Leopold's Maneuvers

Leopold's maneuvers1 consist of an abdominal examination divided into four steps of palpation of the

gravid uterus and fetus (Fig. 1). The examiner may be able to palpate the presenting part. In addition,

a clinical estimate of the degree of engagement of the presenting part could be made, although the

final determination of engagement must be made by way of a vaginal examination. Through use of

Leopold's maneuvers, a clinical estimate of the fetal weight also can be obtained, although this is not a

formal part of this examination. The accuracy of Leopold's maneuvers can be hampered by the

maternal body habitus, the presence of uterine fibroids, multiple gestations, or polyhydramnios. What

follows is a description of these maneuvers:

Fig. 1. Leopold's maneuvers. The fetus is in a left occiput anterior position.(Pritchard JA, MacDonald PC: William's Obstetrics, 16th ed. New York,

Appleton-Century-Crofts, 1980)

Maneuver I: The uterine contour is outlined. The fundus is palpated with the fingertips of both hands

facing toward the maternal xiphoid cartilage. This should allow the identification of the fetal parts in

the upper pole (fundus) of the uterus.

Maneuver II: Once an assessment is made of the fetal part present in the uterine fundus, the hands are

placed at either side of the maternal abdomen. With this maneuver, the examiner will be able to

determine the location of the fetal back.

Maneuver III: Using one hand, the examiner will grasp the presenting part between the thumb and

fingers. This is done on the lower abdomen, a few centimeters above the symphysis pubis. This will

allow the examiner to develop a further identification of the presenting part and assessment of its

engagement.

Maneuver IV: This last maneuver resembles the first one, but instead of facing the fundus, the

examiner faces the pelvis of the patient. The palms of both hands are placed on either side of the

lower maternal abdomen, with the fingertips facing toward the pelvic inlet. This maneuver should allow

the identification of the fetal parts in the lower pole of the uterus.

After the abdominal examination, a digital vaginal examination is performed. The status of the

amniotic membranes and the degree of engagement of the presenting part are indicators of fetal

presentation and position. The vaginal examination also allows the clinician to assess the degree of

cervical dilation and effacement. If the presenting part is not easily palpable, it is important that

further assessment be obtained by performing an ultrasound examination. The ultrasound should be

100% accurate in diagnosing the type of fetal presentation.

Fetal Lie

Using the techniques described above, the clinician should be able to develop an assessment of the

relationship between the fetal and maternal dorsal columns (the longitudinal axis of the human body).

If the fetus and maternal column are parallel (on the same long axis), the lie is termed vertical

or longitudinal lie. This is the most common lie of fetuses in labor. Contrary to this is the transverse lie,

in which the fetus is positioned 90° with respect to the mother's dorsal column. There are variants of

these two lies, in which the fetus may be in transition from a vertical to a transverse lie. These are

the oblique lies.

A fetus can be in an unstable or variable lie when the head is completely unengaged and floating. This

situation is seen mostly in cases of severe polyhydramnios and prematurity. The obstetrician should be

aware that a fetus in this particular type of lie is susceptible to a cord accident if the patient is in active

labor and her cervix is dilating.

Attitude

In addition to having a lie, the fetus has an attitude. This is defined as the relation of the various parts

of the fetus to each other. In the normal attitude, the fetus is in universal flexion. The anatomic

explanation for this posture is that it enables the fetus to occupy the least amount of space in the

intrauterine cavity. The fetal attitude is extremely difficult, if not impossible, to assess without the help

of an ultrasound examination.

Presentation

After the lie of the fetus is assessed, the clinician has to detail the fetus further by describing the

lowermost structure of the fetus in the maternal pelvis. This is referred to as the fetal presentation. In

a vertical (or longitudinal) lie, the fetal presentation can be eithercephalic or breech. In the transverse

lie, the presentation is usually the back or shoulder; in the oblique lie, it is usually the shoulder or the

arm.

The cephalic presentation can be further categorized based on the degree of flexion of the fetal head:

A well-flexed head is described as a vertex presentation, an incomplete flexion as a sinciput

presentation, a partially extended (deflexed) head as a brow presentation, and a complete extension

of the head as a face presentation.

