What is the chance of having twins?

When a woman has a very big belly in the early stages of her pregnancy, people often immediately assume twins. The chance of having twins is always present. But how big is the chance? The chance of having twins is about 1 in every 80 pregnancies.  

 


Does the chance of having twins increase as you age?

The chance of having twins indeed increases as you age. Research shows that women older than 35 are 3x more likely to have twins than women who are 20 years old.

What other factors increase the likelihood of twins?

Besides age there are a few other factors that increase the chance of having twins:

- If the mother is of African descent
- If the mother is heavier than average
- If the mother gave birth to a child in the past

Is there an increase in twins being born?

The number of twins being born is strongly increasing. This is partially due to that women are having children at an older age, and that more and more women are undergoing fertility treatment. A fertility treatment has a lot of influence on the chance of having twins. Thus the chance of having twins is strongly increasing. 

What is the chance of having triplets or quads?

Besides having twins, there is of course also the chance of having triplets or even quads! However, the chance of this is considerably smaller. In the UK about 170 triplets are born each year, but only about 3 pregnancies have quads, or more.

Without fertility treatment the chance of a multiple pregnancy is:
Triplets:   1 in 6.400 pregnancies
Quads:    1 in 512.000 pregnancies
Quints:    1 in 40.960.000 pregnancies

What is the average duration of pregnancy with twins?

The average duration of pregnancy is often shorter with twins than with one child. With twins the average duration of pregnancy is 37 weeks instead of 40 weeks.

 

See besides chance of having twins also:
Average Number of Children 
Average time to get pregnant