INTRODUCTION — Compound presentation is a fetal presentation in which an extremity presents alongside the part of the fetus closest to the birth canal. The majority of compound presentations consist of a fetal hand or arm presenting with the head [1]. This topic will review the pathogenesis, clinical manifestations, diagnosis, and management of this uncommon intrapartum problem.

INCIDENCE — Compound presentation has been reported to complicate from 1 in 250 to 1 in 1500 deliveries [2-5]. This is a crude and wide estimate because transient cases are not consistently recognized, documented, or reported.

PATHOGENESIS AND RISK FACTORS — A variety of clinical settings can lead to compound presentation via different pathways. Compound presentation may occur when:

●The fetus does not fully occupy the pelvis due to early gestational age, multiple gestation, polyhydramnios, or a large maternal pelvis relative to fetal size, thus allowing a fetal extremity room to prolapse [2,3].

●Rupture of membranes occurs while the presenting part is still high, which allows flow of amniotic fluid to carry a fetal extremity, umbilical cord, or both toward the birth canal.

●During external version, a fetal limb (commonly the hand/arm, but occasionally the foot) becomes "trapped" below the fetal head and thus becomes the presenting part when labor ensues [6-8].

●The head of the first twin and an extremity of the second twin present together within the birth canal, but this is rare.

CONSEQUENCES — The large irregular presenting part of a compound presentation can result in:

●Dystocia.

●Cord prolapse, which was reported in 15 and 23 percent of patients in two series [2,9].

CLINICAL PRESENTATION

●Antepartum, compound presentation may present as an incidental finding on ultrasound examination.

●Antepartum or intrapartum, an irregular shape beside or in advance of the head or breech may be detected on a routine digital cervical examination, unless the cervix is long and closed.

●Intrapartum, protraction or arrest may occur in the active phase.

The head may remain persistently unengaged after rupture of membranes, and the unengaged fetal head may be deviated from the midline [9].

In the second stage, arrest of descent may be associated with a variant of compound presentation in which the fetal hand fills the space between the head and the maternal sacrum [10].

DIAGNOSIS — The diagnosis of compound presentation is based on identification of one or more fetal extremities presenting alongside or in front of the head or buttocks on physical or ultrasound examination.

Differential diagnosis — Differential diagnosis of the physical examination finding of fetal extremity as the presenting part includes:

●Compound presentation

●Transverse lie with prolapse of an extremity

●Footling breech presentation

An accurate diagnosis is easily made by ultrasound examination or more thorough abdominal and vaginal examinations.

MANAGEMENT

Antepartum management — Antepartum identification of compound presentation usually does not require any interventions or monitoring.

If noted on ultrasound examination immediately following an otherwise successful external cephalic version, the compound presentation will usually resolve spontaneously. In this setting, if a foot or hand is preventing the head from settling into the inlet, we have found vibroacoustic stimulation useful in prompting fetal movement sufficient to resolve the problem.

If a compound presentation is identified on ultrasound examination in a patient with polyhydramnios, the patient should be counseled on the risks of a prolapsed umbilical cord and fetal extremity when membranes rupture. (See "Umbilical cord prolapse", section on 'Anticipation and prevention of cord prolapse'.)

Intrapartum management — Approaches to intrapartum management of compound presentation are based on patient-specific factors, clinical experience, and insights from case reports and small series, given the infrequent occurrence of this problem. High-quality data to guide management are not available.

For patients with normally progressing labor, we favor observation alone. Some authorities suggest attempting to gently reposition the fetal extremity, while others discourage this practice [3-5,9,11]. We favor expectant management because sometimes the presenting part will simply push the extremity aside or the fetus will retract the extremity as labor progresses, and a large majority of compound presentations will deliver vaginally. A compound presentation involving the arm is more likely to resolve than one involving the foot [4]. We choose not to pinch the presenting part in an attempt to provoke the fetus into withdrawing the presenting part, although this practice is not likely to be harmful.

If the compound presentation persists, descent of the presenting part could be protracted or arrested, unless the fetus is extremely small. Therefore, if descent becomes protracted or arrested in the second stage, manipulation may be considered. The author gently pushes the small part up into the uterine cavity with his dominant hand while simultaneously applying gentle fundal pressure to effect descent of the head with the other hand. If this gentle maneuver does not resolve the compound presentation and abnormal progress of labor, the author has a low threshold for proceeding to cesarean birth because of the increased risk for obstructed labor and an adverse outcome (see 'Outcome' below). Oxytocin augmentation should be avoided as it may lead to uterine rupture [2,7]. Operative vaginal delivery should generally be avoided in a recognized compound presentation.

OUTCOME — In most cases of compound presentation managed by contemporary standards, labor results in an uncomplicated vaginal delivery. Historically, however, high mortality rates were reported and were related to prolonged obstructed labor, internal podalic version and extraction, uterine rupture, prolapsed cord, and complications of preterm birth.

No large contemporary series of compound presentation have been published. The following case reports, and others, underscore the need for cesarean delivery if the compound presentation does not resolve spontaneously or with gentle pressure in cases of protracted labor. However, it should be noted that case reports generally describe complicated cases [12-14].

●A case report of a patient with a compound presentation and protracted labor described entrapment of the fetal arm between the head and bony pelvis, which may have been the cause of ischemic necrosis of the arm; limb amputation was required [12].

●Another case report described a similar occurrence with a dramatic appearance of limb ischemia (picture 1), but recovery occurred without the need for amputation [14].

●A third case report described a vacuum-assisted delivery in which an unrecognized compound presentation resulted in a rectal laceration; the fetal hand was found to be protruding through the anus as the head was crowning [13].

If neonatal compartment syndrome occurs, some authorities recommend urgent fasciotomy, which may salvage the limb. (See "Pathophysiology, classification, and causes of acute extremity compartment syndrome", section on 'Birth injury'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Labor".)

SUMMARY AND RECOMMENDATIONS

●Compound presentation (ie, presentation of an extremity alongside the part of the fetus closest to the birth canal) is rare. Predisposing factors include prematurity, multiple gestation, polyhydramnios, a large pelvis, external cephalic version, and rupture of membranes at high station. (See 'Incidence' above and 'Pathogenesis and risk factors' above.)

●A compound presentation may present as an incidental finding on ultrasound examination or it may be palpated as an irregular shape beside or in advance of the vertex or breech during a cervical examination. (See 'Clinical presentation' above and 'Diagnosis' above.)

●Antepartum identification of compound presentation usually does not require any interventions or monitoring other than patient education about the finding. (See 'Antepartum management' above.)

●For compound presentations with normal progress of labor, we suggest expectant management rather than intervention (Grade 2C). Most cases will resolve spontaneously or will have vaginal births even without resolution. (See 'Intrapartum management' above.)

●A persistent compound presentation can result in dystocia. If descent of the presenting part in the second stage becomes protracted or arrests, we gently push the small part up into the uterine cavity with the dominant hand while simultaneously applying fundal pressure with the other hand to effect descent of the vertex. If the compound presentation and labor abnormality do not resolve after this gentle maneuver, we have a low threshold for proceeding to cesarean delivery. Oxytocin augmentation should be avoided as it may lead to uterine rupture. (See 'Intrapartum management' above.)

ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Edward R Yeomans, MD, and Clint M Cormier, MD, who contributed to earlier versions of this topic review.