Compound presentation is defined as presentation of a fetal extremity alongside the presenting part. It may involve one or more extremities (eg, hand, arm, foot) with the vertex or the breech. The majority of compound presentations are represented by the fetal hand or arm presenting with the vertex .
INCIDENCE AND ETIOLOGY
Compound presentation complicates from 1 in 700 to 1 in 1000 deliveries [2,3]. It is more likely to occur when the pelvis is not fully occupied by the fetus because of low birth weight, multiple gestation, polyhydramnios, or a large pelvis [2,4]. Rupture of membranes when the presenting part is still high also increases the risk of compound presentation, cord prolapse, or both. Another predisposing factor is external cephalic version [4,5]. During the process of external version, a fetal limb (commonly the hand/arm, but occasionally the foot) can become "trapped" below the fetal head and thus become the presenting part when labor ensues. In multiple gestations, a possible scenario involves the head of the first twin and an extremity of the second twin within the birth canal.
Compound presentation may be noted on an antepartum obstetrical ultrasound examination or palpated during a cervical examination, typically during early labor. The examiner will feel an irregular shape beside or in advance of the vertex or breech. Compound presentation may not be diagnosed on admission to the labor unit if the cervix is long or closed, but will be discovered as labor progresses and the cervix becomes more dilated. The clinician should consider this condition when the head remains high or unengaged after rupture of membranes or when there is a delay in the active phase.
The management of compound presentation is debatable. Some experts recommend attempting to reposition the fetal extremity, while others discourage this practice . There is consensus that oxytocin should be avoided.
For women with normal progressing labor, we favor observation alone. Occasionally, the presenting part will simply push the extremity aside or the fetus will retract the extremity as labor progresses.