Medical and obstetric complications among pregnant women aged 45 and older

Abstract

Objective: The number of women aged 45 and older who become pregnant is increasing. The objective of this study was to estimate the risk of medical and obstetric complications among women aged 45 and older.

Methods: The Nationwide Inpatient Sample was used to identify pregnant woman during admission for delivery. Deliveries were identified using International Classification of Diseases, Ninth Revision (ICD-9-CM) codes. Using ICD-9-CM codes, pre-existing medical conditions and medical and obstetric complications were identified in women at the time of delivery and were compared for women aged 45 years and older to women under age 35. Outcomes among women aged 35-44 were also compared to women under age 35 to determine if women in this group demonstrated intermediate risk between the older and younger groups. Logistic regression analyses were used to calculate odds ratios with 95% confidence intervals for pre-existing medical conditions and medical and obstetric complications for both older groups relative to women under 35. Multivariable logistic regression analyses were also developed for outcomes at delivery among older women, while controlling for pre-existing medical conditions, multiple gestation, and insurance status, to determine the effect of age on the studied outcomes.

Results: Women aged 45 and older had higher adjusted odds for death, transfusion, myocardial infarction/ischemia, cardiac arrest, acute heart failure, pulmonary embolism, deep vein thrombosis, acute renal failure, cesarean delivery, gestational diabetes, fetal demise, fetal chromosomal anomaly, and placenta previa compared to women under 35.

Conclusion: Pregnant women aged 45 and older experience significantly more medical and obstetric complications and are more likely to die at the time of a delivery than women under age 35, though the absolute risks are low and these events are rare. Further research is needed to determine what associated factors among pregnant women aged 45 and older may contribute to these findings.

Figure 1. Change in the total number of births and in the birth rate among women aged 45 and older.

A. Trends in the number of births to women aged 45–49 per 1000 total US deliveries between 1990 and 2010 and to women aged 50 to 54 per 1000 total US deliveries between 1997 and 2010 (data from Centers for Disease Control and Prevention. National Center for Health Statistics. VitalStats. http://www.cdc.gov/nchs/vitalstats.htm. Date of access 11/24/12). There was a significant linear increase in the total number of births to women aged 45–49 (p<0.0001, R² = 0.997) and to women age 50–54 (p<0.0001, R² = 0.984) per 1000 total US deliveries. B. Trends in the birth rate among women aged 45–49 per all women aged 45–49. The birth rate among women aged 45 to 49 per 1000 women in that age group remained unchanged from 1980 to 1991 at 0.2 per 1000 women in that age group, per year, but increased to 0.7 per 1000 women aged 45 to 49 by 2010.