National Vital Statistics System reports show that maternal mortality rates in the United States have nearly doubled, from 17.4 in 2018 to 32.9 per 100,000 live births in 2021. However, these high and rising rates could reflect issues unrelated to obstetrical factors, such as changes in maternal medical conditions or maternal mortality surveillance (eg, due to introduction of the pregnancy checkbox). This study aimed to assess if the high and rising rates of maternal mortality in the United States reflect changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance. The study was based on all deaths in the United States from 1999 to 2021. Maternal deaths were identified using the following 2 approaches: (1) per National Vital Statistics System methodology, as deaths in pregnancy or in the postpartum period, including deaths identified solely because of a positive pregnancy checkbox, and (2) under an alternative formulation, as deaths in pregnancy or in the postpartum period, with at least 1 mention of pregnancy among the multiple causes of death on the death certificate. The frequencies of major cause-of-death categories among deaths of female patients aged 15 to 44 years, maternal deaths, deaths due to obstetrical causes (ie, direct obstetrical deaths), and deaths due to maternal medical conditions aggravated by pregnancy or its management (ie, indirect obstetrical deaths) were quantified. Maternal deaths, per National Vital Statistics System methodology, increased by 144% (95% confidence interval, 130–159) from 9.65 in 1999–2002 (n=1550) to 23.6 per 100,000 live births in 2018–2021 (n=3489), with increases occurring among all race and ethnicity groups. Direct obstetrical deaths increased from 8.41 in 1999–2002 to 14.1 per 100,000 live births in 2018–2021, whereas indirect obstetrical deaths increased from 1.24 to 9.41 per 100,000 live births: 38% of direct obstetrical deaths and 87% of indirect obstetrical deaths in 2018–2021 were identified because of a positive pregnancy checkbox. The pregnancy checkbox was associated with increases in less specific and incidental causes of death. For example, maternal deaths with malignant neoplasms listed as a multiple cause of death increased 46-fold from 0.03 in 1999–2002 to 1.42 per 100,000 live births in 2018–2021. Under the alternative formulation, the maternal mortality rate was 10.2 in 1999–2002 and 10.4 per 100,000 live births in 2018–2021; deaths from direct obstetrical causes decreased from 7.05 to 5.82 per 100,000 live births. Deaths due to preeclampsia, eclampsia, postpartum hemorrhage, puerperal sepsis, venous complications, and embolism decreased, whereas deaths due to adherent placenta, renal and unspecified causes, cardiomyopathy, and preexisting hypertension increased. Maternal mortality increased among non-Hispanic White women and decreased among non-Hispanic Black and Hispanic women. However, rates were disproportionately higher among non-Hispanic Black women, with large disparities evident in several causes of death (eg, cardiomyopathy). The high and rising rates of maternal mortality in the United States are a consequence of changes in maternal mortality surveillance, with reliance on the pregnancy checkbox leading to an increase in misclassified maternal deaths. Identifying maternal deaths by requiring mention of pregnancy among the multiple causes of death shows lower, stable maternal mortality rates and declines in maternal deaths from direct obstetrical causes.

中文翻译：

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美国孕产妇死亡率：死亡率高且不断上升是由于产科因素、孕产妇医疗条件或孕产妇死亡率监测的变化造成的吗？


国家生命统计系统报告显示，美国的孕产妇死亡率几乎翻了一番，从 2018 年的每 10 万活产儿 17.4 例上升到 2021 年的每 10 万活产儿 32.9 例。然而，这些高且不断上升的死亡率可能反映了与产科因素无关的问题，例如产科因素的变化。孕产妇医疗状况或孕产妇死亡率监测（例如，由于引入怀孕复选框）。本研究旨在评估美国孕产妇死亡率高且不断上升是否反映了产科因素、孕产妇医疗状况或孕产妇死亡率监测的变化。该研究以 1999 年至 2021 年美国的所有死亡为基础。使用以下 2 种方法确定孕产妇死亡：(1) 根据国家生命统计系统方法，妊娠期或产后死亡，包括仅确定的死亡因为怀孕复选框呈阳性，以及 (2) 根据替代表述，作为怀孕期间或产后死亡，死亡证明上的多种死亡原因中至少有 1 处提及怀孕。 15至44岁女性患者死亡、孕产妇死亡、产科原因死亡（即直接产科死亡）以及因妊娠或其处理而加重的孕产妇医疗状况导致的死亡中主要死因类别的频率（即间接产科死亡）进行了量化。根据国家人口动态统计系统方法，孕产妇死亡人数增加了 144%（95% 置信区间，130-159），从 1999-2002 年的每 100,000 例活产 9.65 例 (n=1550) 增加到 2018-2021 年的每 100,000 例活产 23.6 例 (n=3489) ，所有种族和族裔群体中都有增加。直接产科死亡人数从 1999-2002 年的 8.41 人增加到 14 人。2018-2021 年，每 10 万活产中有 1 例，而间接产科死亡从每 10 万活产 1.24 例增加到 9.41 例：2018-2021 年，38% 的直接产科死亡和 87% 的间接产科死亡是由于妊娠复选框呈阳性而确定的。怀孕复选框与不太具体和偶然的死亡原因的增加有关。例如，被列为多种死因的恶性肿瘤孕产妇死亡人数增加了 46 倍，从 1999 年至 2002 年的每 10 万活产 0.03 例增加到 2018 年至 2021 年每 10 万活产 1.42 例。根据替代方案，1999-2002 年孕产妇死亡率为每 10 万活产 10.2 例，2018-2021 年为每 10 万活产 10.4 例；直接产科原因造成的死亡从每 10 万活产 7.05 人下降到 5.82 人。先兆子痫、子痫、产后出血、产后败血症、静脉并发症和栓塞导致的死亡人数减少，而胎盘粘连、肾脏和不明原因、心肌病和既往高血压导致的死亡人数增加。非西班牙裔白人妇女的孕产妇死亡率上升，非西班牙裔黑人和西班牙裔妇女的孕产妇死亡率下降。然而，非西班牙裔黑人女性的死亡率要高得多，几种死因（例如心肌病）之间存在明显的巨大差异。美国孕产妇死亡率居高不下且不断上升，是孕产妇死亡率监测变化的结果，对怀孕复选框的依赖导致错误分类的孕产妇死亡人数增加。通过要求在多种死亡原因中提及怀孕来确定孕产妇死亡，表明孕产妇死亡率较低且稳定，并且直接产科原因导致的孕产妇死亡人数有所下降。