School of Public Health, Curtin University, Bentley, Western Australia, Australia.
School of Nursing, Midwifery and Paramedicine, Curtin University, Bentley, Western Australia, Australia.
Am J Epidemiol. 2019 Jan 1;188(1):9-16. doi: 10.1093/aje/kwy188.
The association between a single interpregnancy interval (IPI) and birth outcomes has not yet been explored using matched methods. We modeled the odds of preterm birth, being small for gestational age, and having low birth weight in a second, live-born infant in a cohort of 192,041 sibling pairs born in Western Australia between 1980 and 2010. The association between IPI and birth outcomes was estimated from the interaction between birth order and IPI (with 18-23 months as the reference category), using conditional logistic regression. Matched analysis showed the odds of preterm birth were higher for siblings born following an IPI of <6 months (adjusted interaction odds ratio = 1.22, 95% confidence interval: 1.06, 1.38) compared with those born after an IPI of 18-23 months. There were no significant differences for IPIs of <6 months for other outcomes (small for gestational age or low birth weight). This is the first study to use matched analyses to investigate the association between a single IPI on birth outcomes. IPIs of <6 months were associated with increased odds of preterm birth in second-born infants, although the association is likely smaller than previously estimated by unmatched studies.
利用匹配方法研究单一孕期间隔（IPI）与分娩结局之间的关系尚未得到探索。我们对 1980 年至 2010 年在澳大利亚西部出生的 192041 对兄弟姐妹队列中的第二胎活产儿早产、小于胎龄儿和低出生体重的几率进行了建模。利用条件逻辑回归，从出生顺序与 IPI 的相互作用（以 18-23 个月为参考类别）估计 IPI 与分娩结局之间的关联。匹配分析显示，与出生于 18-23 个月 IPI 的婴儿相比，出生于 IPI<6 个月的婴儿早产的几率更高（调整后的相互作用比值比=1.22，95%置信区间：1.06，1.38）。对于小于胎龄儿或低出生体重儿等其他结局，IPIs<6 个月没有显著差异。这是第一项使用匹配分析研究单一 IPI 对分娩结局影响的研究。IPIs<6 个月与第二胎婴儿早产的几率增加有关，但与以前非匹配研究估计的关联可能较小。
