Chances of having twins and 5 tips to boost your odds
The thought of having twins is a dream to some – to others too much of a good thing. If you belong to the first category and love the idea of having two toddlers, you should read along. We have gathered a list of things which might influence the chances of having twin babies.
Double trouble or double joy? While some people fear that the ultrasound will reveal two heartbeats, others actively try to increase the odds of having two babies at once. But what are the actual chances of having twins, and what determines these chances?
You may have heard that having twins can run in the family, or that having fertility treatment increases the chances of a twin pregnancy. But there is far more to it than that. Age, BMI, genetics, and fertility treatment are all factors, that might affect your chances of having twins. Below, we take a closer look at each of these factors. To fully understand these, however, we will start by explaining the two different types of twins and the likelihood of becoming a twin parent.
The difference between fraternal and identical twins
There are two types of twins: fraternal and identical. Fraternal twins are a result of the woman developing two or more eggs which then are fertilized by different sperm cells. Because the two different eggs are fertilized with different sperm cells, the fraternal twins do not share the same DNA. This is not the case with identical twins, where one egg is fertilized and then develops into two or more embryos. Because one egg is fertilized with one sperm cell, the identical twins will share the same DNA.
While becoming pregnant with fraternal twins can be dependent on the factors mentioned, having identical twins is coincidental. This means that it can happen to any woman.
But what are the chances of having twins?
Accordion to a study from The Tech Interactive. In 4 out of every 1000 births in the UK resulted in parents having twins. However there are differences in having twins depending on whether they are fraternal or identical twins.
Chances of having fraternal twins
The chances of having fraternal twins happens once a time in every 250th natural birth.
Chances of having identical twins
The chances of having identical twins are a bit more rare, with an identical twin birth happens once in every 333 birth. The chances of two embryos developing from one egg is rarer than two eggs being fertilized. Below we look into some of the factors that increase the chances of having twins.
Fertility treatment can lead to a twin pregnancy if more than one embryo is transferred to the uterus during IVF treatment.
If the woman is over 35 years old
Age influences your chances of becoming pregnant with fraternal (non-identical) twins. Studies show that it is more common for women over 35 years of age than for younger women to have twins. This is due to an increased production of the hormone FSH which may lead to the release of multiple eggs.
If you want to learn more about ovulation follow the link to read our blog post.
A high BMI can increase the chances of having twins
Having a BMI (Body Mass Index) over 30, which indicates that a person is overweight, has been linked to increased chances of having a twin pregnancy, according to previous studies.
However, having a BMI over 30 is not recommended, as this is not healthy, and might reduce your chances of achieving a pregnancy at all. In fact, some fertility clinics operate with a BMI limit and only perform fertility treatments on women with a BMI below 30 or 35.
Fraternal twins can be caused by hereditary factors, age and race, identical twins is coincidental.
Twins are more likely to have twins
The chances of a twin pregnancy can also depend on your genetics, since hyperovulation (the ability to conceive more than one egg) is hereditary. Hyperovulation is only hereditary from your mother´s genetics, not your father´s. This means that if your mother is a twin or you are a twin yourself, you have a higher chance of releasing more than one egg to be fertilized. This is also the case for sisters. If your sister has had a twin pregnancy, you are more than 2.5 times more likely to have twins yourself.
Please note that this hereditary factor only concerns fraternal twins. Identical twins are not affected by hereditary conditions.
Twins are more common after fertility treatment
Fertility treatment can boost the chances of having fraternal twins. If you take fertility drugs to stimulate the ovaries, for example before an IUI treatment, the chances of releasing more than one egg each month are higher. In some cases, IVF treatment can also lead to having twins, if more than one embryo is inserted into the uterus. Though, today it is most common for fertility clinics to insert only one embryo in an IVF treatment.
Usually, before fertility treatment the follicles are scanned to observer how they develop. During this scan, it is possible to see the number of eggs released. Therefore, if you want twins, you can choose to fertilize during a period where multiple eggs are released.
If you liked this post, you may also like this post about bodily changes during pregnancy.