Abstract
Objective To examine the relationship of subfertility with miscarriage, low birth weight, and preterm delivery.
Design Comparison of time to pregnancy distributions between pregnancies that had different outcomes. Three comparisons were made: (a) miscarriages with live births; within live births, (b) low birth weight infant (up to 2,500 grams) or not low birth weight; (c) preterm birth (37 weeks or less) or not preterm. Cox regression was used to adjust for covariates.
Population All first pregnancies were analyzed from the National Child Development Study, a large survey of young adults aged 33 years, which is nationally representative of the British-born population.
Main Outcome Measures The distribution of the time taken to conceive (time to pregnancy), miscarriage, birth weight, and preterm delivery.
Results Pregnancies that ended in miscarriage tended to take 23% longer to conceive, after adjustment for the other variables. Pregnancies that resulted in preterm delivery tended to take 15% longer to conceive. There was no statistically significant association with low birth weight.
Conclusions Delay in time to conception is a risk factor for poor obstetric outcome, irrespective of medical intervention.
time to pregnancy subfertility miscarriage risk association, delayed conception preterm delivery poor obstetric outcome, time to pregnancy low birth weight preterm birth, subfertility fecundability pregnancy outcome retrospective cohort, National Child Development Study time to pregnancy UK, conception delay miscarriage risk Cox regression analysis, subfertility as risk factor adverse pregnancy outcomes, fecundity pregnancy loss epidemiology population-based study, time to pregnancy distribution miscarriage live birth comparison, Joffe Li time to pregnancy obstetric outcome
PMID 8005307 8005307 DOI 10.1016/s0015-0282(16)56818-6 10.1016/s0015-0282(16)56818-6
Keywords
Abortion, Spontaneous/epidemiology, Cohort Studies, Female, Humans, Infant, Low Birth Weight, Infant, Newborn, Infertility, Female/physiopathology, Obstetric Labor, Premature/epidemiology, Odds Ratio, Pregnancy, Pregnancy Outcome, Risk Factors, Time Factors, Age Factors, Behavior, Biology, Birth Weight, Body Weight, Demographic Factors, Developed Countries, Economic Factors, Educational Status, Europe, Fertility, Fertility Measurements, Fetal Death, First Pregnancy Intervals, Low Birth Weight, Maternal Age, Mortality, Northern Europe, Parental Age, Physiology, Population, Population Characteristics, Population Dynamics, Pregnancy, Pregnancy Intervals, Pregnancy Outcomes--determinants, Reproduction, Risk Factors, Smoking, Socioeconomic Factors, Socioeconomic Status, Time Factors, United Kingdom