Agustin Conde-Agudelo, M.D., M.P.H., from the Fundación Santa Fe
de Bogotá, Columbia, and colleagues conducted a meta-analysis on
studies published between 1966 and 2006 to examine the
association between birth spacing and the risk of adverse
perinatal outcomes. The researchers identified 67 articles for
this analysis, which adjusted for the mother's age and
socioeconomic status and reported birth spacing and perinatal
outcomes. These articles included a total of 11,091,659
pregnancies. Infants born to women with an interval shorter than
six months after their last birth had a 40 percent increased
risk of preterm birth, a 61 percent increased risk of low birth
weight (LBW) and a 26 percent increased risk of small for
gestational age (SGA), compared to children of mothers with an
interval of 18 to 23 months between pregnancies. Infants of
mothers with pregnancy intervals longer than 59 months had a 20
to 43 percent greater risk of these adverse outcomes. For each
month that the time between pregnancies was sho