The reason why the fetus is beyond the expected date of delivery
1, which is caused by family genetic factors.
Female members of the family have had this kind of medical history, or the expectant mother has had this kind of situation before, so the probability of overdue pregnancy during pregnancy will greatly increase. In addition, if you carry recessive genetic diseases such as placental sulfatase deficiency, it may also lead to extended pregnancy of expectant mothers.
2. The fetus is deformed.
Fetal malformation may lead to insufficient hormone secretion of expectant mothers, leading to extended pregnancy during pregnancy. If there is anencephaly, the absence of pituitary gland will reduce the estrogen secretion of expectant mothers, which will eventually lead to overdue pregnancy.
3. The ratio of estrogen and progesterone is unbalanced.
When a normal pregnant expectant mother gives birth at full term, estrogen will increase and progesterone will decrease. If estrogen can not be significantly increased, it will lead to an increase in the proportion of progesterone, thus inhibiting the normal role of prostaglandin and oxytocin, which will lead to extended pregnancy during pregnancy.
4. The uterine contraction stimulation reflex is weakened.
In some cases of overdue pregnancy, the fetus is larger, which may lead to fetal head-basin asymmetry or fetal malposition. In this process, the first exposed part of the fetus (that is, the first exposed body part of the fetus during delivery, usually the first exposed head of the fetus) can not be in close contact with the lower uterine segment and cervix, resulting in reduced reflex uterine contraction and premature pregnancy of expectant mothers.
The harm of the fetus beyond the expected date of delivery
1, dystocia
If the reaction of overdue pregnancy lasts too long and the function of placenta does not decrease, then the fetus will continue to develop and grow in the uterus of the expectant mother, and finally form a huge fetus (that is, the fetus weighs more than 4.0 kg and the length is more than 55 cm), which will eventually make the baby's head hard and shoulder wide, increase the difficulty of production, and increase the chances of pregnancy diseases such as fetal intracranial hemorrhage and maternal birth canal injury.
2, leading to fetal death
If the expectant mother's overdue pregnancy lasts too long, the greater the chance of premature birth syndrome. This type of fetus is prone to death. Even if they are born successfully, their health will be much worse than that of normal delivery children, and they will often die of dehydration, anemia and lung infection.
3. Prolonged working hours
The fetus beyond the expected date of delivery is generally larger, the fetal skull is hardened and the shoulders are widened, so the fetal head is not easy to deform, the fetal head is not easy to fall, and the delivery time will be longer.