Babies are considered "full term" at 37 weeks of pregnancy. But new research findings have shed more evidence that continuing a pregnancy to at least 39 weeks is vital to a baby's health.

Adding just a few more weeks of pregnancy can cut a newborn's risk of death in half -- even if the pregnancy has reached "term", according to a research by March of Dimes, the leading nonprofit organization for pregnancy and baby health.

Although the overall risk of death is small, it more than doubles for infants born at 37 weeks of pregnancy, compared to babies born at 40 weeks, across all races and ethnicities. From 37 weeks, neonatal infant mortality rates declined for each additional week until 40 weeks, which had the lowest death rates.

"There is the perception that babies born between 37 and 41 weeks of pregnancy are all born healthy. But this study confirms that even babies born just a week or two early have an increased risk of death," says Alan Fleischman, MD, senior vice president and medical director at the March of Dimes.

And while there are times when medical reasons necessitate the early delivery of a baby, an elective delivery should never be scheduled before 39 or 40 weeks of pregnancy. "It is clear, that regardless of race or ethnicity, every additional week of pregnancy is critical to a baby's health," adds Fleischman.