Many expectant mothers hope for a natural birth, which benefits not only the mother but also the baby. So how can one achieve a smooth natural delivery?
Natural birth allows the baby's brain and lungs to develop further through compression during passage through the birth canal, resulting in healthier and smarter children compared to those delivered by cesarean section.However, there are two sides to every story. This natural birth process involves enduring pain for over ten hours. While it may not be as excruciating as some mothers describe, it still requires significant endurance. Therefore, they urgently want to know how to minimize suffering and navigate childbirth smoothly.
So what factors influence a woman's natural childbirth?
1. The Force Expelling the Fetus
When a mother's due date arrives, it signals the fetus has matured and must be born. Otherwise, the placenta's nutrient supply system gradually deteriorates until it ceases. Yet babies remain unaware of this urgency—content to eat and sleep comfortably in the womb, reluctant to embark on the arduous journey into the world.Therefore, expectant mothers require a force to expel the fetus—medically termed "labor force." This expulsion force possesses distinct characteristics: rhythmicity, symmetry, polarity, and retraction. These properties ensure the baby is safely delivered without harm, while simultaneously allowing the lower uterine segment, cervix, and vagina to gradually dilate passively, facilitating a smooth birth.
Generally, labor contractions begin during late pregnancy, occurring more frequently as the due date approaches. For the mother, this manifests as sudden, irregular episodes where the uterus feels like a ball—tightening and hardening before quickly relaxing. The true sign of active labor is two contractions within ten minutes, occurring regularly and accompanied by cervical dilation and descent of the fetal head.From this point, full cervical dilation (10 cm) to delivery typically takes 12–14 hours. For the mother, this period involves experiencing regular waves of abdominal pain (contractions) that progressively intensify. At this stage, some expectant mothers may feel overwhelmed or lose confidence, prompting pleas to the doctor: "Please give me an induction shot or pain relief!"
Here, we must inform expectant mothers: Only through sufficient duration of contractions can the cervix fully dilate, facilitating the baby's descent. If this process is too rapid, too slow, too intense, or too weak, it can cause serious harm to both mother and baby. Doctors understand this principle and will not intervene without special circumstances. Expectant mothers should also grasp this truth—for first-time mothers, completing this process is difficult without enduring a certain period of pain.
II. The Fetal Passage Through the Vagina
The pathway through which the fetus emerges from the vagina is medically termed the birth canal, comprising both the bony passage and the soft birth canal.
The soft birth canal is a curved passage formed by the lower uterine segment, cervix, vagina, and pelvic floor soft tissues. Normally closed, it gradually dilates passively during labor due to powerful uterine contractions and pressure from the descending fetal head. When dilation reaches 10 centimeters in diameter, the baby can pass through smoothly.
The term "birth canal" commonly refers to the bony birth canal (pelvis). This is not a smooth, vertical passage but an irregularly shaped, elliptical, curved passage only 8–9 centimeters deep. Passing through it is no easy feat for the baby. Moreover, two barriers (the ischial spines) are positioned within this irregularly curved passage, forcing the baby to pass between them.The average distance between these points is 10 centimeters, making larger-headed babies prone to becoming stuck.
From the above description, it becomes clear that a baby cannot descend vertically through the birth canal to enter the world. Instead, it must rotate at each stage to align its head with the largest diameter of the mother's fixed birth canal.Many babies experience obstructed labor when their progress is halted at a specific point in the birth canal due to various factors. If the mother's pelvis is abnormal (underdeveloped or injured), certain dimensions within this passage may be reduced, causing obstruction during the baby's descent.Sometimes the mother's pelvic dimensions are normal, but the baby becomes a chubby little one (macrosomic infant) due to excessive eating and sleeping in the womb. Ultimately, during delivery, the baby may be blocked from passing through the fixed maternal dimensions because its head is too large or its body too fat.
III. Fetal Conditions
The baby's size and position within the mother's uterus are crucial factors in natural childbirth.
The average biparietal diameter (BPD) of a full-term fetus is 91–93 mm, while the narrowest pelvic diameter in most mothers is approximately 100 mm. Therefore, when a baby's head is large, with a BPD approaching 100 mm, passage through the birth canal may become difficult.Generally, a mother's pelvis can accommodate a baby weighing 3000–3500 grams without significant issues. However, when the baby's weight exceeds 4000 grams (macrosomia), passing through the relatively fixed birth canal becomes challenging. Therefore, expectant mothers are advised to maintain balanced nutrition to prevent the fetus from becoming overweight. Macrosomia not only increases the risk of delivery complications but also contributes to childhood obesity, potentially affecting the child's future development.
Some babies, despite being small, may adopt unfavorable positions in the uterus (a normal position is head down, arms crossed over the chest, legs tucked tightly against the abdomen). For instance, if a baby is lying face up, with the buttocks or legs downward, or with the head not snug against the chest, it may struggle to rotate within the birth canal to align with its shape. This can cause the baby to become stuck, hindering delivery.When this occurs, the mother has no choice but to seek medical assistance. IV. Psychological Factors in Mothers Anxiety and tension not only affect a mother's emotional state but also deplete her physical strength, heightening sensitivity to pain and disrupting the transmission of commands from the cerebral cortex nerve center.For the baby to enter the world, uterine contractions must initiate and progress labor under the direction of the cerebral cortex command center. The state of mental factors directly influences the transmission of these commands, potentially causing contractions to be too strong or too weak. This directly affects the baby's descent and rotation, slowing labor progression.
Prolonged stay in the uterus increases the risk of fetal hypoxia, asphyxia, or even death. Even if the baby survives, intellectual disabilities may occur. Additionally, psychological factors can contribute to postpartum hemorrhage.
As the baby grows within the womb, expectant mothers often become increasingly anxious. They turn to books and seek advice from friends with childbirth experience.However, most do not receive satisfactory answers, and some even encounter counterproductive advice. Some women who have given birth say, "The pain during childbirth felt like I was dying." Others claim, "Cesarean sections are better—they use anesthesia, and it's over quickly. But I heard C-sections are bad for the child's future development." Clearly, these experiences are one-sided, based on individual feelings and interpretations, and lack scientific rigor.