Compound Presentations- Causes, Effects on Labor, Complications, and Management

What Are Compound Presentations?

Compound presentations are rare obstetric occurrences that frequently cause the care team to become quite anxious. A prenatal presentation known as a compound presentation occurs when one extremity develops concurrently with the part of the fetus that is closest to the birth canal. A fetal hand or arm typically presents with the head during compound presentations.

A presentation is considered compound when one or more limbs prolapse together with the head or breech, both of which enter the pelvis simultaneously. This group excludes footling breech or shoulder presentations. In 15 % to 20 % of instances, the umbilical cord prolapses along with the condition.

Compound Presentations Are Classified As,

1. Cephalic presentation with prolapse of,

   • One or both upper limbs (arm and hand).

   • One or both lower limbs (leg and foot).

   • Arms together with legs.

2. Breech presentation accompanied by an arm or hand prolapse.

The head with the hand or arm combination is by far the most common. On the other hand, the head-foot and breech-arm groups are relatively infrequent. It is unusual for a hand or foot to prolapse alongside the head. The prolapse of the umbilical cord might complicate any combination, which makes it the main issue.

What Causes Compound Presentations?

Different mechanisms can result in compound presentation from several clinical contexts. The causes of compound presentations include any circumstances that prevent the presenting component from completely filling and occluding the pelvic entrance.

Instances of compound presentation include,

• Due to early gestational age, multiple gestations, polyhydramnios (excessive amniotic fluid accumulation), or a large maternal pelvis in comparison to fetal size, the fetus does not fully occupy the pelvis, which leaves an opportunity for a fetal extremity to prolapse.

• When the presenting part is still high, the membranes rupture, allowing the amniotic fluid to flow and carry a fetal extremity, the umbilical cord, or both to the birth canal.

• Preterm labor.

• External Cephalic Version (ECV)- A fetal limb (often the hand or arm, but occasionally the foot) may become "trapped" before the fetal head during the external version process and end up being the component that gives birth when labor starts.

How Are Compound Presentations Diagnosed?

A vaginal examination is used to make the diagnosis, and in many cases, the problem is not discovered until labor has progressed significantly and the cervix is fully dilated.

One suspects the condition when,

• The active phase of labor is moving more slowly than it should.

• Engagement does not take place- In any situation where the fetal head does not engage during labor, but there is no cephalo-pelvic disproportion, the compound presentation diagnosis should be considered.

• Even after the membranes have ruptured, the fetal head continues to be elevated and off-center during labor.

What Is the Effect of Compound Presentation on Labor?

The size of the fetus and the size of the mother's pelvis affect how compound presentation affects labor.

There are three possible perspectives on this,

1. The fetal head may not enter the pelvic brim in cases where the fetus is large and the pelvis is narrow due to a compound presentation. If it is not fixed, it will cause obstructed labor.

2. A complex presentation will delay the second stage of labor when the fetus and the pelvis are of average size. This delay results from the prolapsed limb interfering with the fetal head's normal internal and external flexion and rotation mechanisms. Correction is frequently required.

3. A complex presentation will not change the course of labor if the fetus is small and the pelvis is large; the baby will still be born with the hand prolapsed.

What Are the Complications of Compound Presentation?

The two complications likely to occur are prolapse of the umbilical cord and uterine inertia.

They are as follows,

• Prolapse of the Umbilical Cord- The same factors that lead to limb prolapse can cause cord prolapse. Most of the time, it will call for immediate delivery.

• Inertia- Inertia may complicate any malpresentation. Its exact cause is unknown, but it may be due to the malposition of the fetus interfering with the normal mechanism of labor. The uterus reacts to this interference by diminishing its action. Treatment of inertia usually first necessitates replacement of the prolapsed limb, except early in the first stage, when it is sometimes better to treat inertia by recognized methods and later replace the limb.

What Is the Treatment and Management of Compound Presentation?

As in all cases of malpresentation, the first essential is to determine whether the pelvis is large enough to allow vaginal delivery. A cesarean section will have to be performed if there is a mechanical obstruction.

If there is no obstruction, a vaginal delivery will be possible following one of the undermentioned methods,

• Treatment of the presentation of an arm aims at preventing its prolapse into the vagina when the membranes rupture. Initially, the patient is placed in the genupectoral or high Trendelenburg position for 30 minutes. This allows the limb, aided by gravity, to slip back above the head. The patient is then placed in the dorsal position. The fetal head is pushed into the pelvic brim by abdominal palpation, and an abdominal binder is applied. This method is not always successful. A vaginal examination should be performed as soon as the membranes rupture.

• The prolapse of an arm or foot is best treated by replacing the limb above the head. The head is then pressed down by pressure on the abdomen. It is advisable not to remove the hand from the vagina until the head has been pushed into the pelvis.

• When a prolapsed arm is discovered during the second stage of labor, it is sometimes possible to deliver by forceps without replacing the arm. During the application of the forceps, care must be taken not to include the arm within the forceps blades.

• The internal version is now rarely used because of the dangers involved. The method may cause separation of the placenta and death of the features, rupture of the uterus, and probable death of the mother.

This method should only be used in the following cases,

• An arm prolapses again after replacement.

• A foot resists all attempts at replacement.

• Occasionally when the compound presentation is complicated by prolapse of the cord.

Prolapse of the cord necessitates rapid treatment if the fetus is to be saved. In the first stage of labor, a cesarean section is the treatment of choice. During the second stage of labor, forceps delivery is indicated, preferably if conditions permit, without replacement of the limb. The internal version is indicated solely when these procedures are not practical because of a lack of equipment.

Conclusion:

In the majority of situations, compound presentation events need not significantly alter the arrangements already made for the method of managing the birth process. Simple stimuli that are intended to encourage the baby to reject the abnormal component may be successful. Following the identification of the invasive portion, labor and delivery should be managed conservatively and in accordance with other established obstetrical standards.