Donald School Journal of Ultrasound in Obstetrics and Gynecology, July-September 2012;6(3):257-269 257 DSJUOG Applications of Ultrasound in Prelabor and Labor REVIEW ARTICLE Applications of Ultrasound in Prelabor and Labor Dominic Iliescu, Panagiotis Antsaklis, Daniela Paulescu, Alexandru Comanescu, Stefania Tudorache Aris Antsaklis, Iuliana Ceausu, Liliana Novac, Nicolae Cernea, Asim Kurjak 10.5005/jp-journals-10009-1249 ABSTRACT Ultrasound is a crucial part of everyday obstetrical practice and becomes more and more important in the management of traditionally clinical aspects of obstetrics, such as management of labor and delivery, offering a possibly more objective method of examination. The rate of labor induction has doubled in the last two decades and more objective methods are needed to assess the possible outcome of an induction and help clinicians in order to counsel women appropriately. Regarding the management of labor there is extensive evidence that clinical assessment during labor is not accurate, with potential consecutive major implications in the decision-making and the prognosis of the delivery mode. Several studies have shown that ultrasound is an objective method of assessing labor and its progress and is very helpful in decision-making for instrumental deliveries. The purpose of this article is to review the evidence available in literature regarding the benefits and the role in general of ultrasonography in prelabor and labor. Keywords: Ultrasound, Labor, Prelabor, Sonopartogram. How to cite this article: Iliescu D, Antsaklis P, Paulescu D, Comanescu A, Tudorache S, Antsaklis A, Ceausu I, Novac L, Cernea N, Kurjak A. Applications of Ultrasound in Prelabor and Labor. Donald School J Ultrasound Obstet Gynecol 2012;6(3):257-269. Source of support: Nil Conflict of interest: None declared INTRODUCTION It is well-established that clinical evaluation during labor is a subjective method, which is not accurate and depends on the experience of the performer. Ultrasound examination on the contrary is a quick, safe, noninvasive method which has been proposed as a more objective alternative for monitoring labor. Sonography has been proposed by different studies as an objective method for planning time and mode of delivery and for intrapartum monitoring, as well as decision-making for instrumental delivery. Aim of this article is to review the evidence regarding the use of ultrasound in assessing labor and delivery. ULTRASOUND IN PRELABOR There is an increased use of ultrasound in antenatal monitoring and assessment of labor, which has been supported by recent evidence in the literature. The new ultrasound machines are designed to enable service and allow obstetricians to routinely provide good quality ultrasound services, including prelabor assessments. 1 Ultrasound examination offers valuable information before the beginning of labor, such as placental localization, presence of neck-cord or vasa previa, fetal presentation, weight, well-being, depiction of prematurity and prolonged pregnancy information. The collateral applicability of ultrasound during labor has also been studied in literature. For example, assessment before epidural catheter placement, 2-8 intrapartum maternal symphyseal separation by transverse suprapubic ultrasound examination, 9 intrapartum fetal behavior and prediction of adverse perinatal outcome based on amniotic fluid amount or biophysical profile, 10-19 depiction of the molding and caput succedaneum during, but also before labor, 20-26 maternal 27,28 and fetal 29-43 intrapartum pulsed Doppler blood flow assessment, intrapartum myometrial thickness changes, 44 ultrasound use in the third stage of labor, 45-52 or the assessment of the postvoid residual volume in laboring and postpartum women with or without epidural analgesia. 53-56 In the majority of these cases, until now the clinical significance is unclear and remains part of research protocols. Prediction when Planning Spontaneous Labor A predictive method which could estimate with good sensitivity the possibility of the mode of delivery (e.g. vaginal delivery or cesarean section) would be beneficial regarding both health economics and also the medical outcome of the pregnancy, such as pelvic floor trauma 57-60 or other psychological consequences to the mother 61-63 and the perception of personal failure. 64 According to latest evidence it appears that such estimation could be possible before induction of labor and during labor, but if such predictions are established earlier, they should have a much greater benefit. We should also mention the increasing rate of ‘on demand’ cesarean section, 65,66 which frequently is motivated by their desire to avoid a traumatic delivery, 67,68 studies so far have failed to detect a large proportion of pregnancies at risk of these outcomes. 69-72 Dietz et al studied the correlation between antenatal bladder neck mobility and delivery mode 73 and confirmed that it is possible to assess prenatally fetal head engagement with translabial ultrasound. 74 The quantification of head engagement was performed using two methods: In the first method, a line was drawn through the inferoposterior symphyseal margin and parallel to the main transducer axis. 75 In the second method, the line of reference was a