OBJECTIVE The National Health Service Corps (NHSC) attracts clinicians to Health Professional Shortage Areas (HPSAs) through scholarships and loan repayments. Since 2009, the NHSC workforce, including maternity care clinicians, has substantially expanded. This study evaluates the association between NHSC expansion and prenatal care and birth outcomes. METHODS In this quasi-experimental study, we adopted a generalized difference-in-differences design to compare changes in prenatal care and birth outcomes from 2005 to 2019 using birth certificate data. Counties designated as HPSAs without any NHSC maternity care clinicians throughout the study period were control counties, and those without such clinicians before 2009 but receiving them after 2009 were treated counties. Outcome measures include a count variable of number of prenatal visits and four dichotomous variables: prenatal care initiation in the first trimester, adequacy of prenatal care, preterm birth, and low birth weight. We estimated negative binomial models for number of prenatal visits and linear probability models for the dichotomous outcomes, adjusting for maternal characteristics, non-NHSC clinician density, and state-level policies. Stratified analyses were also conducted on the basis of birthing people's demographics and county-level characteristics. RESULTS Our sample comprised 12,980,111 live births between 2005 and 2019 by individuals residing in 1,254 HPSA counties without any NHSC maternity care clinicians before 2009, including 222 counties that received such clinicians after 2009. Compared with control counties, pregnant people in treated counties experienced significant increases in prenatal visits (211 more prenatal visits relative to baseline of 11,226 visits per 1,000 births, P <.001) and in the likelihood of receiving adequate prenatal care (1.43 percentage point increase relative to baseline of 67.0 percentage points, P <.01). Although the NHSC expansion improved prenatal care use for all racial and ethnic groups, pregnant people residing in urban and high social vulnerability areas benefited most. Improvements in birth outcomes were observed only among certain subgroups such as a 0.91 percentage point reduction in preterm birth (relative to baseline of 12.6 percentage points, P <.001) and a 0.87 percentage point reduction in low birth weight (relative to baseline of 8.2 percentage points, P <.05) among pregnant people living in full-county HPSAs. CONCLUSION The NHSC expansion since 2009 was associated with increases in prenatal care utilization, particularly among vulnerable populations. Although improvements were not observed in birth outcomes overall with NHSC expansion, modest reductions were observed in preterm birth and low birth weight in subsets of the population.

中文翻译：

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国家卫生服务团扩大后的产前保健利用和出生结果。


目的 国家卫生服务团 （NHSC） 通过奖学金和偿还贷款吸引临床医生到卫生专业人员短缺地区 （HPSA）。自 2009 年以来，NHSC 的劳动力，包括产科护理临床医生，已大幅扩大。本研究评估了 NHSC 扩展与产前保健和出生结局之间的关联。方法 在这项准实验研究中，我们采用广义双重差分设计，使用出生证明数据比较 2005 年至 2019 年产前护理和出生结局的变化。在整个研究期间没有任何 NHSC 产科护理临床医生被指定为 HPSA 的县是对照县，而 2009 年之前没有此类临床医生但在 2009 年之后接受治疗的县是接受治疗的县。结局指标包括产前检查次数的计数变量和四个二分类变量：孕早期的产前保健开始、产前保健的充分性、早产和低出生体重。我们估计了产前就诊次数的负二项式模型和二分类结局的线性概率模型，调整了孕产妇特征、非 NHSC 临床医生密度和州级政策。还根据出生人口的人口统计和县级特征进行了分层分析。结果我们的样本包括 2005 年至 2019 年间居住在 1,254 个 HPSA 县的 12,980,111 名活产婴儿，这些县在 2009 年之前没有任何 NHSC 产科护理临床医生，包括 222 年之后接收此类临床医生的 2009 个县。与对照县相比，接受治疗县的孕妇产前检查次数显著增加（相对于每 1,000 名新生儿 11,226 次就诊的基线，产前检查次数增加了 211 次，P <。001） 和接受充分产前护理的可能性 （相对于基线增加 1.43 个百分点 67.0 个百分点，P <.01）。尽管 NHSC 的扩展改善了所有种族和族裔群体的产前保健使用，但居住在城市和高度社会脆弱地区的孕妇受益最大。仅在某些亚组中观察到出生结局的改善，例如早产降低 0.91 个百分点（相对于基线 12.6 个百分点，P <.001）和低出生体重降低 0.87 个百分点（相对于基线 8.2 个百分点，P <.05）生活在全县 HPSA 的孕妇。结论 自 2009 年以来 NHSC 的扩张与产前保健利用率的增加有关，尤其是在弱势群体中。尽管随着 NHSC 的扩大，总体上未观察到出生结局的改善，但在人群子集中观察到早产和低出生体重的适度减少。