Uterine atony is a medical condition characterized by the loss of uterine muscle tone after birth. It is the main cause of more than 75-80% of the cases of severe haemorrhage occurring in the postpartum and poses a lot of risks to the health of the mother.
What happens to the uterus after birth?
After the baby is born and the placenta is eliminated, normally the contractions of the uterine muscles close the blood vessels and reduce blood flow, which contributes to blood clotting and to prevent bleeding. Postpartum uterine contractions are natural and have the role of helping the uterus recover after birth and return to normal size, before pregnancy.
During labor and birth, doctors are very careful and take many precautionary measures to prevent atonia. Effective control of labor stage 3 helps prophylaxis of uterine atony. Even if it does occur, active control of this stage reduces the severity of its manifestation. The measures needed to control labor include:
- administration of oxytocin immediately after birth;
- gentle pulling of the umbilical cord at birth;
- fast cutting of the umbilical cord.
What are the causes of uterine atony?
It is not possible to speak of exact causes of the affection. Rather, it is a series of risk factors that may occur during pregnancy, or after birth, and contribute to the loss of uterine muscle tone:
- uterine overdistension (in the case of multiple pregnancies);
- multiple births;
- fetal macrosomia;
- prolonged labor;
- treatment with magnesium sulphate in preeclampsia;
- use of halogen anesthesia, etc.
What are the signs and symptoms?
The main sign of uterine atony is hemorrhage, which often appears vaginally, but also locally, in the uterus. It may be moderate or massive and may induce a hypovolemic shock (pulse increase, hypotension, pallor, cold skin, anxiety, etc.).
What complications can occur?
Postpartum hemorrhage poses a number of problems for the mother's health, and if not treated in time, it can cause death. Some of the most common complications in uterine atony include:
- iron deficiency anemia with fatigue;
- severe respiratory distress;
- kidney failure or urinary tract injury;
- uterine synechia;
- pelvic hematoma;
- hypopituitarism (Sheehan syndrome);
What is the treatment of uterine atony?
The treatment is aimed primarily at controlling the main symptom: hemorrhage or hypovolemic shock, if it occurs. In this regard, the measures consist of the administration of oxygen and medicines to stop the bleeding, but also to put on a blood transfusion to compensate for the losses.
Subsequently, physicians will try several therapeutic methods to stimulate uterine muscle tone and restart uterine contractions.
It is possible to resort to strong local massage, which restarts muscle tone, but also to administer oxytocin, a substance that promotes muscle contractions and returns the uterus to normal size. To facilitate the massage and other therapeutic actions, it is necessary to drain the bladder continuously. These procedures also help in recovery in case of uterine overdistension, that is, excessive enlargement of the uterus, especially in case of fetal macrosomia or multiple pregnancy.
If an exploratory action is taken on the uterus, to massage and remove clots and placenta or other tissues, doctors will also administer antibiotics to reduce the risk of infection.
Uterine embolization is a procedure that is rarely used but is effective in stopping the abundant bleeding. It is considered an interventional radiological procedure that is done by injecting special substances.
If drugs, massage and oxytocin fail to block bleeding or restart muscle contraction, surgery is required. Initially the closure of the blood vessels that supply the uterus is attempted, but if this is not possible, the doctors have to resort to hysterectomy (removal of the uterus). But this only happens in very rare and very serious cases, when the atonia and postpartum haemorrhage are not discovered in time and serious complications occur.