Methods of evaluating labor progress in contemporary obstetrics

Abstract

Assessment of progress in labor is one of the foremost problems in obstetrics. Obstructed labor increases danger to maternal and fetal life and health, and may be caused by birth canal pathologies, as well as inefficient uterine contractions or failure of cervical dilation. Such obstructions require the use of vacuum extraction, forceps, or a Caesarean section. Operative delivery should be performed only when specifically indicated. Conversely, postponing an operative delivery when the procedure is necessary is detrimental to the neonatal outcome. Therefore, it is advisable to make the decision on the basis of objective, measurable parameters. Methods of evaluating the risk of labor disorders have evolved over the years. Currently, ultrasonography is used for fetal biometric measurements and weight estimation. It helps to evaluate the risk of labor disorders. This method, however, is limited by a relatively large measurement error. At present, vaginal examination is still the primary method of evaluating labor progress, although the technique is known to be operator-dependent and poorly reproducible. Recent publications suggest that intrapartum translabial ultrasonography is more accurate and allows for an objective assessment of labor progress. Recent studies have evaluated fetal head engagement based on the following parameters: angle between the pubic symphysis and fetal head, distance between the presenting point and the interspinous line and fetal head direction in the birth canal. Each of the described parameters allowed for an objective assessment of head engagement but no advantage of any particular parameter has been revealed so far.