Actually yes in reality a woman is pregnant with the baby for 10 months instead of only 9 months.
For most women they don't find out that they're pregnant with a baby until 6 weeks after conception so yes it does take at least 10 months for a full term baby to be born.
However the baby should not stay in any longer than needed because that too can cause problems and in some cases a C Section may need to be performed if the baby still hasn't come out naturally but the baby is full term.