Gap in pregnancies and stillborn risk

New research suggests that women who wait at least six years to have another baby may have a higher risk of having a stillborn child. It was found that mothers who separated their children by an interval of at least six years were 50 percent more likely to have a stillborn child, relative to women who waited for one to three years between children.Previous research has suggested that both waiting too long and not waiting long enough to have a second child increase the risk of certain negative outcomes, including low birth weight and premature delivery.Researchers at the Karolinska Institute in Stockholm, Sweden, reviewed the outcomes of two consecutive deliveries of 410,021 women who gave birth in Sweden between 1983 and 1997. Specifically, the researchers measured whether particularly small or large intervals between two pregnancies increased the risk of early infant death or having a stillborn baby.The results showed that women who waited at least six years or less than three months to have a second child appeared to be more at risk of adverse outcomes. Long-interval mothers were at higher risk of having a stillborn baby, while short-interval mothers were more at risk of having a stillborn baby or a baby that died during the first few days of life. However, once the researchers took in to account certain characteristics of mothers that could affect the health of the pregnancy - such as outcome of her first birth, and whether or not she smoked or had diabetes - they found that having only a short interval between pregnancies appeared to have no influence on the risk of having a stillborn baby or early infant death.The association between long intervals and stillbirth may be attributed to metabolic or anatomical factors that are associated with delayed fertility as well as adverse birth outcomes.