Maternal obesity, weight gain and the black-white disparity in stillbirth

描述(申请人提供)：死产是一个未被充分研究的问题，在世界范围内造成了巨大的疾病负担。据报道，2005年美国有近2.6万例死产，几乎相当于当年婴儿死亡人数。美国黑人在怀孕20周时每1000名新生儿中就有11.13名胎儿死亡，这与美国白人4.79的胎儿死亡率形成了鲜明对比。目前，白人和黑人女性之间死产发生率长期存在差异的原因在很大程度上仍不清楚。然而，一种可能性可能与怀孕前和怀孕期间的母亲体重有关。我们建议检验这一假设，即孕妇在怀孕前和怀孕期间的极端体重导致死产的黑白差异。我们的具体目标是(1)确定孕妇孕前体重指数(BMI)和孕期体重增加对产前死产风险的独立和联合贡献。(2)探讨孕前BMI和孕期体重增加对产前死产黑白差异的影响。(3)探讨孕前BMI与孕期体重增加(模式和总增长)以及由病理生理因素或原因确定的产前死产亚型之间的独立和联合关系。为了实现这些具体目标，我们将在宾夕法尼亚州匹兹堡的玛吉妇女医院进行一项病例队列研究，研究对象为172,290名单身产妇(1989年至2009年)，其中包括估计的879例产前死产。死产病例将通过州胎儿死亡记录和医院分娩数据库进行识别。由7名母胎医学专家组成的陪审团将审查病历，确认产前死产，并使用现代分类系统确定其可能的原因(S)。我们将通过围产期病理学家对所有死产的胎盘组织学检查来确定死产的病理生理因素和途径。对于研究中的所有妊娠，我们将用通过医疗记录审查确定的整个妊娠期间测量的体重数据来补充分娩数据库中的现有信息。怀孕期间的体重增加将通过两种方式进行检查：妊娠体重增加的模式和高于、在和低于修订的2009年国际移民组织体重增加建议的总体重增加(这包括对怀孕期间体重减轻或没有增加体重的具体检查)。我们在定义孕期体重增加充分性、研究体重增加模式和确定死产原因方面的创新方法将避免错误分类，并为揭示孕前体重和体重增加与胎儿死亡率之间的联系提供线索。这项新颖的、具有成本效益的研究建立在现有文献的基础上，并通过使用创新的方法来充分探索孕前体重和体重增加-两个潜在的可修改因素-对胎儿死亡中黑人和白人差异的贡献。

DESCRIPTION (provided by applicant): Stillbirth is an understudied problem that imposes a tremendous burden of disease worldwide. In the United States nearly 26,000 stillbirths were reported in 2005, almost equaling the number of infant deaths that year. U.S. blacks experienced 11.13 fetal deaths at e20 weeks gestation per 1000 births, which is in stark contrast to the fetal death rate of 4.79 among U.S. whites. The reasons for the enduring disparity in stillbirth incidence rates today between white and black woman remain largely unknown. One possibility, however, may be related to maternal weight before and during pregnancy. We propose to test the hypothesis that extremes of maternal weight before and during pregnancy contribute to the black-white disparity in stillbirth. Our specific aims are (1) To determine the independent and joint contribution of maternal prepregnancy body mass index (BMI) and weight gain during pregnancy to the risk of antepartum stillbirth. (2) To evaluate the contribution of maternal pregravid BMI and weight gain during pregnancy to the black-white disparity in antepartum stillbirth. (3) To evaluate the independent and joint association between maternal pregravid BMI and weight gain during pregnancy (pattern and total gain) and subtypes of antepartum stillbirth defined by pathophysiologic contributors or causes. To achieve these specific aims, we will conduct a case-cohort study using a population of 172,290 singleton deliveries at Magee- Womens Hospital in Pittsburgh, PA (1989 to 2009), which includes an estimated 879 antepartum stillbirths. Cases of stillbirth will be identified through state fetal death records and a hospital delivery database. Medical record review by a jury of 7 maternal-fetal medicine specialists will confirm antepartum stillbirth and define its likely cause(s) using a contemporary classification system. We will identify pathophysiologic contributors and pathways to stillbirth with a perinatal pathologist's examination of placental histology from all stillbirths. For all pregnancies in the study, we will supplement existing information in the delivery database with data on measured weights throughout gestation ascertained through medical record review. Weight gain during pregnancy will be examined two ways: pattern of gestational weight gain and total weight gain above, within, and below the revised 2009 IOM weight gain recommendations (this includes a specific examination of weight loss or no weight gain during pregnancy). Our innovative methods for defining gestational weight gain adequacy, studying pattern of weight gain, and assigning causes of stillbirth will avoid misclassification and provides clues into mechanisms linking prepregnancy weight and weight gain to fetal mortality. This novel, cost-efficient study builds upon and extends existing literature by using innovative methods to fully explore the contribution of pregravid weight and weight gain-two potentially modifiable factors-to black-white disparities in fetal death.