A prospective cohort study of a woman's own gestational age and her fecundability.
A prospective cohort study of a woman's own gestational age and her fecundability.
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一项针对女性自身胎龄及其生育能力的前瞻性队列研究。
DOI：
10.1093/humrep/dev007
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Mikkelsen,EM
中科院分区：
文献类型：
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作者：
Wildenschild,C;Riis,AH;Ehrenstein,V;Hatch,EE;Wise,LA;Rothman,KJ;Sørensen,HT;Mikkelsen,EM
研究问题妇女出生时的胎龄和她的生育能力（周期特异性受孕概率）之间的关联程度如何？概要回答我们发现，相对于孕37-41周出生的妇女，孕34周以下出生的妇女的生育能力下降了62%，而孕龄较晚的妇女的生育能力几乎没有差异。发现在小于37孕周（早产）和出生体重≤1500 g的妇女中TTP延长。其他关于女性出生时的胎龄和随后的生育能力的研究，基于国家出生登记处的数据，已经报道了出生时<32周妊娠的女性分娩的概率降低。研究设计，规模，持续时间我们使用了来自丹麦怀孕计划者（'Snart-Gravid'）的前瞻性队列研究的数据，在2007-2011年期间登记，并随访至2012年。在所有，2814名妇女参加了我们的研究，其中2569人有完整的follow-up. PARTICANTANTS/材料，设置，METHODS妇女资格参加18-40岁的研究进入，在与男性伴侣的关系，并试图怀孕。参与者完成了一份基线调查问卷和最多6份随访调查问卷，直到报告怀孕、终止怀孕尝试、开始生育治疗、失去随访或12个月后研究观察结束。主要结果和机会的作用在出生<34孕周的妇女中，3周内的累积受孕概率分别为12、28和48%，分别为6和12个周期。在妊娠37-41周出生的妇女中，在3、6和12个周期内的累积受孕概率分别为47%、67%和84%。相对于孕37-41周出生的妇女，<34周出生的妇女具有降低的生育力（生育力比（FR）0.38，95%置信区间（CI）：0.17-0.82）。我们的数据并没有表明妊娠34-36周或妊娠≥42周的妇女生育能力降低（FR 1.03，95% CI：0.80-1.34，和FR 1.13，95% CI：0.96-1.33）。限制，放弃的原因关于胎龄的数据，从丹麦医学出生登记处获得，与早期超声检查相比，更有可能基于末次月经日期，这可能导致高估出生时的胎龄。然而，这种高估并不能解释在小于34孕周出生的妇女中观察到的生育能力下降。另一个局限性是，在我们的研究人群中，妊娠34周前出生的妇女比例较低，这降低了估计的精度。这表明妊娠期<34周的妇女生育能力降低。研究资金/竞争兴趣（S）这项研究得到了国家儿童健康和人类发展研究所的支持（R21-050264）、丹麦医学研究理事会（271-07-0338）和中央丹麦地区健康研究基金（1-01-72-84-10）。作者没有要申报的竞争利益。
STUDY QUESTIONWhat is the magnitude of the association between a woman's gestational age at her own birth and her fecundability (cycle-specific probability of conception)?SUMMARY ANSWERWe found a 62% decrease in fecundability among women born <34 weeks of gestation relative to women born at 37–41 weeks of gestation, whereas there were few differences in fecundability among women born at later gestational ages.WHAT IS KNOWN ALREADYOne study, using retrospectively collected data on time-to-pregnancy (TTP), and self-reported data on gestational age, found a prolonged TTP among women born <37 gestational weeks (preterm) and with a birthweight ≤1500 g. Other studies of women's gestational age at birth and subsequent fertility, based on data from national birth registries, have reported a reduced probability of giving birth among women born <32 weeks of gestation.STUDY DESIGN, SIZE, DURATIONWe used data from a prospective cohort study of Danish pregnancy planners (‘Snart-Gravid’), enrolled during 2007–2011 and followed until 2012. In all, 2814 women were enrolled in our study, of which 2569 had complete follow-up.PARTICIPANTS/MATERIALS, SETTING, METHODSWomen eligible to participate were 18–40 years old at study entry, in a relationship with a male partner, and attempting to conceive. Participants completed a baseline questionnaire and up to six follow-up questionnaires until the report of pregnancy, discontinuation of pregnancy attempts, beginning of fertility treatment, loss to follow-up or end of study observation after 12 months.MAIN RESULTS AND THE ROLE OF CHANCEAmong women born <34 gestational weeks, the cumulative probability of conception was 12, 28 and 48% within 3, 6 and 12 cycles, respectively. Among women born at 37–41 weeks of gestation, cumulative probability of conception was 47, 67 and 84% within 3, 6 and 12 cycles, respectively. Relative to women born at 37–41 weeks' gestation, women born <34 weeks had decreased fecundability (fecundability ratio (FR) 0.38, 95% confidence interval (CI): 0.17–0.82). Our data did not suggest reduced fecundability among women born at 34–36 weeks of gestation or at ≥42 weeks of gestation (FR 1.03, 95% CI: 0.80–1.34, and FR 1.13, 95% CI: 0.96–1.33, respectively).LIMITATIONS, REASONS FOR CAUTIONData on gestational age, obtained from the Danish Medical Birth Registry, were more likely to be based on date of last menstrual period than early ultrasound examination, possibly leading to an overestimation of gestational age at birth. Such overestimation, however, would not explain the decrease in fecundability observed among women born <34 gestational weeks. Another limitation is that the proportion of women born before 34 weeks of gestation was low in our study population, which reduced the precision of the estimates.WIDER IMPLICATIONS OF THE FINDINGSBy using prospective data on TTP, our study elaborates on previous reports of impaired fertility among women born preterm, suggesting that women born <34 weeks of gestation have reduced fecundability.STUDY FUNDING/COMPETING INTEREST(S)The study was supported by the National Institute of Child Health and Human Development (R21-050264), the Danish Medical Research Council (271-07-0338), and the Health Research Fund of Central Denmark Region (1-01-72-84-10). The authors have no competing interests to declare.