使用自然计划生育期间怀孕的受孕时间与自然流产风险

Timing of conception and the risk of spontaneous abortion among pregnancies occurring during the use of natural family planning.

作者信息

Gray R H, Simpson J L, Kambic R T, Queenan J T, Mena P, Perez A, Barbato M

机构信息

Department of Population Dynamics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.

出版信息

Am J Obstet Gynecol. 1995 May;172(5):1567-72. doi: 10.1016/0002-9378(95)90498-0.

DOI:10.1016/0002-9378(95)90498-0

PMID:7755073

Abstract

OBJECTIVE

Our purpose was to ascertain the effects of timing of conception on the risk of spontaneous abortion.

STUDY DESIGN

To assess these effects, women who conceived while using natural family planning were identified in five centers worldwide between 1987 and 1993. Timing of conception was determined from 868 natural family planning charts that recorded day of intercourse and indices of ovulation (cervical mucus peak obtained according to the ovulation method and/or basal body temperature). Conceptions on days - 1 or 0 with respect to the natural family planning estimated day of ovulation were considered to be "optimally timed," and all other conceptions were considered as "non-optimally timed." The rate of spontaneous abortions per 100 pregnancies was examined in relation to timing of conception, ages, reproductive history, and other covariates with bivariate and multivariate statistical methods.

RESULTS

There were 88 spontaneous abortions among 868 pregnancies (10.1%). The spontaneous abortion rate was similar for 361 optimally timed conceptions (9.1%) and 507 non-optimally timed conceptions (10.9%). However, among 171 women who had experienced a spontaneous abortion in a prior pregnancy, the rate of spontaneous abortion in the index pregnancy was significantly higher with non-optimally timed conceptions (22.6%) as compared with optimally timed conceptions (7.3%). This association was not observed among 697 women with no history of pregnancy loss. The adjusted relative risk of spontaneous abortion among women with non-optimally timed conceptions and a history of pregnancy loss was 2.35 (95% confidence intervals 1.42 to 3.89). The excess risk of spontaneous abortion was observed with both preovulatory and postovulatory conceptions.

CONCLUSIONS

Overall, there is no excess risk of spontaneous abortion among the pregnancies conceived during natural family planning use. However, among women with a history of pregnancy loss, there is an increased risk of spontaneous abortion associated with preovulatory or postovulatory delayed conceptions.

摘要

目的

我们的目的是确定受孕时间对自然流产风险的影响。

研究设计

为评估这些影响，1987年至1993年间在全球五个中心识别出采用自然计划生育时受孕的女性。受孕时间根据868份自然计划生育图表确定，这些图表记录了性交日期和排卵指标（根据排卵方法获得的宫颈黏液峰值和/或基础体温）。相对于自然计划生育估算的排卵日，在第-1天或第0天受孕被视为“最佳受孕时间”，所有其他受孕被视为“非最佳受孕时间”。采用双变量和多变量统计方法，研究每100次妊娠的自然流产率与受孕时间、年龄、生殖史及其他协变量之间的关系。

结果

868例妊娠中有88例自然流产（10.1%）。361例最佳受孕时间的妊娠自然流产率（9.1%）与507例非最佳受孕时间的妊娠自然流产率（10.9%）相似。然而，在171例既往有自然流产史的女性中，此次妊娠非最佳受孕时间的自然流产率（22.6%）显著高于最佳受孕时间的自然流产率（7.3%）。在697例无妊娠丢失史的女性中未观察到这种关联。有非最佳受孕时间且有妊娠丢失史的女性自然流产的校正相对风险为2.35（95%置信区间1.42至3.89）。排卵前和排卵后受孕均观察到自然流产的额外风险。