One of the leading causes of maternal deaths in the 21st century is postpartum haemorrhage. A short period of euphoria in the obstetrics associated with the success in the treatment of hypotonic and coagulopathic haemorrhage came to an end with a new problem, which had been previously foreseen and is often iatrogenic — the invasion of the placenta into the uterus in the area of the postoperative scar.
One of the leading causes of maternal deaths in the 21st century is postpartum haemorrhage. A short period of euphoria in the obstetrics associated with the success in the treatment of hypotonic and coagulopathic haemorrhage came to an end with a new problem, which had been previously foreseen and is often iatrogenic — the invasion of the placenta into the uterus in the area of the postoperative scar.
A clear connection between the placental invasion and the presence of a uterine scar after caesarean section and placental presentation has been proven, since the area of villi invasion is most often located in the lower segment of the anterior uterine wall, that is, at the site of its typical incision. Unreasonable preoccupation with operative delivery using caesarean section led to an increase in the proportion of uterine haemorrhage associated with abnormal placental attachment. When the placenta is located in the scar area after the previous caesarean section, it grows not only into the uterine wall but also into adjacent organs in 10-60 % of cases.
Haemorrhage caused by placental invasion takes the first place in the structure of maternal deaths caused by haemorrhage. The frequency of abnormal placental attachment in recent decades has increased 50-fold (1 case per 25-50 thousand births in the middle of the 20th century vs 1 case per 500-1,000 births in the 21st century). The cause of this pathology is most often the previous inflammatory processes (metroendometritis), postoperative scars on the uterine wall, submucous myoma nodules and uterine malformations. The connection between the placenta and the uterus in these cases may be too intimate that leads to the pathological course of the third stage of labor.
Normally, the chorionic villi invade into the functional layer of the endometrium. And only some of them, the so-called anchoring villi, invade into the basal layer. If the villi invade into the basal layer but do not go beyond it, this indicates a dense attachment of the placenta (placenta adhaerens). The invasion of villi outside the basal layer is called a true placenta accreta. The deeper invasion of villi into the muscular layer is called placenta increta. If the villi invade into all layers of the uterus, there is placenta percreta.
