The birth canal summarizes all the female reproductive organs that the baby must pass through during its birth. It leaves the uterus through the open cervix during the pushing contractions and is pushed out of the mother’s body through the vagina. All of these organs are part of the human birth canal.
What is the birth canal?
In humans, an unborn baby lies deep in the mother’s pelvis, where it can develop well protected for 9 months. Unlike fish or frogs, for example, humans can thus give birth to only one child per birth, as it is much more likely to survive birth and the first critical months of life than a newly hatched fish, for example. The size of the human birth canal is therefore evolutionary, because as embedded in the body as the human baby is – it has to travel this distance at birth to leave the mother’s body. The birth canal includes not only the vagina and the cervix in a broader sense, but also the mother’s pelvis, as this can become one of the biggest hurdles for the unborn baby. The birth canal thus serves as protection for the unborn child during its development against harmful and life-threatening environmental influences of all kinds, as the mother can protect her child well as long as it is in her own body.
Anatomy and structure
In a strict sense, the birth canal in humans consists of the cervix and vagina. The cervix represents the entrance and exit of the uterus. During pregnancy, it is tightly closed and additionally protected by a protective mucus plug. This means that no fluid can escape and hardly any germs can penetrate upwards into the uterus, as they have to pass the cervix to do so. The cervix opens in the course of the birth and thus opens the way for the baby into the further birth canal. If this does not happen, a natural birth cannot take place. The vagina lies between the uterus and the outside world and also has a protective effect on the unborn child. Many pathogens already perish in the vagina because it has a slightly acidic environment and neither bacteria nor viruses can survive well in it. In a broader sense, the pelvis itself is also still part of the birth canal. The baby initially still lies in the mother’s pelvis before being pushed into the birth canal. Female pelvic bones are wider than male ones because a child’s head and body must fit through them. If the baby cannot pass through this part of the birth canal, a natural birth is impossible.
Function and tasks
The birth canal is especially important for the 9-month pregnancy, during which its components provide valuable protection for the unborn baby. Humans have only one child per birth only because they are capable of providing far better protection to a single offspring than other species. As a human baby develops, it lies safely and well protected “behind” the protective mechanisms of the birth canal. The acidic environment of the vaginal mucosa prevents germs from reaching him before his immune system is developed enough to cope with them. The cervix acts as an additional protection against disease. Moreover, since the unborn child is inside the mother’s body, in protecting herself from enemies she simultaneously protects herself and also protects her child as long as it has not yet made its way through the birth canal – at least that is the evolutionary thinking behind this reproductive strategy. When the child is finally viable after 9 months of pregnancy, every part of the birth canal enables it to be born. The pelvis is wide enough to allow the head and body to pass through. The cervix opens to give way to the outside. The vagina serves as the final channel through which the baby is pushed by labor.
Diseases
One of the most common complications involving the birth canal is pelvic bone. It is unalterably shaped in the adult woman, so the baby either fits through its shape – or, in the worst case, does not. Before the possibility of assistance from modern medicine, birth canals that did not fit the child’s body resulted in broken bones or, at worst, deaths of both mother and child during childbirth. The child could not leave the maternal body and serious birth injuries resulted. Hormonal problems affecting the birth canal include the cervix not opening despite contractions.It should be at least about 10 cm open for smooth delivery – if it does not open at all or if its opening stagnates despite contractions, the baby cannot leave the uterus. An emergency cesarean section becomes necessary, just as in the case of an unsuitable pelvis. Furthermore, in the birth canal, the child may wrap its own umbilical cord around its neck and either suffocate while still in the birth canal or suffer such severe damage from the lack of oxygen that it dies minutes or hours after birth. Depending on the baby’s position, it may not be born naturally through the birth canal at all – the pelvic end position with the feet forward is particularly problematic for natural birth.
