Problems with Fetal Position, Presentation, Size, & Passage

Occipitoposterior Position

The usual fetal position is posterior rather than anterior.
Assuming that the presentation is vertex, the occiput is directed diagonally and posteriorly, either to the left or to the right.
During internal rotation in these positions, the fetal head must rotate through an arc of approximately 135 degrees.
Rotations from a posterior position can be aided by having the woman assume a hands and knees position, squatting or lying on her side; however, this is tiring for women in labor.
Posterior positions usually occur in women with android, anthropoid, and contracted pelvis.
Posterior positions happen in dysfunctional labor pattern such as prolonged active phase, arrested descent, or fetal heart sounds heard best at lateral sides of the abdomen.
A head in posterior position does not fit the cervix like a head in anterior position does.
This can be confirmed through vaginal examination or through ultrasound because it might cause umbilical cord prolapse.
Labor is prolonged because the arc of rotation is greater.
Pressure and pain would be experienced by the woman in her lower back owing to sacral nerve compression when the fetal head rotates against the sacrum.
To relieve a portion of the pain, applying counterpressure on the sacrum by a back rub may be done, and heat or cold application can also help.
To help the fetus rotate, the woman may lie on the side opposite the fetal back or assume a hands and knees position.
The woman should void every 2 hours to keep her bladder empty and avoid impeding the descent of the fetus.
The woman may also need an oral sports drink or IV glucose solution to replace glucose stores used for energy.
Maternal exhaustion can cause uterine dysfunction, so a rotation of 135 degrees may not be possible if the contractions are ineffective or if the fetus is larger than average.
The fetal head might arrest in the transverse position or there might be no rotation at all, so cesarean birth would be necessary.
Provide reassurances to the woman that even though her labor is not “by the book” it is still within safe and controlled limits.

Oversized Fetus

Macrosomia or an oversized fetus weighs more than 4000 to 4500g, and this size may become a problem.
Macrosomic babies are usually born to women with diabetes or develop gestational diabetes, and multiparas.
Uterine dysfunction might result from an oversized fetus because of the overstretching of the fibers of the myometrium.
The wide shoulders pose a problem at birth because it can cause fetal-pelvic disproportion or uterine rupture from obstruction.
Cesarean birth is necessary if the fetus is so oversized to be born vaginally.
To compare the size of the fetus with the woman’s pelvic capacity, pelvimetry or ultrasound can be performed.
If a macrosomic baby is born vaginally, there are high risks for cervical nerve palsy, diaphragmatic injury, or fractured clavicle due to shoulder dystocia.
The woman is at risk for over because of the overdistended uterus and uterine atony.

Shoulder Dystocia

Shoulder dystocia occurs during the second stage of labor when the fetal head is born but the shoulders are too broad to enter and be born through the pelvic outlet.
The woman is at risk for vaginal and cervical tears, while the fetus is at risk for cord compression between the fetal body and the bony pelvis.
If birth is forced through the vaginal opening, the fetus would sustain a fractured clavicle or a brachial plexus injury.
Shoulder dystocia usually occurs in women who have diabetes, in multiparas, and in post-date pregnancies.
Shoulder dystocia is discovered often during the birth of the head and the shoulders lock beneath the symphysis pubis.
Other conditions that may suggest shoulder dystocia are prolonged second stage of labor, arrest of descent, or when the head starts to crown, it retracts instead of protruding with each contraction.
Instruct the woman to flex her thighs sharply on her abdomen (McRobert’s maneuver) to widen the pelvic outlet and allow the anterior shoulder to be born.
Applying suprapubic pressure can also help the shoulder out from beneath the symphysis pubis.

