Twin Birth: What is it? How and when are twins born?

twin is the way in which the birth of two or more children is carried out, at the end of a multiple (or plurifetal) pregnancy.

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Depending on the health conditions of the expectant mother and the twins, delivery can be performed naturally or by caesarean section.

Generally, vaginal birth is possible when the pregnancy has come to an end without major problems and the presentation of the first child is cephalic.

In the event that these conditions are not present or the twins are more than two, a caesarean delivery is scheduled.

routinely at the 18-20th week. As a rule, twin birth involves the birth of two babies. Cases of multiple births are, on the other hand, rarer.

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• Twins can be of two types:
  • Monozygotes (monovular twins): they are formed by the fertilization of a single oocyte by a single spermatozoon; before reaching the uterus, the product of conception separates into two or more independent parts, but each capable of giving rise to a complete individual. Monozygotic twins are so similar that, in general, it is difficult to distinguish them. Their genetic heritage is identical.The number of amnion and chorion depends on the moment in which the separation took place, therefore the pregnancy of monozygotic twins can be bicorical or monochorionic.
  • Dizygotes (biovular twins): occurs by fertilization of two oocytes, by two spermatozoa. In this case, the unborn children can look alike or be different, just like all the other brothers and sisters. The dizygotic twins develop in two distinct chorionic envelopes (bicorial twin pregnancy).

of the mother along the pelvis, as happens in a normal natural birth.

If the presentation is breech, the gynecologist looks for the feet and the baby is let out (note: before this maneuver the administration of oxytocin, the hormone that induces contractions, is suspended to leave the necessary space). normal breech, the second twin has less difficulty in being born, as the first twin has already "opened the way".

If the baby presents itself sideways, in an attempt to bring him into a position more favorable to twin birth, an obstetric turning and extraction maneuver is performed.

Sometimes, the expulsion of the second twin is difficult or impossible: in these cases it is necessary to resort to a caesarean section.