Association of time to pregnancy and the outcome of pregnancy
Joffe, M.; Li, Z.
Fertility and Sterility 62(1): 71-75
1994
ISSN/ISBN: 0015-0282 PMID: 8005307 DOI: 10.1016/s0015-0282(16)56818-6Document Number: 289102
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.