American Pittsburgh medical treatment center of Pennsylvania two researcher discovers recently, to compare with it, those females who conceive in spring conceive in three other seasons, alter at gestation not enough 37 weeks born a premature infant.Researcher to in 1995-2005 years at the same house of obstetrics and gynecology hospital 75399 women of the childbearing give birth to baby a record to carry on analysis discover, be pregnant in spring of the female born the premature infant's several rates tallest, the women, who be pregnant in summer, give birth to baby in advance of several rates be lowest.