If two eggs are provided when a woman ovulates and each is fertilized by a male sperm cell, two independent embryos are created in the womb, with different genetic information from the father and mother. For example, the first sperm cell and one egg could develop into a girl with dark hair. The second sperm cell with the other egg might produce a blond boy. Fraternal twins are therefore nothing more than siblings – with all the differences and similarities that characterize siblings. Only the dark-haired “big” sister is born a few minutes before her “little” blond brother.

The number of fraternal twins has been increasing recently. The reason for this is that more women than in the past are having hormone treatment for an unfulfilled desire to have children. In this procedure, several oocytes often originate from the ovary of the future mother. They are removed from her, fertilized in a test tube with the sperm of the future father and returned to the uterus. “Since up to three embryos are returned to the uterus, twins or even triplets often develop,” reports Berlin gynecologist Ulrike Schöneck.

Two From One Egg

When identical twins develop, a single egg from the mother is fertilized by a sperm cell from the father. Shortly thereafter, however, an extraordinary process begins: The fertilized egg divides into two halves. And within about 10 days, two embryos are created – identical twins: each of the two children carries the same genetic makeup of mother and father. Thus, for example, dark-haired sisters or two blond brothers would grow up in the womb.

Twin Pregnancy – A Risk?

Obstetricians generally classify a twin pregnancy as a high-risk pregnancy that must be conscientiously monitored. However, this should not unsettle expectant parents. After all, intensive medical support ensures that the pregnancy goes as smoothly as possible. Regular ultrasound examinations, for example, quickly reveal whether both twins are being adequately supplied by the placenta. “During the examination, special attention is also paid to growth disorders and prematurity,” says gynecologist Schöneck.

Two babies naturally need more space. As early as the 24th week, the two are “jostling” each other in the belly. After all, both together will soon weigh around three kilos – as much as a single baby at birth! From now on, the risk of premature birth increases. Sometimes one of the twins lies so awkwardly in the uterus that a Caesarean section cannot be avoided. However, if their position is correct, for example if the first child is in a cranial position, the mother can deliver both babies spontaneously.

Special Features Of A Twin Pregnancy

• Nausea: Many women experience severe vomiting in the first few weeks. This is due to the production of estrogen. It is twice as high in a mother with twins.
• Increased shortness of breath: This is caused by the larger abdomen and the greater burden on the woman. A mother of twins weighs 17 to 20 extra kilos at the end of her pregnancy. For a mother with one baby, it is eight to 13 kilos.
• Gastrointestinal problems: As the children get bigger, they press against the stomach and diaphragm. Many mothers with twins can therefore only eat small portions at the end of pregnancy. Heartburn and constipation are not uncommon. Recommended foods are whole grains and dairy products, vegetables, raw vegetables.
• Urinary urgency: The twins put increasing pressure on the bladder.
• Varicose veins, water retention (edema): These symptoms are also more pronounced in expectant mothers of twins. Support stockings and cold showers have a soothing effect.