Breech Presentation

Most fetuses are in a breech presentation early in pregnancies; however, by week 38, it turns into a cephalic presentation.
The fetal head may be the widest single diameter but the fetus’ buttocks and legs take up more space.
The fetus turns into cephalic position mostly because the fundus is the largest part of the uterus, so the buttocks and the lower extremities are in the fundus.
Types of breech presentation include complete, frank, and footling.
Breech presentation increases the fetal risk for anoxia, traumatic injury to the head, fracture of the spine or arm, dysfunctional labor, and early rupture of membranes.
Meconium present in the amniotic fluid is a sign buttock pressure, and this can lead to meconium aspiration once the infant inhales amniotic fluid.
Fetal heart sounds are heard high in the abdomen in breech presentation.
Leopold’s maneuver and vaginal examination can determine breech presentation.
Be certain to monitor the FHR and uterine contractions continuously to detect fetal distress early and provide prompt intervention.
In a breech birth, the birth of the head is the most dangerous part because a loop of umbilical cord that has passed down alongside the head may be compressed.
Intracranial hemorrhage is another danger of breech birth because of the pressure changes that has occurred spontaneously.
An infant born from a frank breech position usually extends his or her legs continuously during the first 2 or 3 days of life, so be sure to point out to the parents that this is normal.

Face Presentation

Face and brow presentations are called asynclitism or a fetal head presenting at a different angle than expected.
In face presentation, the head diameter the fetus presents to the pelvis is often too large for birth to proceed.
The back would be difficult to outline because it is concave.
Face presentation can be determined through vaginal examination when the nose, mouth, or chin is felt as the presenting part or through ultrasound.
Face presentation usually occurs in women with contracted pelvis, or placenta previa, in a relaxed uterus of a multipara, with prematurity, hydramnios, or fetal malformation.
If the chin is anterior and the pelvic diameters are within normal limits, the infant can be born vaginally.
If the chin is posterior, cesarean birth is the birth method of choice.
Facial edema and ecchymosis are present in a baby born after a face presentation.
Assess the patency of the infant’s airway closely.
Reassure the parents that the edema is transient and will disappear after a few days.

Brow Presentation

The rarest among the presentations is the brow presentation.
This presentation usually occurs in multipara women or in a woman with relaxed abdominal muscles.
Obstructed labor occurs because the head becomes jammed in the brim of the pelvis as the occipitomental diameter presents.
Cesarean birth would be necessary unless the presentation spontaneously corrects itself.
Extreme ecchymosis on the face is also present in infants born after a brow presentation.
Reassure the parents that the bruising over the same area as the anterior fontanelle is normal.

Inlet Contraction

Inlet contraction is the narrowing of the anteroposterior diameter to less than 11 cm or the transverse diameter to 12 cm or less.
The usual cause is rickets in early life or by an inherited small pelvis.
If the fetal head engages during the 36th to 38^th week of pregnancy, then the pelvic inlet is adequate.
If there is no engagement in primigravidas, then either a fetal abnormality or a pelvic abnormality should be suspected.
Every primigravida should have pelvic measurements taken and recorded before week 24 of pregnancy so that a birth decision can be made.
In CPD, the fetus remains in a floating position that could further complicate the already difficult situation.
If the membranes rupture, then the risk for cord prolapse increases greatly.

Outlet Contraction

Outlet contraction is the narrowing of the transverse diameter at the outlet to less than 11 cm.
This is the distance between the ischial tuberosities, a measurement that is easy to make during a prenatal visit, so the narrow diameter can be anticipated before labor starts.
This can also be assessed easily during labor.

Trial Labor

Trial labor refers to determination of the progress of labor in a woman who has borderline inlet measurement with a good fetal lie and position.
Trial labor may continue as long as descent of the presenting part and dilatation of the cervix continue to occur.
Monitor fetal heart sounds and uterine contractions continuously.
Instruct the woman to void every 2 hours to aid in fetal descent.
After the rupture of membranes, assess the FHR closely; if the fetal head is still high, there is an increased danger of prolapsed cord and anoxia in the fetus.
Cesarean birth would be necessary if there is no progress in labor after 6 to 12 hours.
If trial labor fails and cesarean birth is scheduled, provide an explanation about why cesarean birth is the best birth method.
Women undergoing trial labor need to be reassured, as well as her support person, that cesarean birth is only an alternative, not an inferior, method of birth because the labor is not progressing.

