In twenty years the number of twin pregnancies has practically doubled, reaching 25% of all pregnancies.
Among the causes of this increase certainly maternal age, which is increasingly advanced (as we get older, hormonal changes make it more likely the release of more oocytes that can be fertilized), and the increasing use of assisted fertilization which in fact increases significantly. the odds of having twins.
What are the numbers of twin pregnancies?
THEincidence of a "spontaneous" twin pregnancy, ie without having recourse to hormonal treatments or assisted fertilization, is 1 in 80 births for twins, and 1 in 8.000 births for triplets, while for quadruplets births there is one case every 730.000 births.
In case of treatment for the fertility what are the chances of a twin pregnancy?
Undoubtedly one of the main factors that favor multiple pregnancy is the use of assisted fertilization techniques but a lot depends on the type of treatment.
Also read: 10 tips for mom of twins
Here are the most relevant data
- I drugs that stimulate the ovaries increase the risk of more eggs being released.
- In case of in vitro fertilization the odds of having twins are between 20 and 40 percent, depending on how many embryos are implanted.
- THEintrauterine insemination in itself it is the only fertility treatment that does not increase the chances of a twin pregnancy. But most women who undergo fertility treatments take ovarian stimulation drugs.
What are the other factors that favor a twin pregnancy?
The pregnancy of homozygous twins (i.e. identical, born from a single egg fertilized by a single spermatozoon that has split into two parts, giving rise to two fetuses of the same sex) are pure chance, but there are some factors that can increase the chances of having twins heterozygous (two eggs conceived from two spermatozoa, therefore not identical).
Let's see what they are.
- Inheritance: if there are twins in the family, there is a greater chance of having twins. Furthermore, the probability that a monozygotic twin will have twin children in turn is high: 25% of the possibilities or 1 every 4 pregnancies generated.
- Age: The older you are, the more likely you are to have twins. women over 35 produce more follicle-stimulating hormone (FSH) which can cause more than one egg to be released per cycle. This means that women over 35 are less likely to get pregnant but more likely to have twins.
- Previous twin pregnancies: if you have had twins, the risk that future pregnancies will also be twins is twice as high
Number of pregnancies: Women who have already had children are more likely to have twins