Breech presentation can be categorized on the basis of the attitude or flexion of the hip and knee

joints. If there is flexion at the hip and extension at the knees, the fetus is afrank breech. If there is

flexion at both the hip and knee joints, the fetus is a full orcomplete breech. A footling breech has one

or both hips and knees in a partial or intermediate extension; this fetus is sometimes called

an incomplete breech.

Presentations other than cephalic or breech in a singleton pregnancy require an abdominal route of

delivery. These presentations are uncommon, occurring in less than 1% to 2% of all deliveries.

Abnormal presentations occur more often in cases of multiple gestation, usually affecting the second

twin. Depending on the clinical condition, vaginal delivery of a malpresenting second twin is possible.

Position

The next step in the assessment of the fetus consists of determining the position of the presenting

part. This is a description of the relation of the presenting part of the fetus to the maternal pelvis.

In the case of a longitudinal lie with a vertex presentation, the occiput of the fetal calvarium is the

landmark used to describe the position. When the occiput is facing the maternal pubic symphysis, the

position is termed direct occiput anterior. If the occiput is between the ischial spines and the

symphysis, it is called either a right or left occiput anterior. If the occiput is located halfway between

the promontorium of the sacrum and the symphysis, the position is termed either a left or right occiput

transverse. As the occiput approaches the sacrum, it becomes either a right or left occiput

posterior. When the occiput is straight down (i.e., facing the sacrum or coccyx), the position is

called direct occiput posterior. This method of describing the fetal position can be applied to other

presentations by substitution of the vertex for the presenting fetal anatomic landmark. In cases of

breech presentation, the fetal sacrum is used for position.

With transverse and oblique lies, the shoulder structures (acromion) can be used for the description of

position. The incidence of transverse lie has been reported as 0.3%.2 Fetal malformations can cause

these (and other) malpresentations. These two types of lies have been associated with grandparity,

contracted maternal pelvis, placenta previa, prematurity, polyhydramnios, and uterine abnormalities

such as transverse septum or leiomyomas. A patient in her last month of pregnancy with a fetus in a

transverse or oblique lie would require an ultrasound and physical examination for the evaluation of

any of the above risk factors. If no contraindications are identified, one possible management

alternative would be an external cephalic version. The success of external cephalic version in cases of

transverse lie has been reported as high as 83%,3 even when performed intrapartum. If an elective

cesarean section is to be performed, it should be scheduled for the last week of the pregnancy,

because 83% of transverse lies will spontaneously convert to a vertex presentation before 39

weeks.4 This expectant management has to be individualized. Patients showing signs of early labor or

those with cervical dilation are candidates for an attempt of external version or delivery by cesarean

section before 39 weeks.

The fetal anatomic landmarks used to describe the position in the brow and face presentations are

the bregma and the mentum. The outlook of the persistent brow presentation for vaginal delivery is

poor. Approximately two thirds of brow presentations will convert to vertex or face.2 Fortunately, this is

a rare presentation, with an incidence of only 0.05%.5 If the presentation persists as a brow, a

cesarean section should be performed. The incidence of face presentation has been quoted as 0.21%

of all deliveries.6In cases of face presentation, a vaginal delivery can be accomplished most frequently

with a mentum anterior position, but the mentum posterior position will impede the fifth cardinal

movement of labor (extension). Most fetuses in face or mentum posterior position that do deliver

vaginally do so after converting during the internal rotation into a mentum anterior ormentum

transverse position.

A fetus in a persistent mentum posterior position could be delivered vaginally if it were very premature

or the maternal pelvis large. Most frequently, this will not be the case. More than 75% of fetuses at

term with mentum posterior position will require delivery by cesarean section because of labor

dystocia. This contrasts with a more than 88% success rate of vaginal delivery with the mentum

anterior position.7 In view of these data, many clinicians opt to perform a cesarean section for fetuses

with a face presentation and a mentum posterior position, without allowing for a trial of labor. Even if

vaginal delivery of a mentum anterior presentation is attempted, the diameter of the presenting part

may exceed the maternal pelvic capacity. A situation like this also would require an abdominal

delivery. Before allowing vaginal delivery of a fetus in a face presentation and a mentum anterior

position, the clinician should exclude the possibility of a fetal malformation causing the

malpresentation. The brow and face presentation should alert the clinician to the possibility of a

congenital fetal anomaly, such as thyromegaly, cystic hygroma, anencephaly, encephalocele, cervical

neural tube defects, and teratomas, that could be preventing the flexion of the head. In addition,

maternal factors, such as preterm labor, abnormal pelvis, multiple gestation, and a low-lying placenta,

have been associated with deflexion of the fetal head. After excluding the possibility of a fetal

malformation with the use of a detailed ultrasound examination, the clinician should then exclude the

possibility of a contracted maternal pelvis. If on clinical pelvimetry there are any signs of an abnormal

pelvis, the clinician should consider obtaining an x-ray or digital pelvimetry.

