, and the 2Division of Maternal Fetal Medicine, Department of Obstetrics and Gynaecology, Dalhousie University, and the IWK Health Centre, Halifax, Nova Scotia, Canada; 3the Centre for Studies in Family Medicine, the University of Western Ontario, London, Ontario, Canada; and 4the Department of Obstetrics and Gynaecology, Children's & Women's Health Centre of British Columbia and the University of British Columbia, Vancouver, British Columbia, Canada.

Drs. Joseph and Dodds are supported by Clinical Scholar awards from the Dalhousie University Faculty of Medicine. Dr. Joseph is a Peter Lougheed New Investigator and Dr. Dodds is a New Investigator of the Canadian Institutes of Health Research. This study was funded by a grant from the Canadian Institutes of Health Research (MOP-43992).

The authors thank the Small Area and Administrative Data Division of Statistics Canada, especially Pat Grainger, Eric Olson, Jeffrey Smith, Linda Standish, Bill Steele, Tom Swoger and Kathleen Trudeau, for database linkage and analysis. They also thank the Reproductive Care Program of Nova Scotia for access to the data.

Address reprint requests to: Dr. K. S. Joseph, Division of Neonatal Pediatrics, IWK Health Centre, 5980 University Avenue, Halifax, Nova Scotia, Canada B3K 6R8; e-mail: [email protected].

Received November 17, 2004. Received in revised form February 25, 2005. Accepted March 3, 2005.

Obstetrics & Gynecology 105(6):p 1410-1418, June 2005. | DOI: 10.1097/01.AOG.0000163256.83313.36

OBJECTIVE:

To determine if the rates of pregnancy complications, preterm birth, small for gestational age, perinatal mortality, and serious neonatal morbidity are higher among mothers aged 35–39 years or 40 years or older, compared with mothers 20–24 years.

METHODS:

We performed a population-based study of all women in Nova Scotia, Canada, who delivered a singleton fetus between 1988 and 2002 (N = 157,445). Family income of women who delivered between 1988 and 1995 was obtained through a confidential linkage with tax records (n = 76,300). The primary outcome was perinatal death (excluding congenital anomalies) or serious neonatal morbidity. Analysis was based on logistic models.

RESULTS:

Older women were more likely to be married, affluent, weigh 70 kg or more, attend prenatal classes, and have a bad obstetric history but less likely to be nulliparous and to smoke. They were more likely to have hypertension, diabetes mellitus, placental abruption, or placenta previa. Preterm birth and small-for-gestational age rates were also higher; compared with women aged 20–24 years, adjusted rate ratios for preterm birth among women aged 35–39 years and 40 years or older were 1.61 (95% confidence interval [CI] 1.42–1.82; P < .001) and 1.80 (95% CI 1.37–2.36; P < .001), respectively. Adjusted rate ratios for perinatal mortality/morbidity were 1.46 (95% CI 1.11–1.92; P = .007) among women 35–39 years and 1.95 (95% CI 1.13–3.35; P = .02) among women 40 years or older. Perinatal mortality rates were low at all ages, especially in recent years.

CONCLUSION:

Older maternal age is associated with relatively higher risks of perinatal mortality/morbidity, although the absolute rate of such outcomes is low.

LEVEL OF EVIDENCE:

II-2

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