Your due date only approximates the date on which you will deliver.
Only about two out of 10 women deliver in their 40th week of pregnancy.
About two out of 10 women will deliver after their 40th week and almost six out of 10 will deliver before.
Since one in eight women will deliver before reaching full-term (the 37th week), you should prepare for delivery well in advance of your due date.
Most doctors make sure their pregnant patients deliver before the end of their 42nd week because postdate pregnancies that extend beyond 42 weeks require special monitoring. Babies born after 42 weeks are more likely to have problems than those born at 40 weeks.