Division of Intramural Population Health Research, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
JAMA Pediatr. 2018 Jan 1;172(1):24-31. doi: 10.1001/jamapediatrics.2017.3785.
Despite the increasing prevalence of pregravid obesity, systematic evaluation of the association of maternal obesity with fetal growth trajectories is lacking.
To characterize differences in fetal growth trajectories between obese and nonobese pregnant women, and to identify the timing of any observed differences.
DESIGN, SETTING, AND PARTICIPANTS: The Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies-Singletons study enrolled cohorts of pregnant women at 12 US health care institutions. Obese women (with prepregnancy body mass index > 30) and nonobese women (prepregnancy body mass indexes, 19-29.9) without major chronic diseases were recruited between 8 weeks and 0 days' gestation and 13 weeks and 6 days' gestation. A mixed longitudinal randomization scheme randomized participants into 1 of 4 schedules for 2-dimensional and 3-dimensional ultrasonograms to capture weekly fetal growth data throughout the remainder of their pregnancies.
On each ultrasonogram, fetal humerus length, femur length, biparietal diameter, head circumference, and abdominal circumference were measured. Fetal growth curves were estimated using linear mixed models with cubic splines. Median differences in the fetal measures at each gestational week of the obese and nonobese participants were examined using the likelihood ratio and Wald tests after adjustment for maternal characteristics.
The study enrolled 468 obese and 2334 nonobese women between 8 weeks and 0 days' gestation and 13 weeks and 6 days' gestation. After a priori exclusion criteria, 443 obese and 2320 nonobese women composed the final cohort. Commencing at 21 weeks' gestation, femur length and humerus length were significantly longer for fetuses of obese woman than those of nonobese women. Differences persisted in obese and nonobese groups through 38 weeks' gestation (median femur length, 71.0 vs 70.2 mm; P = .01; median humerus length, 62.2 vs 61.6 mm; P = .03). Averaged across gestation, head circumference was significantly larger in fetuses of obese women than those of nonobese women (P = .02). Fetal abdominal circumference was not greater in the obese cohort than in the nonobese cohort but was significantly larger than in fetuses of normal-weight women (with body mass indexes between 19.0-24.9) commencing at 32 weeks (median, 282.1 vs 280.2 mm; P = .04). Starting from 30 weeks' gestation, estimated fetal weight was significantly larger for the fetuses of obese women (median, 1512 g [95% CI, 1494-1530 g] vs 1492 g [95% CI, 1484-1499 g]) and the difference grew as gestational age increased. Birth weight was higher by almost 100 g in neonates born to obese women than to nonobese women (mean, 3373.2 vs 3279.5 g).
As early as 32 weeks' gestation, fetuses of obese women had higher weights than fetuses of nonobese women. The mechanisms and long-term health implications of these findings are not yet established.
尽管孕前肥胖的患病率不断上升，但缺乏系统评估肥胖母亲与胎儿生长轨迹之间的关联。
描述肥胖和非肥胖孕妇之间胎儿生长轨迹的差异，并确定观察到的差异的时间。
设计、地点和参与者：美国国立儿童健康与人类发展研究所胎儿生长研究-单胎研究在 12 家美国医疗机构招募了孕妇队列。肥胖妇女（孕前体重指数>30）和非肥胖妇女（孕前体重指数 19-29.9）无重大慢性疾病，在 8 周零 0 天至 0 天妊娠和 13 周加 6 天妊娠期间招募。混合纵向随机化方案将参与者随机分配到 4 个 2 维和 3 维超声检查时间表中的 1 个，以在整个妊娠期间捕获每周胎儿生长数据。
在每次超声检查中，测量胎儿肱骨长度、股骨长度、双顶间径、头围和腹围。使用具有三次样条的线性混合模型估计胎儿生长曲线。在调整了母亲特征后，使用似然比和 Wald 检验检查肥胖和非肥胖参与者在每个妊娠周的胎儿测量值中的中位数差异。
该研究在 8 周零 0 天至 0 天妊娠和 13 周加 6 天妊娠期间招募了 468 名肥胖和 2334 名非肥胖妇女。在进行了事先的排除标准后，443 名肥胖和 2320 名非肥胖妇女组成了最终队列。从 21 周妊娠开始，肥胖妇女的胎儿股骨长度和肱骨长度明显长于非肥胖妇女。在肥胖和非肥胖组中，差异一直持续到 38 周妊娠（股骨长度中位数，71.0 与 70.2 毫米；P = .01；肱骨长度中位数，62.2 与 61.6 毫米；P = .03）。在整个妊娠期，肥胖妇女的胎儿头围明显大于非肥胖妇女（P = .02）。肥胖组的胎儿腹围并不大于非肥胖组，但从 32 周开始，明显大于体重正常组（体重指数在 19.0-24.9 之间）（中位数，282.1 与 280.2 毫米；P = .04）。从 30 周妊娠开始，肥胖妇女的胎儿估计体重明显更大（中位数，1512 克[95%CI，1494-1530 克]与 1492 克[95%CI，1484-1499 克]），并且随着胎龄的增加而增加。与非肥胖妇女相比，肥胖妇女分娩的新生儿体重几乎增加了 100 克（平均，3373.2 与 3279.5 克）。
早在 32 周妊娠时，肥胖妇女的胎儿体重就高于非肥胖妇女的胎儿体重。这些发现的机制和长期健康影响尚不清楚。