External Cephalic Version

External cephalic version is the turning of a fetus from a breech to a cephalic position before birth.
As early as 34 to 35 weeks external cephalic version can be done but the usual time is 37 to 38 weeks of pregnancy.
Record FHR and ultrasound continuously during the procedure.
The uterus should relax, so administration of a tocolytic agent is done.
The breech and vertex of the fetus are located and grasped transabdominally by the examiner’s hands on the woman’s abdomen.
External cephalic version can decrease the number of cesarean births necessary from breech presentations.
Contraindications to the procedure include multiple gestation, severe oligohydramnios, vaginal birth, cord coil, and unexplained third trimester bleeding which could be placenta previa.
The feeling of pressure may be uncomfortable for the woman.
Women who are Rh negative should receive Rh immunoglobulin after the procedure in case bleeding occurs.

1. A woman with a fetus in occipitoposterior position would commonly demonstrate which of the following?

A. Acute chest pain
B. Increased energy levels
C. Intense back pressure
D. Precipitate labor

2. What is the most common complication for the mother of an oversized fetus?

A. Uterine dysfunction
B. Precipitate labor
C. Prolonged labor
D. Diabetes mellitus

3. Which of the following suggests that the woman has shoulder dystocia?

A. Primiparity
B. Premature pregnancy.
C. Prolonged second stage of labor
D. Immediate descent

4. To aid in fetal rotation in an occipitoposterior position, the nurse should instruct the woman to:

A. Assume Trendelenburg’s position
B. Assume a fetal position.
C. Assume a side lying position on the side where the fetal back lies.
D. Assume a hands and knees position

5. This condition predisposes the woman to an oversized fetus:

A. Occipitoposterior position.
B. Gestational diabetes
C. Primiparity
D. CPD

6. A woman in the second trimester of her pregnancy with a fetus in breech position worries that she would deliver the fetus through cesarean delivery. What should the nurse tell her?

A. Cesarean delivery is one of the safest and most economical methods of giving birth.
B. The fetus would have to be delivered via cesarean section because it will remain in a breech position until birth.
C. The fetus may still turn into a cephalic position by week 38 because the lower extremities fit more properly in the fundus.
D. She can still deliver vaginally even though the fetus is in breech position.

7. A pregnant woman with a fetus in face presentation asks if there is any chance that she would deliver her baby vaginally. The nurse should tell her that:

A. Vaginal birth is impossible because the head diameter that the fetus presents to the pelvis is too large.
B. The baby can be born vaginally if the chin is anterior and the pelvic diameters are within normal limits.
C. The baby can be born vaginally because face presentation is the same with cephalic presentation.
D. Vaginal birth is contraindicated to a fetus with face presentation and there is no chance for the mother to give birth vaginally.

8. In brow presentation, the head becomes jammed in the brim of the pelvis as the occipitomental diameter presents, and this usually results in:

A. Prolonged labor
B. Precipitate labor
C. Normal labor
D. Obstructed labor

9. A baby born in a brow presentation has extreme ecchymosis on the face. The nurse should tell the parents that:

A. The bruising can be relieved by a cold compress.
B. The bruising is normal and would disappear after several days.
C. They should refer the condition to a pediatrician for immediate treatment.
D. The bruising is a permanent condition and nothing could relieve it.

10. In face presentation, when is cesarean birth necessary?

A. If the chin is anterior.
B. If the chin is posterior.
C. If the pelvic diameters are within normal limits.
D. If the pelvic diameters are higher than normal.

11. What is inlet contraction?

A. The narrowing of the transverse diameter at the outlet to less than 11 cm.
B. Determination of the progress of labor in a woman who has borderline inlet measurement with a good fetal lie and position.
C. The narrowing of the anteroposterior diameter to less than 11 cm.
D. The narrowing of the anteroposterior diameter to less than 21 cm.

12. What is the usual cause of inlet contraction?