It is fairly common for babies to be two weeks overdue. About 15 per cent of pregnancies reach 42 weeks. There is, however, no reason to assume that your second baby will be late. Labour usually happens when the time is right. Unless there is any suggestion that the baby is compromised in any way there is no reason why nature should be interfered with. No one really knows what causes a baby to be overdue. It is true that some women seem to always deliver after their due date, whereas others have shorter pregnancies. The estimated date of delivery is just that, and the normal length of pregnancy in some women seems to be slightly longer than in others.