Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
Pediatr Allergy Immunol. 2011 Aug;22(5):528-36. doi: 10.1111/j.1399-3038.2010.01135.x. Epub 2011 Feb 7.
Oral contraceptive pills (OCPs) are often used soon before, and sometimes during, pregnancy. A few studies have suggested that OCP use before pregnancy may increase risks for childhood respiratory outcomes, but data are inconclusive. No studies have analyzed the two types of OCPs, estrogen-progestin combined pills and progestin-only pills, separately.
In the Norwegian Mother and Child Cohort Study (MoBa), we prospectively examined associations of OCP use before pregnancy, by type, with lower respiratory tract infections in 60,225 children followed to 6 months old, lower respiratory tract infections and wheezing in 42,520 children followed to 18 months old, and asthma in 24,472 children followed to 36 months old. We used logistic regression to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) crudely and with adjustment for a wide range of potential confounders.
Combined pills were used much more commonly than progestin-only pills. Taking combined pills before pregnancy was not associated with lower respiratory tract infections, wheezing, or asthma. Progestin-only pill use in the year before pregnancy had a slight positive association with wheezing at 6-8 months old [adjusted OR (95% CI) = 1.19 (1.05-1.34)].
Our finding that combined pill use before pregnancy was not related to respiratory outcomes should provide reassurance to the vast majority of mothers using OCPs before becoming pregnant. The small association with progestin-only pill use and early respiratory outcomes may reflect uncontrolled confounding or other bias. Nonetheless, it does suggest that these two types of pills should be examined separately in future analyses of respiratory and other childhood outcomes.
口服避孕药（OCP）通常在怀孕前或怀孕期间使用。一些研究表明，怀孕前使用 OCP 可能会增加儿童呼吸道疾病的风险，但数据尚无定论。没有研究分别分析雌激素-孕激素联合避孕药和单纯孕激素避孕药这两种类型的 OCP。
在挪威母亲和儿童队列研究（MoBa）中，我们前瞻性地研究了怀孕前使用 OCP 的情况，按类型分为 60225 名儿童在 6 个月大时，42520 名儿童在 18 个月大时，24472 名儿童在 36 个月大时发生下呼吸道感染、下呼吸道感染和喘息的情况。我们使用逻辑回归粗估和调整广泛潜在混杂因素后，估计了比值比（OR）及其 95%置信区间（CI）。
联合避孕药的使用比单纯孕激素避孕药更为常见。怀孕前服用联合避孕药与下呼吸道感染、喘息或哮喘无关。怀孕前一年使用单纯孕激素避孕药与 6-8 个月时喘息的轻度正相关有关[调整后的 OR（95%CI）=1.19（1.05-1.34）]。
我们发现怀孕前使用联合避孕药与呼吸道疾病结局无关，这应该让绝大多数怀孕前使用 OCP 的母亲感到放心。与单纯孕激素避孕药使用和早期呼吸道结局的轻微关联可能反映了无法控制的混杂因素或其他偏倚。尽管如此，这确实表明在未来对呼吸道和其他儿童结局的分析中，应分别对这两种类型的避孕药进行研究。
