Shedding a few pounds isn't bad, but trying to lose weight before pregnancy could be bad news

To make this discovery, McMillen and colleagues examined the embryos conceived in four groups of female sheep. The first group of sheep was overnourished from four months before conception, until one week after conception. The second group of sheep was overnourished for three months and then placed on a diet for one month before and one week after conception. The third group of sheep was placed on a normal or control diet from four months before conception, until one week after conception. The fourth group was fed a control diet for three months and then these normal weight sheep were placed on a diet for one month before conception, until one week after conception. One week after conception, embryos from all of these sheep were transferred to normal weight, normally nourished sheep for the remainder of pregnancy. Liver samples were taken from the lambs born to these ewes at four months of age to examine their genes and proteins.
"This discovery helps us to understand how body weight affects our health and the health of our children—right down to the genetic level," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Clearly this effect in must be confirmed in humans, but the study should help us to optimize a hopeful mom's management of how and when to lose weight to have a healthy child."
Source-Eurekalert