Chance of Having Twins Again: Who’ll Have a Second Set?
You might be thinking about the chance of having twins again if you have one set of twins already.
The idea of having twins tends to fascinate people. Some people would love to increase the chance of parenting two babies at the same time, and others react in an entirely different way. Life with twins can be busy and chaotic, but some parents dream of having more children after having twins. Experience single child moments, breastfeeding without having another child crying, or you just want a big family. But what is the chance of having twins again?
Identical or non-identical twins
First we need to understand the two types of twins; identical and non-identical. Identical or monozygotic twins are formed when one egg is fertilized by one sperm cell, which then divides into two separate embryos. Each shares the same genetic components and identical genetic structures. With non-identical twins, it works slightly differently. They form from two separate eggs being fertilized by two separate sperm cells. These twins share no more genetic composition than siblings with the same parents. Some women are genetically more likely to get pregnant with twins. However, there are several factors that increase the chance of becoming
pregnant with twins.
Genetic influences & chance of having twins again
It is a well-known fact that more non-identical twins occur in some families than others. If someone blood related in your family was or had non-identical twins, you might have inherited a gene for hyper ovulation, increasing your chances of conceiving twins. The genetic predisposition for having twins only applies to the mother, but fathers can carry the gene and pass it on to their daughters. So far researchers haven’t been able to find a genetic link in identical twin pregnancies.
Maternal age and previous pregnancies
Several studies have shown that women in their mid- to late thirties are more likely to conceive twins than younger women. Furthermore, research also shows that the chance of having twins increases with the number of times a woman has given birth.
Geographic & chance of having twins again
The chance of getting pregnant with twins, varies enormously from one country to the next. African women are more likely to have twins. The rate of identical twins is the same the world over, but rates of non-identical twins vary – the highest being in Nigeria and the lowest in Japan.
Body length & weight
Fraternal twins are slightly more common in taller or heavier women than they are in small women. The reasons for this are not clear.
Infertility treatment plays a significant part in the increase of fraternal twin births in the past decades.