Postdates basics

Most pregnancies last between 37 and 42 weeks. When a pregnancy goes into the later part of this range (beyond 40 weeks), it is called postdates. When it goes beyond 42 weeks, it is called postterm or prolonged.

In order to support your informed choice discussion with your midwife, this website uses visual tools to explain important concepts related to postdates pregnancy. Having a clear understanding of these ideas may help you to make informed decisions.

What's in a due date?

To make decisions about postdates pregnancy, it may be helpful to understand the science behind due dates and the start of labour. Every woman is different, so the estimated due date is really just a guess. Researchers are still trying to learn exactly what happens in the body during pregnancy, how labour begins naturally, and what factors might affect its timing.

Explain the science of postdates pregnancy.
What are the risks?

Although most postdates pregnancies result in normal births and healthy babies, some risks are statistically higher in postdates pregnancies than in those lasting less than 40 weeks. You may want to find out what problems may occur and how often they happen in pregnancies that continue past 40, 41, or 42 weeks.

Tell me more about the risks.
What are my options?

If your pregnancy continues beyond 40 weeks, you may feel impatient, uncomfortable, and anxious to know that your baby is all right. There are different ways to address these feelings. Whatever you decide, it’s important that you talk with your midwife about your concerns and understand the risks and benefits of each option.

Break down the options for me.
Explain the science of
postdates pregnancy.
Tell me more about
the risks.
Break down the options
for me.