Xiu SiQin, Tang Li, Qin Chengjie, Tian Di, Chen Yuhong, Gu Lingling, Yang Liu, Sun Yuhao, Liu Xinghui, Lin Yonghong, Wang Yumei
Department of Gynecology and Obstetrics, School of Medicine, Chengdu Women's and Children's Central Hospital, University of Electronic Science and Technology of China, Chengdu, China.
Department of Health Care, School of Medicine, Chengdu Women's and Children's Central Hospital, University of Electronic Science and Technology of China, Chengdu, China.
BMC Pregnancy Childbirth. 2025 Jan 27;25(1):81. doi: 10.1186/s12884-025-07136-8.
Since the implementation of China's comprehensive two-child policy, the prevalence of long interpregnancy intervals (IPI) and advanced maternal age has increased. However, previous studies in China have mostly focused on the relationship between short IPIs and adverse perinatal outcomes, while neglecting maternal age as a potential confounder.
We conducted a retrospective cohort study of 23,899 pregnant women who delivered between January 1, 2017 and December 31, 2019 at Chengdu Women's and Children's Central Hospital and West China Second Hospital of Sichuan University. IPIs were categorized as < 18 months, 18-23 months, 24-59 months, 60-119 months, and ≥ 120 months. Their relationships with clinical characteristics and pregnancy outcomes were analyzed using chi-square tests and Cochran-Armitage test for trend. Logistic regression modeling, incorporating restricted cubic spline (RCS), was used to assess association between IPI and adverse perinatal outcomes, including full-term low birthweight (LBW), preterm birth (PTB), small-for-gestational age (SGA) and adverse neonatal composite (very low birthweight, very preterm birth, severe neonatal asphyxia or death).
Women with longer IPIs (≥ 120 months) were more likely to be older (≥ 35 years) and had higher rates of gestational diabetes and hypertensive disorders of pregnancy (p < 0.05). Compared to an IPI of 24-59 months, the risk of PTB was significantly higher with an IPI of ≥ 120 months for women aged ≥ 35 years (aOR,1.17; 95% CI, 0.89-1.55) and 30-34 years (aOR 2.17; 95% CI, 1.59-2.92), but not for those aged ≤ 29 years (aOR 1.34; 95% CI, 0.20-5.31). The risk of SGA increased with an IPI of ≥ 120 months for women aged 30-34 years (aOR, 2.19; 95% CI, 0.97-4.53) and with an IPI of 60-119 months for women aged ≤ 29 years (aOR,3.16; 95% CI, 1.62-6.30). Full-term LBW risk was elevated among women aged ≤ 29 years with an IPI of ≥ 120 months (aOR, 10.42; 95% CI, 0.55-59.52). However, there were no significant differences in the risk of adverse neonatal composite across different IPI groups with each age category (p > 0.05).
A long IPI increased the risk of SGA, full-term LBW and PTB, regardless of maternal age. Medical professionals should advise women an optimal IPI to mitigate these risks. With China's shift from a "one-child" to a "three-child" policy, future research will focus on analyzing this new fertility pattern to refine IPI recommendations.
自中国实施全面二孩政策以来，较长的妊娠间隔（IPI）和高龄产妇的患病率有所增加。然而，中国以往的研究大多集中在短IPI与不良围产期结局之间的关系，而忽视了产妇年龄作为一个潜在的混杂因素。
我们对2017年1月1日至2019年12月31日在成都市妇女儿童中心医院和四川大学华西第二医院分娩的23899名孕妇进行了一项回顾性队列研究。IPI被分为<18个月、18 - 23个月、24 - 59个月、60 - 119个月和≥120个月。使用卡方检验和趋势Cochran - Armitage检验分析它们与临床特征和妊娠结局的关系。采用包含受限立方样条（RCS）的逻辑回归模型评估IPI与不良围产期结局之间的关联，不良围产期结局包括足月低出生体重（LBW）、早产（PTB）、小于胎龄儿（SGA）和不良新生儿综合结局（极低出生体重、极早产、严重新生儿窒息或死亡）。
IPI较长（≥120个月）的女性更有可能年龄较大（≥35岁），且妊娠期糖尿病和妊娠高血压疾病的发生率较高（p<0.05）。与IPI为24 - 59个月相比，年龄≥35岁（调整后比值比[aOR]，1.17；95%置信区间[CI]，0.89 - 1.55）和30 - 34岁（aOR 2.17；95% CI，1.59 - 2.92）的女性，IPI≥120个月时PTB风险显著更高，但年龄≤29岁的女性并非如此（aOR 1.34；95% CI，0.20 - 5.31）。对于30 - 34岁的女性，IPI≥120个月时SGA风险增加（aOR，2.19；95% CI，0.97 - 4.53），而对于年龄≤29岁的女性，IPI为60 - 119个月时SGA风险增加（aOR，3.16；95% CI，1.62 - 6.30）。年龄≤29岁且IPI≥120个月的女性足月LBW风险升高（aOR，10.42；95% CI，0.55 - 59.52）。然而，不同年龄组中不同IPI组的不良新生儿综合结局风险无显著差异（p>0.05）。
无论产妇年龄如何，较长的IPI都会增加SGA、足月LBW和PTB的风险。医学专业人员应建议女性选择最佳的IPI以降低这些风险。随着中国从“一孩”政策向“三孩”政策转变，未来的研究将集中分析这种新的生育模式，以完善IPI建议。
