Fetal bladder performs certain functions both during pregnancy and during childbirth. During pregnancy, it is a shell with an aqueous medium within which the unborn child develops.
Amniotic fluid protects the baby from mechanical external influences and protects the umbilical cord from being squeezed between the baby and the uterine wall. They create conditions for active movements of the future baby, thanks to which his upper and lower limbs develop.
In addition, fetal membranes are a natural barrier to infection.
In the first stage of labor, the fetal bladder performs the function of a hydraulic wedge. During contraction, the uterus contracts, and the fetal bladder, filled with water, rushes into the cervix. Pressing it from the inside, he forces it to open.
However, the “hydraulic wedge” performs its task only before the opening of the cervix at 6–7 cm. The baby’s head further contributes to its further opening, which presses against the edges of the neck at the moment of contraction.
At the height of one of the contractions the bubble may burst, and the water will be drained independently.
Sometimes there is a need for artificial dissection of the fetal bladder. Assessing the situation, the decision is made by the doctor.
He also explains to the woman why this manipulation is necessary.
The opening of the membranes causes the release of biologically active substances (prostaglandins) into the blood, which are “responsible” for the contractile activity of the uterus. Therefore, when it is necessary to stimulate labor, a woman is given an amniotomy.
One of the indications for such manipulation is postponed pregnancy.
With a period of 41 weeks and more, it is difficult to determine whether the child suffers, whether he has enough oxygen. In a similar situation, amniotomy can be offered to a woman to stimulate childbirth. But first, doctors with the help of drugs will prepare for the birth of the cervix.
Under their influence, it will begin to shorten and soften. At the opening of the fetal bladder, the mechanism of labor starts reflexively: the head of the crumb falls, there is pressure on the cervix, which starts the process of its opening.
It also happens that the fetal bladder has to be opened to initiate labor before the prescribed period (up to 40 weeks). This may be required both in the development of serious complications of pregnancy, and in the event that the expectant mother suffers from diseases of the cardiovascular or central nervous system, disorders in the liver and kidneys.
Artificial labor induction is also resorted to during hypoxia of the unborn child or when intrauterine diseases or disorders that threaten his life and health are detected. With such a development of events, the life and health of a woman, as well as the baby’s need for extrauterine treatment, outweigh the risks arising from its premature birth.
The possibility of carrying out amniotomy in such situations depends on the degree of “maturity” of the cervix, so this method is usually used in multiparous women.
For example, the indication for early opening of the membranes of fetal bladder may be Rh-conflict. With its rapid growth at the 34-36th week of pregnancy, doctors begin to prepare the cervix for childbirth and initiate them with the help of amniotomy. The most serious of the indications for premature birth by the mother is preeclampsia – toxicosis that occurs in late pregnancy.
Its symptoms are high blood pressure, swelling and protein in the urine. With increasing blood pressure, increasing the level of protein in the urine, a woman is hospitalized. If conservative treatment methods are ineffective, the optimal delivery option is chosen.
When the expectant mother is allowed to give birth on her own, amniotomy is required to speed up the process.
Amniotomy is also resorted to directly in the process of childbirth. One of the indications – a lot of and shallow water. If there is little water, doctors talk about a “flat” fetal bladder.
Due to the lack of amniotic fluid, the membranes are stretched on the baby’s head and the “hydraulic wedge” is not formed during the contraction, the pressure on the cervix is too weak. It turns out like with vaginal examination.
Since the bladder does not fulfill its function and does not contribute to the opening of the cervix, it only hinders and delays the delivery, makes amniotomy.
In the second case, when self-opening of the fetal bladder, there is a risk that, together with a large flow of amniotic fluid, the handle or loops of the umbilical cord will fall out and the descending head will squeeze them, disrupting their circulation. To avoid complications, the obstetrician, opening the bladder, gently and slowly lowers the amniotic fluid and waits for the baby’s head to fall down and press against the entrance to the pelvis.
Also, an indication for amniotomy during labor is a weakening of labor. This can happen due to hormonal disorders, physical fatigue and prolonged labor.
The doctor monitors the progress of contractions (their frequency, strength, duration) and, confirming the diagnosis, makes amniotomy. Manipulation allows you to intensify childbirth, and a woman – to save the forces that will be needed for the productive period.
In case of multiple pregnancies, amniotomy is resorted to in the second stage of labor if the fetal bladder of the second child did not break open independently 5–10 minutes after the birth of the first baby.
An obstetrician performs an amniotomy outside of a contraction with minimal fetal bladder tension. The hole is made with a special tool for vaginal examination.
Then the doctor inserts fingers into the hole, spreads the shells and slowly releases water by the arm, waiting for the baby’s head to sink and press against the entrance to the small pelvis. The woman at this moment is lying on her back. The procedure is painless and completely safe for both the expectant mother and her baby.
After an amniotomy, a woman is recommended to calmly lie down for a few minutes.
Manipulation is always carried out under the control of a cardiotocograph. Since the uteroplacental blood flow decreases in response to the procedure and the baby’s heart begins to beat less frequently, the obstetrician closely looks at the sensor readings, monitoring the recovery of the heart rhythm.