Normally the delivery date is calculated by adding nine months and seven days to the first day of the last menstrual period. This rule holds good for regular periods only. In cases where the periods are irregular or the date of the last period is unknown, an early ultrasound done in the first few months, can give a reliable guide to the delivery date. When the duration of pregnancy extends two weeks beyond the delivery date it is labeled as post term.

Reasons:
Post term pregnancy may be seen in 3-10% of normal pregnancies. Before a diagnosis is made, the dates need to be checked and confirmed. It is seen more in women pregnant for the first time and in those with previous post term pregnancies.

Symptoms:
Mothers and relatives are generally found to be quite anxious in post term pregnancies. The worries are of placental insufficiency and decreased water around the baby in the womb. While the former could lead to decreased supplies from the mother, the later may lead to choking in the womb.

Precautions:
Regular visits to the doctor especially near the time of delivery can help in preventing complications due to post dates.

General Treatment:
If there are no signs of compromise in the baby as assessed by ultrasound the options need to be discussed. Waiting may allow labor to set in on its own. If this does not happen or signs of compromise in the baby are seen, the patient needs to be hospitalized and medicines need to be administered to start labor pains.