Maternal age and risk for adverse outcomes

The objective of this study was to characterize the risk for severe maternal morbidity and other pregnancy complications by maternal age during delivery hospitalizations.

This retrospective cohort analysis used the Perspective database to characterize the risk for adverse maternal outcomes from 2006 to 2015 based on maternal age. Women were divided into 7 categories based on maternal age: 15-17, 18-24, 25-29, 30-34, 35-39, 40-44, and 45-54 years of age. The primary outcome of this study was severe maternal morbidity as defined by the Centers for Disease Control and Prevention. Secondary outcomes included (1) overall comorbid risk; (2) risk for pregnancy complications such as postpartum hemorrhage, gestational diabetes, preeclampsia, and cesarean delivery; and (3) risk for individual severe morbidity diagnoses such as stroke, embolism, eclampsia, and hysterectomy. Adjusted models were fitted to assess factors associated with severe morbidity with adjusted risk ratios (aRRs) and 95% confidence intervals (CI) as measures of effect. Population weights were applied to create national estimates.

Of 36,944,292 deliveries included, 2.5% occurred among women aged 15-17 years (n = 921,236), 29.1% to women aged 18-24 years (n = 10,732,715), 28.6% to women aged 25-29 years (n = 10,564,850), 24.9% to women aged 30-34 years (n = 9,213,227), 12.1% to women aged 35-39 years (n = 4,479,236), 2.6% to women aged 40-44 years (n = 974,289), and 0.2% to women aged 45-54 years (n = 58,739). In unadjusted analyses, severe morbidity was more than 3 times higher (risk ratio [RR], 3.33, 95% confidence interval [CI], 3.03-3.66) for women 45-54 years compared with women 25-29 years. Women aged 40-44, 35-39, and 15-17 years were also at increased risk (RR, 1.83, 95% CI, 1.77-1.89; RR, 1.36, 95% CI, 1.33-1.39; RR, 1.39, 95% CI, 1.34-1.45, respectively). In the adjusted model, the 45-54 year old group was associated with the highest relative risk (aRR, 3.46, 95% CI, 3.15-3.80) followed by the 40-44 year old group (aRR 1.90, 95% CI, 1.84-1.97), the 35-39 year old group (aRR, 1.43, 95% CI, 1.40-1.47), and the 15-17 year old group (aRR, 1.20, 95% CI, 1.15-1.24). Cesarean delivery, preeclampsia, postpartum hemorrhage, and gestational diabetes were most common among women aged 45-54 years, as were thrombosis and hysterectomy.

While differential risk was noted across maternal age categories, women aged 45 years old and older were at highest risk for a broad range of adverse outcomes during delivery hospitalizations.