What is meant by regular contractions?
Regular uterine contraction refers to a symptom that occurs before childbirth. If the frequency of uterine contractions continues to increase, the time interval between two contractions gradually shortens, from originally 30-60 minutes apart, lasting for several minutes each time, to later occurring every two or three minutes, lasting for about half a minute each time. In addition, the symptoms of maternal low back pain become more severe, and there is also soreness in the lumbosacral region. The uterine opening enlarges and the fetal head descends. This situation is known as regular uterine contraction.
1. Rhythmicity: Normal uterine contractions are involuntary, rhythmic, and paroxysmal contractions of the uterine body. Each contraction gradually intensifies from weak to strong, maintains for a certain period of time, and then gradually weakens from strong to weak until it disappears into the intermission phase. During the intermission phase, the uterine muscles relax, and contractions repeat until the entire childbirth process ends.
2. Symmetry and Polarity: Normal uterine contractions originate from the corners of both sides of the uterus, migrate towards the center of the uterine fundus, and then expand downwards, forming a symmetrical pattern called the symmetry of uterine contractions. The contractions are strongest and most persistent at the bottom of the uterus, gradually weakening downwards, known as polarity.
3. Shortening and Recovery: The smooth muscles of the uterine body are the active contracting part. During each uterine contraction, the muscle fibers of the uterine body shorten and widen, relax during the intermission, but cannot fully recover to their original length. After repeated contractions, the muscle fibers become shorter and shorter, known as "shortening and recovery." With repeated contractions of the uterus, the muscle fibers become thicker and shorter, the upper segment of the uterus becomes thicker, and the lower segment is stretched and expanded, becoming longer and thinner. At the junction of the upper and lower segments, a ring-shaped groove is formed due to the different thickness of the muscle layers, known as the physiological shortening and recovery ring.
