Gaskins Audrey J, Rich-Edwards Janet W, Missmer Stacey A, Rosner Bernard, Chavarro Jorge E
Departments of Nutrition and Epidemiology, Harvard T. H. Chan School of Public Health, and the Channing Division of Network Medicine, Department of Medicine, the Connors Center for Women's Health and Gender Biology, Department of Medicine, and the Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
Obstet Gynecol. 2015 Oct;126(4):850-858. doi: 10.1097/AOG.0000000000001030.
To evaluate whether weight change since age 18 years, current body mass index (BMI), and BMI at age 18 years are associated with fecundity.
Our study included 1,950 women in the Nurses' Health Study 3 (2010-2014), a prospective cohort study, currently attempting pregnancy. Height, current weight, and weight at age 18 years were self-reported on the baseline questionnaire. Every 3-6 months thereafter, women reported the current duration of their pregnancy attempt. Multivariable-accelerated failure time models were used to estimate the time ratios and 95% confidence intervals (CIs).
For every 5-kg increase in body weight from age 18 years, current duration of pregnancy attempt increased by 5% (95% CI 3-7%). Compared with women who maintained weight, the adjusted median current duration was 0.5 months shorter in those who lost weight, 0.3 months longer for those who gained 4-9.9 kg and 10-19.9 kg, and 1.4 months longer for those who gained 20 kg or more (P trend ≤.001). The adjusted time ratio (95% CI) for a 5-kg/m increase in current BMI was 1.08 (1.04-1.12). After multivariable adjustment (including adjustment for current BMI), being underweight at age 18 years (BMI less than 18.5) was associated with a longer current duration of pregnancy attempt compared with normal-weight women (time ratio 1.25, 95% CI 1.07-1.47); however, being overweight or obese at age 18 years was not associated with fecundity.
Gaining weight in adulthood, being overweight or obese in adulthood, and being underweight at age 18 years were associated with a modest reduction in fecundity.
II.
评估自18岁起的体重变化、当前体重指数（BMI）以及18岁时的BMI是否与生育力相关。
我们的研究纳入了护士健康研究3（2010 - 2014年）中的1950名女性，这是一项前瞻性队列研究，她们目前正在尝试怀孕。身高、当前体重以及18岁时的体重通过基线调查问卷自行报告。此后每3 - 6个月，女性报告当前尝试怀孕的时长。使用多变量加速失效时间模型来估计时间比和95%置信区间（CI）。
从18岁起体重每增加5千克，当前尝试怀孕的时长增加5%（95% CI 3 - 7%）。与体重保持不变的女性相比，体重减轻的女性调整后的当前中位数时长缩短了0.5个月，体重增加4 - 9.9千克和10 - 19.9千克的女性时长延长了0.3个月，体重增加20千克或更多的女性时长延长了1.4个月（P趋势≤.001）。当前BMI每增加5千克/平方米，调整后的时间比（95% CI）为1.08（1.04 - 1.12）。经过多变量调整（包括调整当前BMI）后，与体重正常的女性相比，18岁时体重过轻（BMI小于18.5）与当前尝试怀孕的时长较长相关（时间比1.25，95% CI 1.07 - 1.47）；然而，18岁时超重或肥胖与生育力无关。
成年期体重增加、成年期超重或肥胖以及18岁时体重过轻与生育力适度降低相关。
II级。
