Short Pregnancy Intervals May Shorten Pregnancy Lengths
(HealthDay News) — Short interpregnancy interval (IPI) is associated with shortened duration of the subsequent pregnancy, according to research published online June 4 in BJOG: An International Journal of Obstetrics and Gynaecology.
Emily A. DeFranco, MD, of the University of Cincinnati, and colleagues conducted a population-based retrospective cohort study of 454,716 live births to multiparous mothers to assess the influence of inadequate birth spacing on birth timing distribution across gestation. The researchers defined short IPI as time from the immediate preceding birth to subsequent conception of the index pregnancy of less than six months, 6–<12 months, and 12–<18 months.
The researchers found that 87% of births followed a normal IPI of ≥18 months, 10.7% had an IPI of 12–18 months, and 2.2% had an IPI <12 months. The risk of delivery at <39 weeks of gestation was higher following an IPI of <12 months compared with a normal IPI (53.3 vs. 37.5%; adjusted odds ratio [AOR], 2.78; 95% confidence interval [CI], 2.64–2.93). The risk of delivery at ≥40 weeks of gestation was lower following an IPI of <12 months compared with a normal IPI (16.9 vs. 23.2%; AOR, 0.67; 95% CI, 0.64≥0.71).
"Short intervals between pregnancies result in decreased pregnancy length with more deliveries at all gestational ages prior to 39 weeks, and fewer at 40 weeks and beyond," the authors write.