Question: Why does it take 9 months for a baby to grow in the mothers womb? why cant it be any

Darren Logan answered on 9 Mar 2012:

There is a huge range of times (called “gestational length”) that mammals spend in their mother’s womb before being born. Among the shortest is the Virginia opossum (about 14 days) and the longest is the elephant (over 600 days).

We don’t know for sure all the reasons for the differences, but there are a few things that seem to be involved. In general the larger the animal is, the longer is seems to take. This could be simply because it takes longer to grow a large animal from the egg and sperm.

However, a better indicator is brain size. The bigger your brain is at birth, the longer you need to be in the womb. This is probably because you really need the womb’s protected environment for your brain to develop properly. We know this because if you are born too early, there is a risk of brain damage.

So I guess the answer is that it takes 9 months for us to grow our large and well developed brains.