In addition to the above presentations and fetal positions, there are compound presentations in which

one or more extremities of the fetus will present in addition to the vertex or breech. This has been

described as “prolapse of an extremity alongside of the presenting part, both entering the pelvic canal

simultaneously.”8 The incidence of this type of presentation has been reported to range from 0.15%9 to

0.4%.10 The most frequent is a vertex and hand combination, which accounts for 58% of the

cases.9 This is followed in incidence by a vertex, hand, and umbilical cord combination (17%). It is

extremely important that the clinician exclude the presence of an umbilical cord prolapse when

evaluating a patient with a compound presentation. Risk factors for this type of presentation include

contracted maternal pelvis, preterm labor, small for gestational age fetuses, and grandparity. The

majority of women whose fetuses have compound presentations can be delivered vaginally. In a series

of 131 patients,10 only 2 required a cesarean section. During the course of labor, the extremity will

usually slide to the side of the body and the compound presentation will spontaneously convert to a

vertex presentation.

Station

In addition to the fetal lie, presentation, and position, the level or station of the presenting part in the

maternal pelvis is an important factor in the labor process. For this assessment, the ischial tuberosities

of the maternal pelvis are used as the anatomic landmark structures. If the presenting part is above

the spines, it is described by the use of negative numbers. If the presenting part is nonpalpable, it is in

a floating station; if it is well applied against the cervix, but above the spines, it can range from -1 to -

3. There is a significant subjective variation among examiners in the assignment of station. Some

consider these numbers to be equivalent to centimeters. Once a presenting part is at the level of the

spines, it is considered to be engaged and at 0 station. Below the 0 station, positive numbers are used.

If the presenting part is against the pelvic floor, it is at +3 station.

Cardinal Movements of Labor

To accommodate itself to the maternal pelvic dimensions, the fetus must undergo a series of changes

in the attitude of its presenting part. This is required for fetal descent through the birth canal. The

cardinal movements of labor in a vertex presentation are as follows:

1. Engagement: The vertex is engaged when the biparietal diameter is at the level of the pelvic

inlet or lower. In clinical practice, this translates into an occiput palpable at 0 station.

2. Descent: This cardinal movement will usually happen concomitant with engagement, and is

typically documented late in the active phase of the first stage of labor.

3. Flexion: As the vertex descends into the maternal pelvis, it will encounter resistance from the

maternal pelvic floor muscles. This will cause the flexion of the fetal head onto the thorax.

4. Internal rotation: At the moment of engagement and descent of the vertex into the pelvis, the

fetus will be in a transverse position. Because of the anatomic configuration of the

pubococcygeus and iliococcygeus muscles, the occiput will be forced to rotate to the symphysis

pubis. This is the widest area of the pelvic floor that will allow the passage of the fetus.

5. Extension: At the moment of the delivery of the fetal head, the combined effects of the uterine

contractions and the pelvic floor result in this cardinal movement.

6. External rotation: This movement occurs as a consequence of the alignment of the head of the

fetus with its spine as the pressure from the maternal pelvis and muscles on the fetal head is

alleviated.

7. Expulsion: After delivery of the head, the anterior shoulder will descend under the pubic bone. As

it is delivered, it will follow the external rotation of the head of the fetus.

It is important for the reader to understand that these are not separate events. They are all closely

related, and some will happen simultaneously.

