Synonyms in a broader sense
Gestation, Gravidity
How long does a pregnancy last?
The duration of a pregnancy is usually counted from the first day of the last normal menstrual bleeding, because the exact time of fertilization – i.e. when sperm and egg fuse together – often cannot be determined exactly. If a pregnancy is counted from the day of fertilization or conception, this is called post conceptionem (p. c) in Latin. It usually takes 40 weeks from the first day of the last menstrual bleeding until birth.
The pregnancy is divided into three thirds of pregnancy, also called trimesters. The actual duration of pregnancy is usually given in number of pregnancy weeks and days. For example, if the duration of pregnancy is given as 22+4, the expectant mother is 22 weeks and four days pregnant and is therefore in her 23rd week of pregnancy (the sixth month of pregnancy and the second trimester).
- The first trimester of pregnancy comprises the first to third month of pregnancy or the first to twelfth week of pregnancy (SSW).
- The second trimester describes the fourth to sixth month of pregnancy or the 13th to 28th week of pregnancy.
- The third trimester of pregnancy comprises the seventh to ninth month of pregnancy or the 29th to 40th week of pregnancy.
The first third (trimester) of pregnancy is the most rapid and at the same time the most sensitive period of development to harmful influences (such as smoking during pregnancy). It is during this phase that most of the terminations (abortion/loss of the fruit) occur. Due to the intensive hormonal changes in women, 3/4 of pregnant women in early pregnancy experience severe nausea.
In the course of the pregnancy spot-like pigmentation (chloasma) may develop on the face. After the first weeks of pregnancy, many women also complain of increasing sensitivity and tension in the breasts. 1st month: In the first month of pregnancy, fertilization and implantation take place.
The placenta enables the exchange of substances between the maternal and fetal circulation and supplies the embryo with oxygen, nutrients and antibodies. More information about the first month is available from our partner. 2nd month: These weeks are characterized by rapid growth of the embryo: While the crown-rump length (SSL) in the 7th week is still 4-8 mm, in the 8th week it is already 9-15 mm.
The hormone-dependent (especially hCG) morning nausea, vomiting, mood swings and ravenous hunger attacks begin to come to the fore. The erection of the uterus causes a stretching of the uterine ligaments, which can lead to pulling pain in the groin area. The placenta enables the exchange of substances between maternal and fetal circulation and supplies the embryo with oxygen, nutrients and antibodies.
More about the first month with our partner 2nd month: These weeks are characterized by rapid growth of the embryo: While the crown-rump length (SSL) in the 7th week is still 4-8 mm, in the 8th week it is already 9-15 mm. The hormone-dependent (especially hCG) morning nausea, vomiting, mood swings and ravenous hunger attacks begin to come to the fore. The erection of the uterus causes a stretching of the uterine ligaments, which can lead to pulling pain in the groin area.
The amniotic fluid that surrounds the embryo/fetus and shields it from external influences such as vibrations and temperature fluctuations, and large organs begin to form. In the 6th week, the formation of the spinal column and the closure of the neural tube is observed, from which the brain and spinal cord later emerge. Week 7 includes the formation of buds from which limbs develop.
Now the first heart actions are also detectable in ultrasound. Fingers, facial features and gradually all organs develop in week 8. The heart rate of the embryo is now around 140-150 beats per minute (bpm).
3rd month: Around the 10th week, all organs are already created. The cartilaginous ear, nose and toes begin to develop. The attachment of the milk teeth develops and the embryo is able to make its first movements.
The changes in the pregnant woman’s body take place during this phase, especially in the cardiovascular system: The maternal blood volume increases by an average of 1.5 L in order to be able to supply the embryo sufficiently. This also results in an increased pulse rate in the pregnant woman. In addition, hormone-dependent vasodilatation leads to a tendency to bleed on the mucous membranes of the nose and mouth as well as varicose veins and spider veins.The increased urge to urinate in this phase can be explained by the progesterone induced reduced tone of the sphincter muscles.
Oestrogen-dependent water retention in the tissue can lead to weight gain. At the end of the 3rd month, the average embryonic weight is 14g with a length of 3.5 to 5.5 cm. In the 10th week of pregnancy, the transition from embryonic to foetal period takes place.
The second trimester is characterized by increasing satisfaction on the part of the pregnant woman: The complaints caused by the hormonal changes (nausea etc.) decrease, the pregnancy is much less threatened by abortion and the first foetal movements are noticeable for the mother. 4th month: The hormone production of the ovary is now taken over by the placenta.
As a result, the hormone level is somewhat lower, which can alleviate the previous, hormone-related complaints. The pregnant woman now gains half a pound per week on average. This can cause the first stretch marks on the skin.
The more heavily pigmented line that extends vertically from the navel to the pubic bone (Linea nigra) is hormone-dependent and usually recedes after pregnancy. In the fetus, the genitals may become visible in the ultrasound. The eyelids now begin to close and a fluff forms on the skin – lanugo hair.
The placenta takes over the detoxifying function of the liver, which in contrast to the kidneys, stomach, intestines and lungs is not yet working. These organs are trained by swallowing and excreting amniotic fluid, which is renewed approximately every 11 hours. The foetal size is about 10 cm, the weight is about 100 g. 5th month: In pregnant women, magnesium deficiency can cause calf cramps.
The foetal weight is 200 to 300 g and the crown-rump length is about 15 cm. 6th month: The uterus can cause some discomfort due to its increasing size (its upper edge is now approximately at navel level): Pressure on the stomach and bladder can cause heartburn or increased urination. In addition, the breasts swell up depending on the hormones.
From this month on, the child begins to react to visual and acoustic stimuli from outside. Cheese smear (Vernix caseosa) develops on the skin, a layer of fat that protects the infant’s skin from the amniotic fluid and makes it easier for it to slide in the birth canal during birth. The fetus now weighs about 500g and is about 26 cm long.
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