One in every eighty pregnancies results in twins so you are far from being alone if you've just received the news that your bump contains two little bundles of joy.

The knowledge that you are expecting twins (or a multiple birth) can result in a whirlwind of emotions. One moment you'll be on top of the world, grinning from ear to ear. The next you'll be weepy, full of worry and anxiety. And all at a time when your hormones are all over the place anyway. Some of you may feel that this is the worse possible thing that could have happened to you. These thoughts and emotions are all perfectly normal and as the news sinks in, you'll soon get back on an even keel again.

Twins can be identical (from one fertilised egg that splits) or non-identical (from two separate eggs). Identical twins are the same sex as they have the same genes. Non-identical twins can be the same sex or one of each. In the UK, two thirds of all twins are non-identical and one third are identical.

You are more likely to have non identical twins if:
* You've undergone fertility treatments
* Have other sets of twins in your family (especially if there's non identical twins in your mothers family)
* The chance of twins increases if you're over the age of 30 and have been pregnant before (especially if you've already had a multiple pregnancy)
* Women with a Body Mass Index (BMI) of 30 or higher have an increase in chances of having twins. Taller women are also more likely to have twins.
* Some ethnic groups have a higher proportion of twins than others – this is because the tendency to release more than one egg at ovulation may be inherited. Women from African ethnic groups are more likely to have non-identical twins than white women, and women from Asian ethnic groups are less likely to have non-identical twins

Identical twins seem to be simply random by nature. However there does seem to be an increased chance in families who already have identical twins. It has also been suggested that the eggs in older women are more brittle, hence more inclined to split, resulting in identical twins.

How can I increase the chances of having twins? more

How do I know I am carrying twins? more

How does a twin pregnancy differ from a single pregnancy? more
Antenatal care in twin pregnancy
Complications of twin pregnancies for babies
Complications of twin pregnancies for mums

How does the labour and birth differ in a twin pregnancy? more