Sharpen the head and drill in: why should the fetal head be reshaped when the fetus passes through the birth canal?

One day, a woman who had just given birth asked: “little red sister, when I saw the B-ultrasound, my baby’s head was round and bulging. Now, after the baby came out, how did the head become sharp?” < / P > < p > the skull of the newborn is not fully developed, and there are many gaps between the bones. Each bone of the skull cap is connected by connective tissue membrane, and these gaps between the skulls are called cranial fontanelle. The largest cranial fontanelle is prismatic and located in the front of the sagittal suture, which is called anterior fontanelle. That’s what we call fontanelle. In addition, the posterior fontanel was triangular at the intersection of sagittal suture and herringbone suture. There is anterolateral fontanelle under the anterior parietal bone. There is posterolateral fontanelle in the posterior inferior corner of parietal bone. There are four fontanels. < / P > < p > for natural childbirth, people pay more attention to the puerpera, and pay attention to how the puerpera overcome the pain of uterine contraction, make great efforts to make the fetus born. In fact, in the mother’s stomach, the fetus also made a lot of efforts. < / P > < p > in the process of delivery, the fetus should come out from the gradually opened uterine orifice, descend to the mother’s pelvis, and finally pass through the birth canal and be delivered from the birth canal. The process of crossing will last for several hours. When crossing the birth canal, the fetus will move forward like an internal rotation, that is, rotating around the longitudinal axis of the pelvis. If the fetal head is too big to pass through the birth canal, the fetus will try to find a way again. It will change the shape of its fetal head, that is, it will become smaller and sharper, so as to better cross the birth canal. This process is called fetal crossing Head remodeling. < / P > < p > we have all heard such a saying: sharpen your head and drill in. This is what the fetus does when it gives birth naturally. So some babies are born with a sharp head, and some have a big bag on their head. This is because the head of the fetus is squeezed by the birth canal, and the skull has compliance deformation and is squeezed long. At the same time, the scalp also due to extrusion and the emergence of the first exposed part of the scalp edema, with the finger pressure up to show a sunken drum package, clinically known as tumorigenesis. < / P > < p > seeing that the baby’s head is deformed after birth makes the novice parents very distressed and even more afraid that the head shape will not change back to its original shape. Parents don’t have to worry. This deformed head shape is a stopgap measure for a smart fetus. It can be recovered after birth. In a few days, the baby’s scalp edema will subside, and the skull will return to its original shape and become round again. < / P > < p > when it comes to fetal head remodeling, in general, the head deformation ability of full-term fetus is stronger, and it is easier to give birth through the mother’s birth canal. However, after the expected delivery period, for example, the fetus of 41-42 weeks, the fetal head is relatively hard, and it is not easy to deform and reshape the fetal head in the process of delivery, and it is easy to have dystocia. That’s why we need to give oxytocin to some women who have passed their due date. < / P > < p > another point is that during pregnancy, pregnant women should pay attention not to take too much calcium. Excessive intake of calcium, easy to cause premature calcification of fetal bones, fetal skull will not only affect the smooth production, but also lead to premature closure of the anterior fontanel, generally around 1 year old baby fontanel closed. Will restrict the baby’s brain development, affect intellectual development. 08/17/2020