Synonyms in a broader sense
Pregnancy is defined as the phase lasting on average 267 days (p. c. , see below) during which a fertilised egg cell matures in the female body. The progression of the pregnancy is expressed as weeks p. m. (post menstruationem, after the last menstruation), since this is known to the woman with greater certainty than conception (p. c. , post conceptionem). This means that the actual foetal or embryonic age is 2 weeks less.
In the following, the information will always refer to the age after the last menstruation. With regard to childbirth, one also speaks of the pre-, peri- and postnatal phase, which refers to the period before, during and after birth. The 9 months of pregnancy are further divided into 3 periods of 3 months each (trimester, trimester).
Up to the 10th week of pregnancy, the fruit is referred to as an embryo, then as a foetus. Within the female menstrual cycle, ovulation occurs on the 15th day after the start of menstruation. The ovulation product, the egg cell, measures about 0.2 mm and after ovulation remains in the fallopian tube (tube), where it remains fertile for 12 to max.
24 hours. Fertilisation takes place when, after ejaculation, usually a single sperm cell (sperm – capable of fertilising for a maximum of 2-3 days) penetrates the egg (in the case of fraternal twins / triplets, this is equivalent to 2 or 3). Now the 2nd maturation division takes place with loss of one polar corpuscle (impregnation).
The simple chromosome sets of sperm and egg fuse (conjugation) and a cell capable of development (zygote) is formed. Within about 3 days, this cell migrates through the fallopian tube under hormonal control by means of flickering, tube secretion and motility and undergoes cell division into a morula (Latin mulberry, eight-cell stage). On the 4th to 5th day the transfer into the uterine cavity (cavum uteri) takes place.
Further cell division takes place to form a blastocyst, which usually implants itself in the posterior wall of the uterus around the 6th day after ovulation. This process takes 14 days and twinning is still possible until it is completed. The blastocyst splits into 2 layers: The outer layer (trophoblast) from which the placenta is formed and the inner layer (embryoblast) from which the embryo is formed.
These two layers are connected by the umbilical cord. About 24 hours after fertilisation, precursor cells of the placenta (syncythiotrophoblasts) produce the pregnancy hormone hCG (human chorionic gonadotropin). This stimulates the corpus luteum in the ovary to produce progesterone, a hormone that suppresses further ovulation and menstruation.
In addition, these hormones loosen the lining of the uterus, which will also facilitate implantation. Many women notice the first signs of pregnancy even before the first menstrual period is over: breast tenderness, increased urge to urinate, nausea and discomfort in the abdominal area can be such signs (pregnancy symptoms). Some also observe abnormal eating habits and circulatory problems.
From a scientific point of view, the indications (indicators) of pregnancy are classified as uncertain, probable and safe, depending on their reliability. Uncertain indicators are the absence of menstruation, morning vomiting and nausea as well as gynaecological changes (livid discolouration of the vagina, uterine enlargement). A likely indicator of pregnancy is the positive result of a pregnancy test (e.g. Clearblue®), which takes advantage of the increase in the concentration of the pregnancy hormone hCG in urine or blood.
A reliable indicator is the definitive detection of an embryo/fetus by ultrasound, fetal heart sounds and fetal movements. During pregnancy many women show typical signs of pregnancy. These include complaints of the gastrointestinal system, such as flatulence, heartburn or nausea, but also gynaecological symptoms in the form of pulling in the breast and, of course, the absence of monthly menstruation.
Especially during early pregnancy, many women complain of frequent flatulence. This can be explained by an increase in the progesterone level (progesterone is one of the corpus luteum hormones responsible for maintaining pregnancy), which relaxes the visceral muscles. This also relaxes the muscles of the gastrointestinal tract and digestion is then much slower.
In this way, the intestinal bacteria can produce much more digestive gases over a longer period of time and thus cause flatulence. Due to this effect of progesterone, many women also notice frequent heartburn during early pregnancy. The lower closure mechanism of the oesophagus, which normally prevents gastric acid from rising from the stomach into the oesophagus, is relaxed by the increased progesterone level and thus facilitates the passage of gastric acid.
However, heartburn is also a major burden in the last trimester of pregnancy. It is not so much the hormones that are important for the development of heartburn, but rather the stomach acid, which is pushed up from the stomach into the oesophagus by the growing baby and thus causes the typical heartburn (usually manifests itself in the form of burning pain behind the breastbone). It is therefore a symptom that can occur in any part of the pregnancy.
Another common sign of pregnancy is pulling in the breast or breasts. Around the 5th to 9th week of pregnancy, the body begins to prepare the mammary gland tissue for a possible breastfeeding period after delivery, and many women notice a tightening and an increase in the size of their breasts. Some women even feel a pulling pain as well as an extreme sensitivity to touch of their breasts.
The colour of the nipples can also darken during pregnancy. Another fairly certain sign of pregnancy is the absence of periods. However, it must be said that the absence of menstruation can also have other causes than an existing pregnancy.
Nevertheless, for most couples it is the first sign of pregnancy. This sign can be detected very early on, usually in the second or third week of pregnancy, during which time the pregnancy is often not even confirmed by a gynaecologist, but continues until delivery. All these signs of pregnancy are typical symptoms that are present in the majority of pregnant women. However, their occurrence is by no means sufficient proof of an intact pregnancy.