how long do pregnant?
40 weeks is about 9 months and 1 week (9.2 months). Actual gestation (from conception to birth) is just under 9 months. Whether or not a baby is premature depends more on its size and weight than how many weeks along the mother is in the pregnancy. When referring to length of pregnancy, if a baby comes early (generally before about 36 weeks) it is best referred to as pre-term. This means that a baby could be pre-term but not premature.