You are in: eMedicine Specialties > Obstetrics and Gynecology > Labor and Delivery Face PresentationArticle Last Updated: Jun 18, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 6
  Author: Peter G Napolitano, MD, FACOG, Clinical Assistant Professor, Department of Obstetrics and Gynecology, University of Washington; Program Director of Maternal-Fetal Medicine Fellowship, Director of Division of Maternal-Fetal Medicine, Chief of Prenatal Genetic Counseling, Department of Obstetrics and Gynecology, Madigan Army Medical Center Peter G Napolitano is a member of the following medical societies: American Institute of Ultrasound in Medicine, American Medical Association, Association of Professors of Gynecology and Obstetrics, Association of Professors of Gynecology and Obstetrics, and Society for Maternal-Fetal Medicine Coauthor(s): Jason Parker, DO, Staff Reproductive Endocrinologist, Department of Obstetrics and Gynecology, Womack Army Medical Center, Fort Bragg, North Carolina Editors: Gerard S Letterie, MD, Medical Director of In-vitro Fertilization Lab, Associate Clinical Professor, Department of Obstetrics and Gynecology, Virginia Mason Medical Center, University of Washington; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Frederick B Gaupp, MD, Consulting Staff, Department of Family Practice, Assumption Community Hospital; Carl V Smith, MD, The Distinguished Chris J and Marie A Olson Chair of Obstetrics and Gynecology, Professor, Department of Obstetrics and Gynecology, University of Nebraska Medical Center Author and Editor Disclosure Synonyms and related keywords: malpresentation, contracted pelvis, cephalopelvic disproportion, anencephaly, fetal malformation, Leopold maneuvers, Thom maneuver INTRODUCTIONSection 2 of 6
  In a face presentation, the fetal head and neck are hyperextended, causing the occiput to come in contact with the upper back of the fetus while lying in a longitudinal axis. The presenting portion of the fetus is the fetal face between the orbital ridges and the chin. The fetal chin (mentum) is the point designated for reference during a vaginal examination. The mentum can present in any position relative to the maternal pelvis. If the mentum presents in the left anterior quadrant of the maternal pelvis, it is designated as left mentum anterior (LMA). BACKGROUNDSection 3 of 6
Face presentation occurs in 1 of every 250-690 live births, averaging about 0.2% or 1 in 500 live births overall. Causative factors associated with a face presentation are similar to those leading to general malpresentation and those that prevent head flexion. A contracted pelvis or cephalopelvic disproportion, from either a small pelvis or a large fetus, occurs in 10-40% of cases. Multiparity or a large abdomen cause decreased uterine tone, leading to natural extension of the fetal head. A nuchal cord with multiple coils about the neck or fetal thyromegaly also leads to extension of the head. Anencephaly is found in more than 30% of cases of face presentation, and fetal malformation is found in as many as 60%. In one review, up to 90% of cases of fetal face presentations had at least one etiologic factor identified. The diagnosis of face presentation can be made clinically by Leopold maneuvers and/or vaginal examination or radiographically by ultrasound. During Leopold maneuvers, the cephalic prominence is on the same side as the fetal back with an indentation between them, leading the observer to palpate a curvature from the fetal sacrum along the back to the neck and head. Diagnosis is most commonly made by vaginal examination during labor, when palpation of the distinct facial features of the mouth, nose, orbital ridges, and malar bones are encountered. This presentation may be confused with a breech presentation because the mouth may be confused with the anus, and the malar bones or orbital ridges may be confused with the fetal ischial tuberosities. Remember that the facial presentation has a triangular configuration of the mouth to the orbital ridges compared to the breech presentation of the anus and fetal genitalia. Diagnosis can ultimately be confirmed by ultrasound if any doubt remains. MECHANISM OF LABORSection 4 of 6
Intuitively, the cardinal movements of labor for a face presentation are not completely identical to those of a vertex presentation. Fetuses with face presentation probably initially begin labor in the brow position. While descending into the pelvis, the natural contractile forces combined with the maternal pelvic architecture allow the fetal head to either flex or extend. Following engagement in the face presentation, descent is made. This is followed by internal rotation and ultimately to flexion under the maternal symphysis. Using x-ray pelvimetry in a series of 7 patients, Borrell and Ferstrom demonstrated that internal rotation occurs between the ischial spines and the ischial tuberosities, lower than in the vertex presentation. Following internal rotation, the fetal mentum is below the maternal symphysis, and delivery occurs by flexion of the fetal neck. They also concluded that the presenting diameter is the trachelobregmatic. This diameter is larger than the usual suboccipitobregmatic that occurs in a vertex presentation. Engagement of the presenting part has not occurred until the face is at a +2 station because the distance from the leading edge to the largest presenting diameter is greater than in the vertex presentation. The above mechanisms of labor in the term infant can occur only if the mentum is anterior. If the mentum is posterior, the fetal neck is too short to span the length of the maternal sacrum and is already at the point of maximal extension. To deliver, the fetal shoulders must also enter the pelvis, although the head still cannot deliver because it cannot extend further through the symphysis. Fortunately, of infants with face presentation, the mentum is anterior in 60-80% of cases, the mentum is transverse in 10-12% of cases, and the mentum is posterior only 20-25% of the time. Fetuses with the transverse mentum usually rotate to the mentum anterior position, and 25-33% of posterior mentum fetuses rotate to an anterior mentum position. The indicated percentage of fetuses with a posterior mentum that rotate to anterior may be artificially low because surgical intervention may first be undertaken. LABOR MANAGEMENTSection 5 of 6
Labor management should follow that of a vertex management of labor. Duration of labor with a face presentation is generally the same as duration of labor with a vertex presentation, although a prolonged labor may occur in some cases. As long as no maternal or fetal compromise occurs, labor can continue. Continuous electronic fetal heart rate monitoring is considered mandatory by many authors because of the increased incidence of abnormal fetal heart rate patterns and/or fetal compromise. Careful application of the electrode must be ensured; the mentum is the recommended site of application. Facial edema is common and can obscure the fetal facial anatomy, making it important to assure proper placement. Oxytocin can be used to augment labor using the same precautions as in a vertex presentation and using the same criteria of assessment of uterine activity, adequacy of the pelvis, and reassuring fetal heart tracing. Perform cesarean delivery when arrest of labor occurs despite an adequate contraction pattern and/or with a nonreassuring fetal heart rate pattern. Fetuses with face presentation can be delivered vaginally with overall success rates of 60-70%, while 12-20% of fetuses with face presentation require cesarean delivery. Attempts to manually convert the face to vertex (Thom maneuver) or to rotate a posterior position to a more favorable anterior mentum position are rarely successful and are associated with high perinatal mortality and maternal morbidity. Internal podalic version and breech extraction are no longer recommended in the modern management of the face presentation. Forceps may be used if the mentum is anterior. Any typical forceps, including Kielland forceps, can be used. Although the landmarks are different, the application of any forceps is made as if the fetus were presenting directly in the occiput anterior position. The mouth substitutes for the posterior fontanelle, and the mentum substitutes for the occiput. Traction should be downward to maintain extension until the chin passes under the symphysis and then gradually elevated to allow the head to deliver by flexion. During delivery, careful attention must be taken to avoid hyperextension of the fetal head. Trauma during labor may cause tracheal and laryngeal edema immediately after delivery, which can result in neonatal respiratory distress. In addition, fetal anomalies or tumors, such as fetal goiters that may have contributed to fetal malpresentation, may make intubation difficult. Physicians with expertise in neonatal resuscitation should be present at delivery in the event that intubation is required. REFERENCESSection 6 of 6
Article Last Updated: Jun 18, 2007 |
