Could I be expecting twins?
You can’t help but be fascinated
with twins and you may wonder what your chances of having twins or multiples
might be.
The frequency of twin and multiple pregnancies has increased over the
last 30 years, probably due to more women undergoing IVF treatment and also because more women are delaying having
children until their thirties (your chance of conceiving twins increases with
age).
Identical twins
One third of all twins are
identical, or monozygotic – when the fertilized egg splits in two. They are
always the same sex and usually share a placenta. Identical twins appear to be
completely random and the chance of any woman having identical twins is one in
300.
Non-identical twins
Fraternal twins, or dizygotic,
occur when two eggs are released and fertilized by two separate sperm. Half of
fraternal twins are a boy-girl mix and half are the same sex. They have their
own placentas. Fraternal twins can run in families, inherited mostly on the mother’s
side. Age plays a role in the occurrence of twin pregnancies, because women over 35 have a higher chance of conceiving fraternal twins, with the
odds increasing to one in 27 if the woman is over 35. This is because the older
you get, the more likely you are to produce ovulation stimulation hormones that
make your ovaries produce more than one egg each month.
Fertility treatments
Fertility drugs and treatments can increase your chances of having
twins because they stimulate the ovaries into releasing more than one egg at a
time. These treatments are used for couples who need help to conceive and are
not available to everyone.
If you have any unanswered
questions, ask our resident gurgle experts by going to our answers page.
The information in this feature is intended for
educational purposes only. If you have any concerns about your health, the
health of your child or the health of someone you know, please consult with a
doctor or other healthcare professional.