How does a pregnancy work and what is a premature birth?

If a planned pregnancy is announced, the joy of the parents is especially great! The weeks before the baby is born are an exciting but also worrying time for the parents-to-be.

It is a time between anticipation and worry about the health of the unborn child. But what exactly happens in the mother's body during a pregnancy and what stages of development does the baby go through in the weeks leading up to a pregnancy?

Everything begins with a positive pregnancy test, doesn't it? Normally, a scheduled pregnancy lasts between 38 and 41 weeks. This is the period from the last menstrual period until the birth. This means that a woman is not really pregnant in the first weeks of pregnancy.

About 14 days after the last menstrual period, ovulation takes place. New life is created when one of 500 million sperm successfully makes its way to the egg cell and fertilises it. In the next step, the egg makes its way into the uterus and nests there. Shortly afterwards, a pregnancy can already be determined with a test.

The weeks of pregnancy can be divided into three trimesters of varying duration.

The first trimester contains the first 12 weeks of pregnancy and is also the most critical phase. During this time the probability of miscarriage is the highest at 20%. At the end of this trimester, all the baby's organs are already attached and the baby can be recognised as a small human being. It is often the case that the mother feels particularly unwell during this phase, as the body reacts to the altered hormone levels. In most cases, this discomfort subsides in the second trimester of pregnancy.

The second trimester includes the 13th to 24th week of pregnancy. During this time the baby grows significantly. From the 20th week of pregnancy the mother can feel her baby for the first time.

The last and also longest trimester includes the 25th to 40th week of pregnancy. At the end of the pregnancy the baby gains weight again. In addition, the development of the organs and brain is completed. The majority of births take place in the two weeks before and after the calculated date of birth.

One speaks of a premature birth if the child is born before the completion of the 37th week of pregnancy or weighs less than 2,500g at birth. The baby is then also called "premature".
Babies that are born before the 29th week of pregnancy or weigh less than 1,500g are considered risk patients and must be treated in special clinics, so-called perinatal centres for intensive care.

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