Medically, pregnancy lasting more than 14 days past the due date is termed post-term pregnancy, during which fetal mortality rates are three times higher than normal.
The placenta has a finite lifespan. Approximately two weeks past the due date, placental function begins to decline, leading to insufficient oxygen supply and placing the fetus in a state of chronic hypoxia. In post-term pregnancies, the placenta is often smaller than normal at delivery, with scattered white mottling on its surface. Hard, stone-like calcifications may also be visible, indicating placental aging.Due to oxygen deprivation, the fetal heartbeat may become slow and irregular. Simultaneously, increased gastrointestinal motility causes the expulsion of meconium, turning the amniotic fluid grass-green or even dark green, muddy in appearance, while the amniotic fluid volume progressively decreases.In post-term pregnancies, fetal growth often ceases. The fetus may appear elongated and thin, with wrinkled skin and a shrivelled appearance resembling a small elderly person. Due to placental aging and diminished function, the fetus may die suddenly in utero or shortly after delivery. Some infants die from asphyxia or pneumonia caused by inhaling meconium-stained amniotic fluid during delivery.
What should be done for post-term pregnancy? For women with regular menstrual cycles of 28 days, if labor does not commence within 10 days past the due date, medical examination is necessary to assess placental function decline. Based on the degree of decline, the decision will be made between induction or cesarean delivery.
Multiple induction methods exist. Rupturing membranes combined with intravenous oxytocin infusion yields high success rates. Simultaneously, observing amniotic fluid volume and color during membrane rupture provides valuable insights into fetal hypoxia and its severity. All induction techniques are safe, cause no pain to the mother, and pose no adverse effects on the fetus.
Of course, post-term pregnancy does not necessarily result in fetal or infant death. Sometimes, even after the due date has passed, placental function remains adequate—much like how some elderly individuals remain remarkably robust. Nevertheless, as a precaution, we must not rely on luck. When faced with a post-term pregnancy, it is best to seek medical examination at the hospital as soon as possible.