Anatomy & Organs

Birth Canal – Structure, Function & Diseases

Birth canal

The birth canal encloses all of the female sex organs that the baby must pass through during birth . During contractions, it leaves the uterus through the opened cervix 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 over a period of 9 months. In contrast to fish or frogs, for example, people can only give birth to one child per birth, since it is much more likely to survive the birth and the first critical months of life than a freshly 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 go through this path at birth in order to leave the mother’s body. In addition to the vagina and the cervix in a broader sense, the birth canal also includes 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, since the mother can protect her child as long as it is in her own body.

Anatomy & Structure

In the narrower sense, the human birth canal consists of the cervix and the 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.As a result, no liquid can escape and hardly any germs can penetrate upwards into the uterus, since they have to pass the cervix to do so. It opens during the course of the birth and thus opens the way for the baby into the further birth canal. If this does not happen, natural childbirth 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 die 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 part of the birth canal. The child initially lies in the mother’s pelvis before being pushed into the birth canal. Female pelvic bones are wider than males because a child’s head and body must fit through them. If the child cannot pass through this part of the birth canal, a natural birth is impossible.

Function & Tasks

The birth canal is particularly important during the 9-month pregnancy, during which its components offer valuable protection to the unborn baby. Man has only one child per birth solely because he is able to provide a single offspring far better protection than other species.

As a human baby develops, it lies safe and well protected “behind” the protective mechanisms of the birth canal. The acidic environment of the lining of the vagina prevents germs from getting to him before his immune system is developed enough to deal with them. The cervix acts as an additional protection against diseases.

Since the unborn child is also in the mother’s body, she protects herself from enemies at the same time and also protects her child as long as it has not yet started its way through the birth canal – at least that is the evolutionary thought behind this reproductive strategy . When the baby is finally viable after 9 months of gestation , every part of the birth canal allows birth.

The pool is wide enough to let the head and body through. The cervix opens and gives way to the outside. The vagina serves as the final channel through which the baby is pushed through labor .


One of the most common complications affecting the birth canal is the pelvic bone. It is unchangeably formed in the adult woman, so that the child either fits through its form – or, in the worst case, not. Before the possibility of receiving support from modern medicine, birth canals that did not fit the child’s body resulted in broken bones or, in the worst case, death in both mother and child during birth.The child could not leave the mother’s body and serious birth injuries resulted. One of the hormonal problems affecting the birth canal is the cervix not dilating despite labour. It should be open at least about 10 cm for a smooth birth – if it does not open at all or if its opening stagnates despite contractions, the child cannot leave the uterus. An emergency caesarean section will be necessary, just like with an unsuitable pelvis.

Furthermore, it can happen in the birth canal that the child wraps its own umbilical cord around its neck and either suffocates while still in the birth canal or suffers such severe damage from the lack of oxygen that it dies minutes or hours after birth. Depending on the position of the child, it may not even be possible to be born naturally through the birth canal – the breech position with the feet forward is particularly problematic for a natural birth.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.