The time for pregnancy can vary between individuals, sometimes quite sharply for certain cases. The average time for human gestation is 9 months, so that is 9 x 4 = 36 weeks.
Although the average number of weeks per month (if you average it out over a year) is 4.33 weeks per month, so human gestation is closer to 39 weeks.
A pregnancy usually lasts about 40 weeks but you could go up to 42 weeks.
9 months 40 weeks
2 weeks or after
9 weeks on average.
9 Weeks
2 weeks
40 weeks
9 weeks on average.
around 9 weeks
Anna is 38 weeks Michelle is about 20 weeks
See the related link. About 9 weeks.
Pregnancy in ferrets lasts 38-42 days or 6 weeks