Pregnant with twins - did you know these facts?

1. 1–3 % of all babies born are twins.
Twin births increased at the end of the 1900s. This can be explained partly by the amount of IVF treatments with more than one egg.

2. Around a third of all twins born are identical twins.
That means fraternal twins are twice as likely.

3. Identical twins always have the same biological sex.
That's because identical twins have the same DNA. In fraternal twins it's about 50/50: half have the same biological sex and half have different biological sexes.

4. After 30 there's a greater likelihood of getting pregnant with twins.
This is because it's more common that two eggs are released at ovulation when women get older.

5. Fraternal twins are no more alike than siblings.
Fraternal twins come from two different eggs that have each been fertilized by their respective sperm. They have different DNA and aren't genetically alike.

6. 40% of all twins are born vaginally around the world.
Twin 1 who is closest to the birth canal needs to be lying head down for a vaginal birth to take place.

7. It can be difficult to assess whether twins are fraternal or identical.
It can be detected during an early ultrasound scan or at birth, but the surest way to get an answer is to do a DNA test.

8. Around half of all twin births, happen before week 36.
If twins are born prematurely a Caesarean is usually performed and the babies may need to stay in a neonatal uni at first.