Chapter 27: Compound Presentations

PROLAPSE OF HAND AND ARM OR FOOT AND LEG

Definition

A presentation is compound when there is prolapse of one or more of the limbs along with the head or the breech, both entering the pelvis at the same time. Footling breech or shoulder presentations are not included in this group. Associated prolapse of the umbilical cord occurs in 15 to 20 percent of cases.

Incidence

Easily detectable compound presentations occur probably once in 500 to 1000 confinements. It is impossible to establish the exact incidence because:

1. Spontaneous correction occurs frequently, and examination late in labor cannot provide the diagnosis

2. Minor degrees of prolapse are detected only by early and careful vaginal examination

Classification of Compound Presentation

1. Cephalic presentation with prolapse of:

   1. Upper limb (arm–hand), one or both

   2. Lower limb (leg–foot), one or both

   3. Arm and leg together

2. Breech presentation with prolapse of the hand or arm

By far the most frequent combination is that of the head with the hand (Fig. 27-1) or arm. In contrast, the head–foot and breech–arm groups are uncommon, about equally so. Prolapse of both hand and foot alongside the head is rare. All combinations may be complicated by prolapse of the umbilical cord, which then becomes the major problem.

Etiology

The etiology of compound presentation includes all conditions that prevent complete filling and occlusion of the pelvic inlet by the presenting part. The most common causal factor is prematurity. Others include high presenting part with ruptured membranes, polyhydramnios, multiparity, a contracted pelvis, pelvic masses, and twins. It is also more common with inductions of labor involving floating presenting parts. Another predisposing factor is external cephalic version. During the process of external version, a fetal limb (commonly the hand–arm, but occasionally the foot) can become “trapped” before the fetal head and thus become the presenting part when labor ensues.

Diagnosis

Diagnosis is made by vaginal examination, and in many cases, the condition is not noted until labor is well advanced and the cervix is fully dilated.

The condition is suspected when:

1. There is delay of progress in the active phase of labor

2. Engagement fails to occur

3. The fetal head remains high and deviated from the midline during labor, especially after the membranes rupture

Prognosis

In the absence of complications and with conservative management, the results should be no worse than with other presentations.

Mechanism of Labor

The mechanism of labor is that of the main presenting part. Because the diameter ...