Twin births are the exception, but they are on the increase. Some parents-to-be are happy because they want it to happen. Today we know more about the conditions that promote multiple births. This allows us to see clear connections between ethnic, anatomical and lifestyle facts and clustered multiple pregnancies.
In this article
There are identical and fraternal twins.
- Identical: originated from one egg, therefore identical genetic material, same sex, extreme similarity
- Fraternal: originate from two separate eggs, different genetic material, similarity like siblings
Prenatal determination of the presence of identical or fraternal twins is difficult. Fraternal twins always have their own amniotic sac or placenta, but this is sometimes not detected in ultrasounds. Identical babies either each have their own amniotic sac or share one, the placenta is the same. The probability of having twins that are fraternal is about twice as high as that of having identical twins.
Twins – a look at the statistics
It is noticeable that multiple births have been increasing in Germany since the mid-1990s. According to the website twinsworld, the German Federal Statistical Office recorded.de for 1952 per 1000 births 23.2 multiple children. In 1977 the probability of having twins was respectively. for a multiple birth at less than 1.8 percent. Since then, the probability curve has risen steadily again. In 2004, there was an all-time high of over 3.5 percent. This was achieved again in 2012 and surpassed again in 2015 with 3.75. This shows that statistics today give us a more accurate picture than earlier "rules of thumb" such as those of HELLIN, who predicted twin births at 1.14 percent.
As we will see later, increasing age of the woman at conception is conducive to multiple births. This has to do with the hormonal situation. The average age for a first pregnancy has also increased in Germany and explains an increasing multiple birth rate. Of course, the frequency of multiple births also reflects the increasing use of reproductive medicine: the usual implantation of several fertilized eggs increases the chance of pregnancy, but at the same time also the probability of multiple births.
Twin pregnancies also follow genetics
Hereditary factors favor a twin or multiple birth, as do life circumstances. If the mother is a twin herself and there are other twins in the family, then the chance of a twin birth quadruples. There are startling examples of this:
- A 26-year-old woman from Israel has twins of her own. She had fraternal twins three times in four years. And that without hormone treatment or other reproductive medicine.
- In the state of Utah, USA, two siblings made the headlines: Both are identical twins and both had twins twice each. However, both were also artificially inseminated, which has an additional favoring effect.
In the genetic characteristics for favoring a twin birth, only the woman’s genetic makeup is decisive. Whether a father who begets is a twin or has twins in the family is completely irrelevant.
What other conditions favor twin births
In addition to genetics, u.a. Ethnic origin, anatomy, nutrition and lifestyle habits decisive for twin births. African mothers have high twin birth rates, followed by Europeans. Low twin birth rates are seen in Asian and Hispanic women. If there have already been pregnancies, the chance of developing twins increases. It seems like when the body signals that the mother is robust and capable of carrying multiples to term successfully. This is also true for women who are tall, strongly built and well nourished.
The same applies to increasing age of women: although the chances of pregnancy are decreasing, twin pregnancies are becoming more frequent. From the age of 40, the probability of having twins increases from 3 percent to 7 percent, at the age of 45 even to 17 percent.
How to help the double happiness
There can be reasons for couples to wish a twin pregnancy. From the aforementioned favoring factors, a few recommendations can be derived on how a mother can significantly increase the chances of a twin pregnancy from the normal rate of about 3 percent.
- Take vitamins, especially folic acid supplements, maximum 1000 mg per day
- Ensure good nutritional status
- Consume a lot of dairy products and cassava (sweet potatoes)
- Take clomiphene (prescription), increases the chance of having twins to 33%
- Resort to in vitro fertilization, i.e. artificial insemination, increases probability to 20% and 40%
A consultation with an appropriately trained specialist is therefore always sensible and expedient for this topic.