Hamad Rita, Collin Daniel F, Baer Rebecca J, Jelliffe-Pawlowski Laura L
Department of Family & Community Medicine, University of California, San Francisco.
Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco.
JAMA Pediatr. 2019 Sep 1;173(9):845-852. doi: 10.1001/jamapediatrics.2019.1706.
The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) serves more than one-quarter of pregnant and postpartum women. In October 2009, the WIC food package underwent revisions to improve nutritional content. No studies have investigated the downstream effects of this revision on maternal and infant health.
To investigate whether the revised WIC food package improved perinatal and birth outcomes among recipients.
DESIGN, SETTING, AND PARTICIPANTS: We conducted a quasi-experimental difference-in-differences analysis, comparing WIC recipients (the treatment group) before and after the package revisions while accounting for temporal trends among nonrecipients (the control group). Multivariable linear regressions were adjusted for sociodemographic covariates. This study was conducted using linked birth certificate and hospital discharge data from California from January 2007 to December 2012. Analysis began July 2018.
Whether pregnant women received the revised WIC package, which included more whole grains, fruit, vegetables, and low-fat milk.
Measures of maternal and infant health, including maternal preeclampsia, gestational diabetes, and gestational weight gain as well as infant gestational age, birth weight, and hospitalizations.
The sample included 2 897 537 infants born to 2 441 658 mothers. WIC recipients were more likely to be Hispanic, less educated, of greater parity, and younger than nonrecipients. The revised WIC food package was associated with reductions in maternal preeclampsia (-0.6% points; 95% CI, -0.8 to -0.4) and more than recommended gestational weight gain (-3.2% points; 95% CI, -3.6 to -2.7), increased likelihood of as recommended (2.3% points; 95% CI, 1.8 to 2.8) and less than recommended (0.9% points; 95% CI, 0.5 to 1.2) gestational weight gain, and longer gestational age (0.2 weeks; 95% CI, 0.001 to 0.034). Among infants, an increased likelihood of birth weight that was appropriate for gestational age was observed (0.9% points; 95% CI, 0.5 to 1.3). Although birth weight itself was reduced (-0.009 SDs; 95% CI, -0.016 to -0.001), this was accompanied by reductions in small for gestational age (-0.4% points; 95% CI, -0.7 to -0.1), large for gestational age (-0.5% points; 95% CI, -0.8 to -0.2), and low-birth-weight infants (-0.2% points; 95% CI, -0.4 to -0.004), suggesting that the revised food package improved distributions of birth weight.
The revised WIC food package, intended to improve women's nutrition during pregnancy, was associated with beneficial impacts on maternal and child health. This suggests that WIC policy may be an important lever to reduce health disparities among high-risk women and children at a critical juncture in the life course.
妇女、婴儿和儿童特殊补充营养计划（WIC）为超过四分之一的孕妇和产后妇女提供服务。2009年10月，WIC食品套餐进行了修订，以提高营养成分。尚无研究调查此次修订对母婴健康的下游影响。
调查修订后的WIC食品套餐是否改善了受助者的围产期和出生结局。
设计、设置和参与者：我们进行了一项准实验性的差异分析，比较了套餐修订前后的WIC受助者（治疗组），同时考虑了非受助者（对照组）的时间趋势。多变量线性回归针对社会人口学协变量进行了调整。本研究使用了2007年1月至2012年12月加利福尼亚州的链接出生证明和医院出院数据。分析于2018年7月开始。
孕妇是否收到修订后的WIC套餐，其中包括更多的全谷物、水果、蔬菜和低脂牛奶。
母婴健康指标，包括孕妇先兆子痫、妊娠期糖尿病和妊娠期体重增加，以及婴儿的胎龄、出生体重和住院情况。
样本包括2441658名母亲所生的2897537名婴儿。WIC受助者比非受助者更有可能是西班牙裔、受教育程度较低、多胎且年龄较小。修订后的WIC食品套餐与孕妇先兆子痫发生率降低（-0.6个百分点；95%置信区间，-0.8至-0.4）、妊娠期体重增加超过推荐值的情况减少（-3.2个百分点；95%置信区间，-3.6至-2.7）、妊娠期体重增加达到推荐值的可能性增加（2.3个百分点；95%置信区间，1.8至2.8）以及低于推荐值的可能性增加（0.9个百分点；95%置信区间，0.5至1.2）、胎龄延长（0.2周；95%置信区间，0.001至0.034）有关。在婴儿中，观察到出生体重适合胎龄的可能性增加（0.9个百分点；95%置信区间，0.5至1.3）。尽管出生体重本身有所降低（-0.009标准差；95%置信区间，-0.016至-0.001），但同时小于胎龄儿（-0.4个百分点；95%置信区间，-0.7至-0.1）、大于胎龄儿（-0.5个百分点；95%置信区间，-0.8至-0.2）和低出生体重儿（-0.2个百分点；95%置信区间，-0.4至-0.004）的发生率也有所降低，这表明修订后的食品套餐改善了出生体重的分布。
旨在改善孕期妇女营养的修订后的WIC食品套餐，对母婴健康产生了有益影响。这表明WIC政策可能是在生命历程的关键阶段减少高危妇女和儿童健康差距的重要杠杆。
