If your pregnancy is healthy it is important you wait for nature to come when it want. If you are trying to force labor you should wait at least 39 weeks. Pregnancy usually lasts 40 weeks as opposed to the nine months that are typically touted. In order to give the mom and baby time you need to wait 39 weeks. Important organs might need extra time to develop. Babies might also gain extra weight which will help them stay warm.

Read more: Why is 39 weeks so important?