![]() ( c) An ultrasound image of translabial that displays the rotation of the head that has reached the ischial spines, and the diameter of the occipito-front is aligned with the anteroposterior diameter of the pelvis. ( b) Transabdominal ultrasound image showing the progression of the head toward the close medium and rotation ( right). ( a) Illustration of a transabdominal ultrasound showing the mechanism of commitment, the bending of the head down the narrow upper left oblique diameter according to the transverse ( right). This study provides evidence that digital assessment of fetal head station is unreliable. Undiagnosed “high” stations accounted for 22% of the errors made by residents, and 16% of those made by attending physicians. The mean error rate in the diagnosis of engagement was 12%, and this misdiagnosis was distributed equally between false-positives and false-negatives. Numerical errors occurred in 50–88% of cases for residents (average experience 2 years) and in 36–80% of cases for attending physicians (average experience 9 years). The error in the diagnosis of station was assessed by calculating the difference between the true station (established by sensors in the birth simulator) and that determined by the clinician’s fingers. A fetal head mannequin was placed in 11 different stations in a random order. He used a birth simulator with objectively defined stations and studied the reliability of clinical assessment of engagement and fetal station in 57 physicians (32 residents and 25 attending physicians). made an important contribution to this debate when he rigorously assessed the accuracy of station diagnosis with digital examinations. Recent studies, however, dispute these findings and found clinical examination of fetal descent and position to be subjective with high interobserver variation. In one study from the 1980s, repeatability of digital examinations was found to be acceptable. Traditionally, labor progression has been assessed by digital examination of cervical dilatation and fetal descent. Prolonged labor is defined when cervical dilatation crosses the “action line.” Some hospitals use partographs from the Dublin school of “active management of labor” and expect one-cm dilatation/hour (the slope of the alert line), whereas other hospitals define prolonged labor when cervical dilatation is <1.2 cm/h in nulliparous women and <1.5 cm/h in parous women. Philpott suggested in 1972 to use “alert lines” and “action lines” (4 h from the “alert line”) in partographs to evaluate labor progress, and WHO has adopted this method. He has documented a strong correlation between cervical dilatation and station and an association between high station at arrest of labor and adverse outcome. ![]() In 1954, Friedman introduced the partograph. Minus five corresponds to the pelvic inlet, zero to the level of the ischial spine, and plus four corresponds to the pelvic floor (Fig. The fetal descent in the birth canal is assessed by vaginal digital examinations and related to the ischial spine (Fig. ![]() Müller first described the concept of station in 1868. The mentum (chin) is the presenting part.The fetal lie can be longitudinal or transverse, presentation describes the lowest fetal part in the birth canal, position means how the fetus is rotated, and station refers to the level of the presenting part in the birth canal. The brow or forehead is the presenting part. The top of the head is the presenting part. This is an uncommon fetal position and a vaginal birth is unlikely.Ĭommonly, this skull diameter is too large to pass through the pelvis. Many fetuses assume this attitude early in labor but convert to complete flexion as labor progresses. This position is commonly called the fetal position. The back is usually arched, which increases the degree of hyperextension. In complete extension, the head and neck of the fetus are hyperextended and the occiput touches the fetus’s upper back. In partial extension, the head of the fetus is extended, with the head pushed slightly backward so that the brow becomes the first part of the fetus to pass through the pelvis during birth. Moderate flexion (aka military position or sinciput), the head of the fetus is slightly flexed but held straighter than in complete flexion. In complete flexion, the head of the fetus is tucked down onto the chest, with the chin touching the sternum.
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