Overdue baby - What to expect

Medically reviewed by

24th Feb 2023

Although pregnancy is described as 40 weeks in length it’s perfectly normal for a baby to be born anytime between 37 and 42 weeks.

When is a baby overdue?

Once a pregnancy reaches 42 weeks the baby is considered to be officially late or ‘post-term’.

If your baby hasn’t arrived by your due date it’s natural to feel disappointed – after all you have been waiting for nine months to meet your little one. Try not to be too down hearted though as one thing is for sure, your baby will be arriving within the next few weeks.

What causes a baby to be born later?

The exact reason as to why a baby is overdue is generally unknown however, it can be hereditory. Also, for women who have already had an overdue baby previously, it is more common for their next baby to also be a little late.

What happens if my baby hasn’t arrived by my due date?

If there is no sign of labour starting your midwife is likely to offer you a simple procedure called a ‘membrane sweep’ at your next antenatal appointment. This is usually at 41 weeks. She will explain what this involves and you can then decide whether to go ahead and have it done or whether you want to wait for labour to start naturally. After a membrane sweep labour often starts within 48 hours. If labour doesn’t begin, your midwife may suggest repeating the procedure or she may talk to you about having your labour induced between 41 and 42 weeks.

Induction is always planned in advance so you will have the opportunity to discuss the advantages and disadvantages as well as the form of induction that will be used, before you have to decide whether to go ahead.

How will being overdue affect my baby? Are there any risks of being overdue?

Many babies are born perfectly healthy at 42 weeks and beyond. However, there is evidence that if a pregnancy goes beyond 42 weeks the risk of complications for both mother and baby increases, which may include stillbirth. Induction is offered to all women who are still pregnant at 42 weeks.

What happens at 42 weeks if my baby is overdue?

In the unlikely event that your overdue baby hasn’t arrived by the time you are 42 weeks pregnant and if you still don’t want to opt for induction, then you will be offered frequent monitoring to make sure that your baby is healthy. This will be done at the hospital. You will be offered an ultrasound scan to monitor your baby and to check on the levels of amniotic fluid. If there are any concerns about your health or the health of your baby, your midwife or doctor will discuss this with you and suggest that labour is induced.