Harvard Pilgrim Health Care Institute, Boston, Massachusetts;
Harvard Medical School, Harvard University, Boston, Massachusetts; and.
Pediatrics. 2019 Feb;143(2). doi: 10.1542/peds.2018-2463. Epub 2019 Jan 15.
Timely contraceptive initiation is increasingly common, yet population trends by method and among subgroups with increased risk of unintended pregnancy are not well described. The impact of timing and type of contraceptive initiation on risk of unwanted pregnancy is unknown.
We used nationally representative cross-sectional data from 4 cycles of the National Survey of Family Growth, 2002-2015. We calculated outcomes from self-reported dates of sexual debut, contraceptive initiation, and unwanted pregnancy. We compared trends in timely contraceptive initiation (within 1 month of sexual debut) by method and by race and/or ethnicity and income. Using multivariable regression, we identified predictors of delayed contraceptive initiation. We compared the risk of unwanted pregnancy for delayed versus timely contraceptive initiation.
We analyzed responses from 26 359 women with sexual debuts in 1970-2014. One in 5 overall and 1 in 4 African American, Hispanic, or low-income respondents reported delayed contraceptive initiation, which was associated with unwanted pregnancy within 3 months of sexual debut (adjusted risk ratio 3.7 versus timely contraceptive initiation; 99.9% confidence interval: 2.3-5.9; < .001). Timely contraceptive initiation with less effective versus effective methods was not associated with unwanted pregnancy within 3 months.
Delayed contraceptive initiation is more common among African American, Hispanic, and low-income women and is strongly associated with short-term risk of unwanted pregnancy. Pediatricians play a key role in making timely contraception available to adolescents at or before sexual debut. More research is needed to understand the importance of early contraceptive methods on pregnancy risk.
及时避孕的做法越来越普遍，但关于不同避孕方法和不同妊娠意外风险亚组的人群趋势尚未得到充分描述。避孕起始时间和类型对意外妊娠风险的影响尚不清楚。
我们使用了 2002-2015 年全国家庭增长调查的 4 个周期的全国代表性横断面数据。我们根据自我报告的首次性行为、避孕起始和意外妊娠日期计算了结果。我们比较了不同方法和种族/族裔及收入群体及时避孕起始（在首次性行为后 1 个月内）的趋势。使用多变量回归，我们确定了避孕起始延迟的预测因素。我们比较了避孕起始延迟与及时避孕起始的意外妊娠风险。
我们分析了 1970-2014 年首次性行为的 26359 名女性的回复。总体而言，1/5 的受访者和 1/4 的非裔美国人、西班牙裔或低收入受访者报告避孕起始延迟，这与首次性行为后 3 个月内的意外妊娠有关（调整风险比为 3.7；99.9%置信区间：2.3-5.9；<0.001）。及时避孕起始但使用的方法效果较差与首次性行为后 3 个月内意外妊娠无关。
避孕起始延迟在非裔美国人、西班牙裔和低收入女性中更为常见，与短期意外妊娠风险密切相关。儿科医生在青少年首次性行为时或之前提供及时避孕方面发挥着关键作用。需要进一步研究来了解早期避孕方法对妊娠风险的重要性。
