Contribution of maternal age and pregnancy checkbox on maternal mortality ratios in the United States, 1978-2012

Increasing age-specific maternal mortality seems to be contributing more heavily than a changing maternal age distribution to recent increases in MMR. In states with the standard pregnancy checkbox, the vast majority of the observed change in MMR over the last decade was estimated to be due to the pregnancy checkbox, with the greatest change in MMR occurring in women ages ≥40 years. The addition of a pregnancy checkbox on state death certificates appears to be increasing case identification but also may be leading to maternal death misclassification, particularly for women ages ≥40 years.