The fetus develops quickly during the first eight weeks of pregnancy. All the major organs and structures of the body are formed during this time. After this, the development will continue mainly as growth. From now on, the individual's susceptibility to various developmental disturbances and malformations decreases. This reduces the chance of miscarriage. Inside the uterus, the fetus moves in amniotic fluid, while the amniotic sac and the wall of the uterus provide it with protection.

The stages of fetal development.

After the fifth month of pregnancy, the fetus is approximately 30 centimeters long and weighs nearly 500 grams.

As the nervous system develops, the growing fetus begins to receive information from the outside world through various senses. For example, the sense of touch manifests itself in response to the mother’s movements. Similarly, thanks to the development of the sense of hearing, the mother’s voice becomes familiar to the child even before birth.

During the last months of pregnancy, a layer of fat forms under the skin of the fetus. This helps the fetus tolerate the lower temperature of its environment after birth.

At the beginning of the 35th week of pregnancy, the fetus is usually settled in the uterus so that it is ready to be born headfirst. If the fetus is in a different position, a caesarean section is often carried out.

A human pregnancy lasts for approximately nine months, or 40 weeks. During this time, the fetus grows to approximately 50 centimetres in length, and weighs about three kilograms. In a 38-week-old fetus, the individual's lungs are already developed so that no attempt is made to slow or prevent the course of labor if there are signs that it is starting.

Changes also occur in the mother's body during fetal development. Potential fatigue and nausea often pass after early pregnancy. Maternal weight increases slowly at first, but grows rapidly after mid-pregnancy, due to weight of the fetus, amniotic fluid and placenta, as well as an increase in blood and other body fluids. On average, a pregnant woman experiences a weight gain of approximately ten kilograms, about half of which is lost during childbirth. Pregnant women should regularly visit a clinic, where the well-being of both the mother and the fetus are monitored.

Fetal development can be examined via ultrasound imaging or by taking an amniotic fluid sample or a maternal blood sample. At the clinic, the weeks of pregnancy are calculated from the beginning of the last menstrual period. From there, embryonic and fetal development takes 40 weeks until birth. Because ovulation occurs about 14 days after the onset of menstrual bleeding, the actual duration of pregnancy is 38 weeks.