Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA, USA.
Shenzhen Birth Cohort Study Center, Nanshan Maternity and Child Healthcare Hospital of Shenzhen, Shenzhen, China.
Lancet Diabetes Endocrinol. 2019 Sep;7(9):707-714. doi: 10.1016/S2213-8587(19)30193-7. Epub 2019 Aug 5.
The relation between maternal pre-pregnancy obesity and preterm birth is controversial and inconclusive. We aimed to clarify the association between pre-pregnancy obesity and preterm birth by maternal age and race or ethnicity in a large, multiracial, multiethnic, and diverse population in the USA.
We did a population-based cohort study using nationwide birth certificate data from the US National Vital Statistics System for 2016 and 2017. We included all mothers who had a live singleton birth and who did not have pre-existing hypertension or diabetes. Pre-pregnancy obesity was defined as a pre-pregnancy BMI of at least 30 kg/m. Preterm birth was defined as gestational age of less than 37 weeks. We used logistic regression models adjusted for maternal age, race or ethnicity, parity, education levels, smoking during pregnancy, previous history of preterm birth, marital status, infant sex, and timing of initiation of prenatal care to estimate the odds ratio (OR) of preterm birth.
We included 7 141 630 singleton livebirths in our analysis, 527 637 (7·4%) of which were preterm births. 127 611 (7·5%) Hispanic mothers, 244 578 (6·6%) non-Hispanic white mothers, and 102 509 (10·4%) non-Hispanic black mothers had preterm births. In the overall population, maternal pre-pregnancy obesity was significantly associated with an increased risk of preterm birth compared with maternal pre-pregnancy healthy weight (ie, BMI of 18·5-24·9 kg/m; adjusted OR 1·18 [95% CI 1·18-1·19]). In non-Hispanic white women, maternal obesity was inversely associated with preterm birth among those younger than 20 years (adjusted OR 0·92 [95% CI 0·88-0·97]), but positively associated with preterm birth among those aged 20 years or older (1·04 [1·01-1·06], 1·20 [1·18-1·23], 1·34 [1·31-1·37], 1·40 [1·36-1·43], and 1·39 [1·31-1·46] among those aged 20-24 years, 25-29 years, 30-34 years, 35-39 years, and ≥40 years, respectively). In Hispanic women, maternal obesity was not associated with preterm birth among those younger than 20 years (0·98 [0·93-1·04]), but positively associated with preterm birth among those aged 20 years or older (1·06 [1·03-1·09], 1·21 [1·17-1·24], 1·32 [1·28-1·36], 1·38 [1·33-1·43], and 1·30 [1·22-1·40] among those aged 20-24 years, 25-29 years, 30-34 years, 35-39 years, and ≥40 years, respectively). In non-Hispanic black women, maternal obesity was inversely associated with preterm birth among those younger than 30 years (0·76 [0·71-0·81] in those <20 years, 0·83 [0·80-0·86] in those aged 20-24 years, and 0·98 [0·95-1·01] among those aged 25-29 years), but positively associated with preterm birth among those aged 30 years or older (1·15 [1·11-1·19], 1·26 [1·20-1·32], and 1·29 [1·18-1·42] among those aged 30-34 years, 35-39 years, and ≥40 years, respectively).
Maternal pre-pregnancy obesity is significantly associated with the risk of preterm birth in the general population, but the risk differs according to maternal age and race or ethnicity. Future investigation is warranted to understand the underlying mechanisms.
US National Institutes of Health.
母亲孕前肥胖与早产之间的关系存在争议，尚无定论。我们旨在通过在美国一个多民族、多种族和多样化的大型人群中按母亲年龄和种族或族裔来阐明孕前肥胖与早产之间的关联。
我们使用来自美国国家生命统计系统的 2016 年和 2017 年全国出生证明数据进行了一项基于人群的队列研究。我们纳入了所有活产单胎的母亲，且这些母亲无先存高血压或糖尿病。孕前肥胖定义为孕前 BMI 至少为 30kg/m。早产定义为妊娠周数不足 37 周。我们使用了经过调整母亲年龄、种族或族裔、产次、教育水平、孕期吸烟、早产史、婚姻状况、婴儿性别和产前保健开始时间的 logistic 回归模型，来估计早产的比值比（OR）。
我们在分析中纳入了 7141630 例活产单胎，其中 527637 例（7.4%）为早产。127611 例（7.5%）西班牙裔母亲、244578 例（6.6%）非西班牙裔白种人母亲和 102509 例（10.4%）非西班牙裔黑种人母亲发生了早产。在总体人群中，与孕前健康体重（即 BMI 为 18.5-24.9kg/m）的母亲相比，母亲孕前肥胖与早产的风险显著增加（调整 OR 1.18 [95%CI 1.18-1.19]）。在非西班牙裔白人女性中，对于年龄小于 20 岁的女性，肥胖与早产呈负相关（调整 OR 0.92 [95%CI 0.88-0.97]），而对于年龄 20 岁或以上的女性，肥胖与早产呈正相关（1.04 [1.01-1.06]、1.20 [1.18-1.23]、1.34 [1.31-1.37]、1.40 [1.36-1.43]和 1.39 [1.31-1.46]，分别为年龄在 20-24 岁、25-29 岁、30-34 岁、35-39 岁和≥40 岁的女性）。在西班牙裔女性中，对于年龄小于 20 岁的女性，肥胖与早产无相关性（0.98 [0.93-1.04]），而对于年龄 20 岁或以上的女性，肥胖与早产呈正相关（1.06 [1.03-1.09]、1.21 [1.17-1.24]、1.32 [1.28-1.36]、1.38 [1.33-1.43]和 1.30 [1.22-1.40]，分别为年龄在 20-24 岁、25-29 岁、30-34 岁、35-39 岁和≥40 岁的女性）。在非西班牙裔黑人女性中，肥胖与年龄小于 30 岁的女性早产呈负相关（年龄<20 岁的女性为 0.76 [0.71-0.81]，年龄在 20-24 岁的女性为 0.83 [0.80-0.86]，年龄在 25-29 岁的女性为 0.98 [0.95-1.01]），而与年龄 30 岁或以上的女性早产呈正相关（1.15 [1.11-1.19]、1.26 [1.20-1.32]和 1.29 [1.18-1.42]，分别为年龄在 30-34 岁、35-39 岁和≥40 岁的女性）。
母亲孕前肥胖与早产的风险在一般人群中显著相关，但风险因母亲年龄和种族或族裔而异。需要进一步研究以了解潜在机制。
美国国立卫生研究院。
