Measurement of head compression during labor: Preliminary results

Abstract

To study the pressure to which the fetal head is exposed during the second stage of labor, an instrument was designed to measure continuously the pressure between the presenting part and the birth canal on both sides of the fetal head. Pressure parameters during and between the uterine contractions were calculated from 42 spontaneous vertex deliveries presenting as occiput anterior. During the second stage the overall average of the mean maximum head pressure during uterine contraction was 31.8 +/- 11.0 kPa, that of the mean head pressure measured 13.3 +/- 4.8 kPa during uterine contraction and 5.5 +/- 3.7 kPa during the interval between contractions. The pressure on the fetal head was about twice as high as the amniotic pressure. It increased towards the end of labor. The objective measurement of fetal head pressure is the prerequisite in the study of the relationship between birth-related injuries and excessive head compression during parturition.

Synergistic Effect of Vaginal Trauma and Ovariectomy in a Murine Model of Stress Urinary Incontinence: Upregulation of Urethral Nitric Oxide Synthases and Estrogen Receptors

“…The pressure on the vaginal sidewall can reach 240 cmH 2 O during the peak contractions if active labor is maintained for more than 30 min, which can cause microcirculatory ischemia and overstretching of the pelvic floor muscles, pubourethral ligaments, and nerve tissue; these combined events can lead to SUI [31–33]. Birth trauma and menopause play important roles in the development of SUI [34].…”

A mouse model of simulated birth trauma induced stress urinary incontinence

“…1 This damage occurs as a direct result of the large ratio of the baby's head to the birth canal in humans. Pressure to the vaginal sidewall can reach 240 cm H 2 O during the peak of contractions, 11 which is sufficient to cause microcirculatory ischemia to muscle and nerve tissue, if it is maintained for more than 30 min. 12 In addition to ischemia, the stretch injury may cause alteration of the composition and function of the lower urinary tract (LUT) tissues.…”

Pelvic floor dysfunction, and effects of pregnancy and mode of delivery on pelvic floor

“…The pressure of the fetal head during birth was measured to be two-fold more than the amniotic pressure, and this pressure increases toward the end of the birth. Hence, it is stated that fetal head pressure is one of the most important factors for POP development in birthrelated injuries [17]. Another study reported that occiput posterior presentation and macrosomia work synergistically, increasing the risk of perineal trauma [18].…”