Luderer U, Li T, Fine J P, Hamman R F, Stanford J B, Baker D
Division of Occupational and Environmental Medicine, Department of Medicine, University of California Irvine, Irvine, CA 92617, USA.
Westat, Rockville, MD 20850, USA.
Hum Reprod. 2017 Jun 1;32(6):1325-1333. doi: 10.1093/humrep/dex065.
Do the rates at which women transition among different intensities of pregnancy planning vary with age, marital status and race/ethnicity?
Rates of transition from low or moderate pregnancy probability groups (PPGs) to higher PPGs vary by age, marital status and race/ethnicity.
The design of prospective studies of the effects of pre- and peri-conception exposures on fecundity, pregnancy and children's health is challenging because at any specific time only a small percentage of reproductive age women is attempting to conceive. To our knowledge, there has been no population-based, prospective study that repeatedly assessed pregnancy planning, which included women who were not already planning pregnancy at enrollment and whose ages spanned the female reproductive age range.
STUDY DESIGN, SIZE, DURATION: A longitudinal study was carried out that repeatedly assessed pregnancy probability in 12 916 women for up to 21 months from January 2009 to September 2010.
PARTICIPANTS/MATERIALS, SETTING, METHOD: We analyzed data from the National Children's Study Vanguard Study, a pilot study for a large-scale epidemiological birth cohort study of children and their parents. During the Vanguard Study, investigators followed population-based samples of reproductive age women in each of seven geographically dispersed and diverse study locations over time to identify when they sought to become pregnant, providing a unique opportunity to prospectively assess changes in pregnancy planning in a large sample of US women. At study entry and each follow-up contact, which occurred at 1, 3 or 6 month intervals depending on PPG, a questionnaire was used to assess behavior dimensions of pregnancy planning to assign women to low, moderate, high non-tryer and high tryer PPGs.
Crude rates of pregnancy increased with higher assigned PPG, validating the utility of the instrument. The initial PPG and probabilities of transitioning from low or moderate PPG to higher PPG or pregnancy varied with age, marital status and race/ethnicity. Women aged 25 to <35 years had shorter times to transition to higher PPGs or to pregnant compared with women <25 years. Women who were not currently married had longer times to transition from any initial PPG to pregnant, high tryer or high non-tryer status than currently married women. Non-Hispanic Black (NHB) and Hispanic women had shorter time to transition from low or moderate to high non-tryer than non-Hispanic White (NHW) women. NHB women also had shorter time to transition from low to high tryer than NHW women. High tryers are more likely to be aged 25 to <30 years, to be married, and to be Hispanic, NHB or other race/ethnicity than women in the low PPG.
LIMITATIONS, REASONS FOR CAUTION: Loss to follow-up varied by age, marital status and race/ethnicity. Although weights were not developed for the Vanguard study, the self-weighting design minimizes the bias of unweighted analysis. Nonetheless, the SEs for some estimates may be under-estimated.
Our results show that demographic characteristics are strong predictors of women's behaviors toward pregnancy. The results further show that frequent follow-up assessments of pregnancy planning behavior in large numbers of women are required to recruit an unbiased sample of preconception women. These findings will be useful to investigators designing prospective studies of fecundability, pregnancy outcomes and children's health.
STUDY FUNDING/COMPETING INTERESTS: National Institutes of Health (contracts N01-HD53414, N01-HD63416, N01-HD53410, N01-HD53415, N01-HD53396, N01-HD53413 and N01-HD-53411; grant R21 ES016846) and by the University of California Irvine Center for Occupational and Environmental Health. No competing interests.
None.
女性在不同强度的妊娠计划之间转换的比率是否会因年龄、婚姻状况和种族/民族而有所不同？
从低或中度妊娠概率组（PPG）转换到较高PPG的比率因年龄、婚姻状况和种族/民族而异。
孕前和孕期暴露对生育力、妊娠及儿童健康影响的前瞻性研究设计具有挑战性，因为在任何特定时间，只有一小部分育龄女性试图怀孕。据我们所知，尚无基于人群的前瞻性研究对妊娠计划进行反复评估，该研究应纳入在入组时未计划怀孕且年龄涵盖女性生殖年龄范围的女性。
研究设计、规模、持续时间：开展了一项纵向研究，从2009年1月至2010年9月，对12916名女性进行了长达21个月的反复妊娠概率评估。
参与者/材料、地点、方法：我们分析了来自国家儿童研究先锋研究的数据，这是一项针对儿童及其父母的大规模流行病学出生队列研究的试点研究。在先锋研究期间，研究人员随着时间推移，对七个地理上分散且多样化的研究地点的基于人群的育龄女性样本进行跟踪，以确定她们何时试图怀孕，这为前瞻性评估大量美国女性妊娠计划的变化提供了独特机会。在研究入组时以及根据PPG每隔1、3或6个月进行的每次随访中，使用问卷评估妊娠计划的行为维度，以将女性分配到低、中、高非尝试者和高尝试者PPG组。
随着PPG的升高，粗略妊娠率增加，验证了该工具的效用。初始PPG以及从低或中度PPG转换到较高PPG或怀孕的概率因年龄、婚姻状况和种族/民族而异。与25岁以下的女性相比，25至<35岁的女性转换到较高PPG或怀孕的时间更短。与目前已婚的女性相比，目前未婚的女性从任何初始PPG转换到怀孕、高尝试者或高非尝试者状态的时间更长。非西班牙裔黑人（NHB）和西班牙裔女性从低或中度转换到高非尝试者的时间比非西班牙裔白人（NHW）女性短。NHB女性从低转换到高尝试者的时间也比NHW女性短。与低PPG组的女性相比，高尝试者更可能年龄在25至<30岁之间、已婚，并且是西班牙裔、NHB或其他种族/民族。
局限性、谨慎理由：随访失访率因年龄、婚姻状况和种族/民族而异。尽管未为先锋研究制定权重，但自加权设计可将未加权分析的偏差降至最低。尽管如此，某些估计值的标准误可能被低估。
我们的结果表明，人口统计学特征是女性妊娠行为的有力预测因素。结果还进一步表明，需要对大量女性的妊娠计划行为进行频繁的随访评估，以招募无偏差的孕前女性样本。这些发现将有助于设计生育力、妊娠结局和儿童健康前瞻性研究的研究人员。
研究资金/利益冲突：美国国立卫生研究院（合同编号N01 - HD53414、N01 - HD63416、N01 - HD53410、N01 - HD53415、N01 - HD53396、N01 - HD53413和N01 - HD - 53411；资助编号R21 ES016846）以及加利福尼亚大学欧文分校职业与环境卫生中心。无利益冲突。
无。
