Pregnancy is the carrying of one or more embryos or fetuses by female mammals, including humans, inside their bodies.
In a pregnancy, there can be multiple gestations (for example, in the case of twins, or triplets).
Human pregnancy is the most studied of all mammalian pregnancies.
Human pregnancy lasts approximately 9 months between the time of the last menstrual cycle and childbirth (38 weeks from fertilisation).
A pregnancy is considered to have reached term between 37 and 43 weeks from the beginning of the last menstruation.
Babies born before the 37 week mark are considered premature, while babies born after the 43 week mark are considered post-mature.
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