Twin pregnancy

Dr. rer. nat. Daniela Oesterle is a molecular biologist, human geneticist and trained medical editor. As a freelance journalist, she writes texts on health topics for experts and laypeople and edits specialist scientific articles by doctors in German and English. She is responsible for the publication of certified advanced training courses for medical professionals for a renowned publishing house.

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They have twins! Many parents receive the news of a twin pregnancy with mixed feelings. The joy of double growth is usually great, but what challenges do the parents expect? Read everything you need to know about twin pregnancy, identical and dizygotic twins, multiple births after artificial insemination and the many challenges posed by twins!

Probability of having twins, triplets, etc.

According to a statistical rule (according to Helling), one twin birth comes to 85 single births (1: 85). For triplets, the probability is reduced to 1: 7,255 and for quadruplets to about 1: 614,000.

But in the last twenty years the number of multiple births has increased significantly. In 2013, for example, every 29th birth was a multiple birth, in 2019 every 54th birth. The increase is presumably due to artificial insemination (in vitro fertilization, IVF), which more and more women with an unfulfilled desire to have children are undergoing.

How do you have twins?

Many couples often want more than just one child at a time. Then the question often arises whether there are factors that increase the likelihood of a twin pregnancy.

There actually are. For example, the greater the woman's age, the greater the likelihood of twin pregnancies. In addition, twins occur in families.

Even with artificial insemination (in vitro fertilization, IVF) - as mentioned above - twins or other multiples are more common. The woman is usually given hormones before artificial insemination to encourage the egg cells to mature. As a result, more than one egg cell often matures in a cycle. So hormone therapy leads to an increase in multiple births.

But there is no way to directly influence the chance of a twin pregnancy.

How do twins arise in the body?

Twins arise either from one and the same fertilized egg cell (monozygous or identical twins) or from two fertilized egg cells (dizygote or fraternal twins). For triplets, quadruplets, etc., combinations of monozygotic and dizygotic offspring are possible.

Identical twins

About a third of all twin pregnancies are identical twins. In the first three days after fertilization, the egg cell divides into two genetically identical embryonic structures. The genome of the twins is identical to this. As a result, identical twins are always of the same sex.

Dizygotic twins

Far more common than identical twins are dizygoti twins. Two mature egg cells are fertilized in the same cycle. The fertilization by the sperm cells can happen at different times, since the fertile time of the woman extends over several days. The genetic makeup of the two egg cells is therefore different and usually differs just as much from one another as that of all other siblings. Dizygoti twins can therefore be of the same sex or of different sex.

Challenge for parents

Two (or more) children at the same time - this presents parents with a number of new challenges. If a woman is pregnant with twins, she has to carry significantly more weight than with only one child in her stomach. Joint and back pain are therefore not uncommon during a twin pregnancy. Nausea, constipation and water retention in the body are also more common than in single pregnancies.

More children mean more and more financial expenses. You should therefore find out in good time about state benefits such as maternity or parental allowance and possibly social assistance before you have the twins (triplets, etc.).

Last but not least, having more children always means more work and stress on the nerves. Therefore, at the beginning of the twin pregnancy, discuss with relatives, friends or acquaintances whether they can support you in times of high stress - be it with shopping, with housework or when it comes to a free evening for you.

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