CONCLUSIONS: The couple\'s age range of optimal fecundability and age combinations differed with gravidity, and gravidity might modify the associations of age and spousal age difference with couple\'s fecundability.
BACKGROUND: Age is one of the strongest determinants of fecundability, but the existing studies have certain limitations in study population, couple\'s extreme age combinations and age differences, and have not explored whether the association between age and fecundability differs with gravidity.
METHODS: Retrospective cohort study. 5 407 499 general reproductive-aged couples (not diagnosed with infertility) participated in the National Free Pre-conception Check-up Projects during 2015-2017. They were followed up for pregnancy outcomes through telephone interviews every 3 months until they became pregnant or were followed up for 1 year.
METHODS: The main outcome was time to pregnancy, and the fecundability odds ratios and 95% CIs were estimated using the Cox models for discrete survival time. The associations of age and spousal age difference with fecundability were evaluated by restricted cubic splines.
RESULTS: In this large cohort of general reproductive-aged population, the age of optimal fecundability of multigravida couples was older than that of nulligravida couples, but their subsequent fecundability declined more sharply with age. The decline in female fecundability was more pronounced with age, with fecundability dropping by ∼30% in both nulligravida and multigravida couples whose female partners aged ≥35 years. In the nulligravida group, the fecundability of couples who were both ≤24 years with the same age was the highest, which decreased steadily with the increase of spousal age difference, and younger male partners did not seem to contribute to improving couple\'s fecundability. In the multigravida group, couples with female partners aged 25-34 years and a spousal age difference of -5 to 5 years showed higher fecundability, and the effect of spousal age difference on couple\'s fecundability became suddenly apparent when female partners aged around 40 years. Young male partners were unable to change the decisive effect of female partner\'s age over 40 years on couple\'s reduced fecundability, regardless of gravidity.
CONCLUSIONS: Lacking the time for couples to attempt pregnancy before enrollment, and some couples might suspend pregnancy plans during follow-up because of certain emergencies, which would misestimate the fecundability. Due to the lack of information on sperm quality and sexual frequency of couples, we could not adjust for these factors. Moreover, due to population characteristics, the extrapolation of our results required caution.
CONCLUSIONS: The couple\'s age range of optimal fecundability, age combinations, and spousal age difference on fecundability varied with gravidity. Female age-related decline in fecundability was more dominant in couple\'s fecundability. Targeted fertility guidance should be provided to couples with different age combinations and gravidities.
BACKGROUND: This research received funding from the Project of National Research Institute for Family Planning (Grant No. 2018NRIFPJ03), the National Key Research and Development Program of China (Grant No. 2016YFC1000307), and the National Human Genetic Resources Sharing Service Platform (Grant No. 2005DKA21300), People\'s Republic of China. The funders had no role in study design, analysis, decision to publish, or preparation of the manuscript. The authors report no conflict of interest.
BACKGROUND: N/A.
结论:夫妇的最佳可育性的年龄范围和年龄组合与妊娠不同,妊娠可能会改变年龄和配偶年龄差异与夫妻生育能力的关系。
背景:年龄是决定可育性的最强因素之一,但是现有的研究在研究人群中存在一定的局限性,夫妇的极端年龄组合和年龄差异,并且尚未探讨年龄和可育性之间的关联是否随妊娠而不同。
方法:回顾性队列研究。5407499对普通育龄夫妇(未诊断为不孕症)在2015-2017年期间参加了国家免费孕前检查项目。每3个月通过电话采访对他们的妊娠结局进行随访,直到他们怀孕或随访1年。
方法:主要结局是怀孕时间,使用Cox模型对离散生存时间进行了可产性比值比和95%CI的估计。通过有限的三次样条曲线评估了年龄和配偶年龄差异与生育能力的关系。
结果:在这一庞大的普通育龄人群中,多胎夫妇的最佳可育年龄比无胎夫妇的年龄大,但它们随后的可育性随着年龄的增长而急剧下降。随着年龄的增长,女性的可育性下降更为明显,女性伴侣年龄≥35岁的nulligravida和multigravida夫妇的可育性下降了30%。在nulligravida组中,年龄均≤24岁的夫妇的可育性最高,随着配偶年龄差异的增加,和年轻的男性伴侣似乎并没有有助于提高夫妇的生育能力。在多重妊娠组,女性伴侣年龄在25-34岁,配偶年龄差异在-5至5岁之间的夫妇表现出更高的生育能力,当女性伴侣年龄在40岁左右时,配偶年龄差异对夫妻生育能力的影响突然变得明显。年轻的男性伴侣无法改变女性伴侣年龄超过40岁对夫妇生育能力降低的决定性影响,不管妊娠。
结论:夫妇在入学前没有尝试怀孕的时间,一些夫妇可能会因为某些紧急情况而在随访期间暂停怀孕计划,这将错误估计可繁殖性。由于缺乏有关夫妻精子质量和性频率的信息,我们无法适应这些因素。此外,由于人口特征,对我们结果的推断需要谨慎。
结论:夫妇的最佳可育年龄范围,年龄组合,生育能力的配偶年龄差异随妊娠而变化。女性年龄相关的可育性下降在夫妇的可育性中占主导地位。应向不同年龄组合和妊娠的夫妇提供有针对性的生育指导。
背景:这项研究获得了国家计划生育研究所项目的资助(批准号:2018NRIFPJ03),国家重点研究发展计划(批准号:2016YFC1000307),和国家人类遗传资源共享服务平台(批准号:2005DKA21300),中华人民共和国。资助者在研究设计中没有作用,分析,决定发布,或准备手稿。作者报告没有利益冲突。
背景:不适用。