\link{http://news.bbc.co.uk/1/hi/health/4918662.stm\Pregnancy gap adds risk to baby}
Summary:
Too short or long a gap between children increases the risk of problems for the second baby, research suggests.
An interval of less than 18 months and more than 59 months - just under five years - increases the risk, the Colombian researchers found.
"The results of our systematic review could be used by reproductive clinicians around the world to advise women on the benefits of delaying a subsequent pregnancy for approximately two to five years to improve the health of both mother and the next infant."