Post-term pregnancy harms both mother and baby.
Delivery before 37 weeks is considered premature birth. Delivery after 42 weeks (i.e., two weeks past the due date) is termed post-term pregnancy. Primary causes include: maternal endocrine imbalance (excessive progesterone and insufficient estrogen, hindering uterine contractions that initiate labor) and genetic factors (often with a family history of post-term pregnancy or fetal abnormalities).
Common examples include anencephaly, where the lack of skull and minimal presenting part fails to adequately stimulate uterine contractions, making labor initiation difficult. Additionally, fetal gender is determined by chromosomes and has no bearing on the timing of delivery. Thus, the claim that "girls are late bloomers" or that post-term pregnancies are always girls lacks scientific basis.
As the saying goes, "When the melon ripens, the stem falls."When the fetus is fully developed, birth occurs naturally. If the "fruit is ripe but the stem won't fall," it indicates placental aging. At this stage, the placenta's ability to exchange and transport substances declines, directly affecting oxygen and nutrient supply to the fetus. This leads to chronic hypoxia and malnutrition in the fetus. Furthermore, the fetus may struggle to tolerate the pressure from uterine contractions during labor, increasing the risk of asphyxia and death.
Post-term pregnancy also harms the mother. By this stage, the fetal skull hardens, the fontanelles shrink, and the occipital protuberance becomes prominent. The fetus's ability to adapt to the birth canal during labor diminishes, significantly increasing maternal complications—most notably, a higher incidence of difficult labor. Therefore, if a pregnant woman reaches her due date without signs of labor, she should promptly visit the obstetrics department for examination.