Concomitant to the cardinal movements, there can be significant molding of the presenting part. This

complex process can be deeply influenced by a large number of factors. Abnormalities of the shape

and size of the presenting part or maternal pelvis can cause problems affecting not only the capacity

of the fetus to descend, but also its internal rotation. Most fetuses initiate the cardinal movements in a

occiput transverse position. If its internal rotation were to be disrupted, the fetus could present in an

occiput posterior position. Internal rotation can be affected by the administration of epidural

anesthesia. If the pelvic floor musculature is suddenly relaxed by a strong epidural block, internal

rotation could be directed toward the maternal sacrum, rather than toward the symphysis. In addition,

the head of the fetus could become asynclitic. This condition occurs when the head is not in the same

longitudinal axis as the fetal vertebral column. The gross appearance of an asynclitic head is that of a

lateral tilt toward the shoulder. The major problem of asynclitism is that it causes the head to present

a larger diameter to the maternal pelvis than what it would otherwise present. This could lead to labor

dystocia due to a relative cephalopelvic disproportion.

Additional problems related to the sudden relaxation of the pelvic floor muscles include possible lack

of flexion of the presenting part. In a fetus in a vertex lie, this could result in a brow or face

presentation.

Other factors that could influence the position of the presenting part include the maternal position

during labor, the presence of fetal or uterine anomalies, and the type of maternal pelvis. In Western

society, it has been a common practice for women to labor on their back or side. Midwives frequently

have their patients labor in positions other than the back or side so that the occiput on posterior

position is prevented, although this practice has not been studied objectively.

THE MATERNAL PELVIS AND ITS VARIATIONS

The shape and size of the maternal pelvis has been the subject of significant evaluation and

description. Most of current knowledge on this subject originates from the classic contributions of

Caldwell, Moloy, and D'Esopo.11,12 The clinical recognition of the different types of pelves is important

because of their different capacity, obstetric significance, and resulting prognostic importance.13

The four major types of maternal pelves and their characteristics are outlined as follows:

I. Gynecoid (Fig. 2)

Fig. 2. Gynecoid pelvis. A. Inlet view. B. Lateral view. C. Subpubic arch view.

A. A spacious and well-rounded posterior segment

B. A An inlet with a slightly ovoid or round shape

C. A wide, well-rounded forepelvis (anterior segment)

D. A sacrosciatic notch of medium size

E. An average sacral inclination and curvature

F. A wide subpubic arch

G. Wide interspinous and intertuberous diameters

H. Bones ranging from medium to delicate in structure

Engagement in this type of pelvis occurs most frequently with the fetus in a transverse

position, followed in frequency by the anterior and posterior positions.

II. Android (Fig. 3)

Fig. 3. Android pelvis. A. Inlet view. B. Lateral view. C. Subpubic arch view.

A. A wedge-shaped inlet

B. A narrow retropubic angle (anterior segment)

C. A flat, wide posterior segment

D. A narrow sacrosciatic notch

E. A forward sacral inclination

F. A narrow wedge-shaped “Gothic” subpubic arch

G. Converging side walls, narrow interspinous and intertuberous diameters

H. Bones ranging from medium to heavy in structure

Engagement in this type of pelvis occurs most frequently with the fetus in a transverse

position, followed in frequency by the posterior and anterior positions. The clinician should

be alerted by this type of pelvis that the possibility of posterior positions exists.

III. Anthropoid (Fig. 4)

Fig. 4. Anthropoid pelvis. A. Inlet view. B. Lateral view. C. Subpubic arch view.

A. A long, narrow, oval-shaped inlet

B. A long, narrow, well-rounded anterior segment

C. A long, narrow posterior segment

D. A very wide, shallow sacrosciatic notch

E. A long, narrow sacrum with average inclination and curvature

F. A slightly narrow subpubic arch

G. Straight side walls with below-average interspinous and intertuberous diameters

H. Medium to delicate bones

Engagement in this type of pelvis occurs with the fetus in either an anterior or transverse

position, but the anterior position appears to be more characteristic.

IV. Platypelloid (Fig. 5)

Fig. 5. Platypelloid pelvis. A. Inlet view. B. Lateral view. C.Subpubic arch view.

A. A transverse, oval-shaped inlet

B. A very wide, round retropubic angle

C. A very wide, flat posterior segment

D. A narrow sacrosciatic notch

E. Average sacral inclination

F. A very wide subpubic arch

G. Straight side walls with very wide interspinous and intertuberous diameters

H. Bones ranging from medium to delicate in structure

Engagement in this type of pelvis will almost always occur with the fetus in a transverse position.

Because of the flatness of the shape of this pelvis, the internal rotation of the vertex can be limited,

causing a deep transverse arrest.

The most frequently encountered type of pelvis is the gynecoid, followed by the android, anthropoid,

and platypelloid.