WEDNESDAY, Nov. 14, 2018 (HealthDay News) -- Short intervals between pregnancies are associated with increased risks for adverse pregnancy outcomes for women of all ages, according to a study published online Oct. 29 in JAMA Internal Medicine.
Laura Schummers, S.D., from the Harvard T.H. Chan School of Public Health in Boston, and colleagues used data from a Canadian population-based cohort of women with at least two singleton pregnancies from 2004 to 2014 with the index pregnancy resulting in a live birth. The authors evaluated the association between a short interpregnancy (delivery to conception) interval and adverse pregnancy outcomes and aimed to determine whether it is modified by maternal age.
The researchers found that among 148,544 pregnancies, maternal mortality or severe morbidity risks were increased at six-month versus 18-month interpregnancy intervals for women ≥35 years (adjusted risk ratio [aRR], 2.39; 95 percent confidence interval [CI], 2.03 to 2.8) but not for women aged 20 to 34 years (aRR, 0.92; 95 percent CI, 0.83 to 1.02). For women aged 20 to 34 years, adverse fetal and infant outcome risks were more pronounced (aRR, 1.42; 95 percent CI, 1.36 to 1.47) versus women ≥35 years (aRR, 1.15; 95 percent CI, 1.01 to 1.31). Similarly, risks of spontaneous preterm delivery were increased for women 20 to 34 years old (aRR, 1.65; 95 percent CI, 1.62 to 1.68) and to a lesser extent for women ≥35 years (aRR, 1.4; 95 percent CI, 1.31 to 1.49) at six-month interpregnancy intervals. There was no meaningful difference based on maternal age in the modest increases in risks for small for gestational age and indicated preterm delivery.
"The findings of this study suggest that short interpregnancy intervals are associated with increased risks for adverse pregnancy outcomes for women of all ages," conclude the authors.