Lesson 6: Management of Difficult Labor in Pregnant Women

Lesson 6: Management of Difficult Labor in Pregnant Women

# 1. Causes of Difficult Labor

1.1. Mechanical causes

These are all the causes that hinder the descent and expulsion of the fetus.

1.1.1. Causes related to the mother

• 1.1.1.1. Abnormal pelvis:

• Narrow pelvis:

• Narrow inlet: The anteroposterior diameter is narrow (normal > 10.5cm), the transverse diameter is narrow (normal > 12.5cm), one diameter is narrow, or all diameters are narrow.

• Narrow midpelvis: Even narrowing (generalized narrowing) or uneven narrowing (asymmetric narrowing, distorted pelvis, deviation).

• Narrow outlet: The anteroposterior diameter is narrow (normal > 9.5cm, can increase to 11.5cm when the fetal head descends), the transverse diameter is narrow (normal > 11cm) due to the shortening of the ischial spines.

• Clinically:

• Total narrowing: All diameters are reduced, the sacral promontory-posterior vaginal wall distance < 8.5cm. If not detected early, it can lead to threatened uterine rupture, uterine rupture. Cesarean section is necessary when the fetus is full term and there are signs of labor.

• Limited pelvic narrowing: The sacral promontory-posterior vaginal wall distance is 8.5 – 9.5cm. During labor, the engagement of the fetal head can be assessed. Cesarean section if the fetal head is not engaged.

• Pelvic deformation:

• Narrowing the inlet:

• Flat pelvis: The anteroposterior diameter is shorter than normal. Diagnosis is based on the sacral promontory-posterior vaginal wall distance.

• Pelvis with the spine protruding forward: Makes the inlet narrow, the outlet wide. Diagnosis is based on measuring the sacral promontory-posterior vaginal wall distance.

• Narrowing the outlet:

• Pelvis with the spine curving backward: Occurs in people with hunchback, spinal tuberculosis. Funnel-shaped pelvis. The fetus enters the inlet but cannot pass the outlet. Diagnosis: the interspinous diameter < 9cm, the fetus cannot be expelled.

• Distorted pelvis (deviated, asymmetric): Occurs in people with rickets, congenital hip dislocation, paralysis on one side. Diagnosis based on measuring the Michaelis’ rhomboid.

• 1.1.1.2. Due to a presenting tumor:

• Tumor located in the pelvic cavity, such as ovarian tumor, uterine fibroid, fallopian tube tumor, vaginal tumor, pelvic tumor (kidney tumor, rectal tumor, bladder tumor).

• Presenting tumors are rare.

• 1.1.1.3. Due to vaginal stenosis:

• Congenital stenosis.

• Tears from previous deliveries that are not sutured well.

• Surgery related to the vagina.

1.1.2. Difficult labor due to fetal causes:

• Fetal macrosomia.

• Due to fetal abnormalities: Fetal macrosomia in parts (head, shoulders, abdomen), conjoined twins.

• Due to presentation, position.

• Due to placental entanglement in multiple pregnancies.

1.1.3. Difficult labor due to fetal adnexa:

• Placenta previa:

• Complete central placenta previa: Emergency cesarean section due to bleeding, no way out.

• Other placenta previa: Amniotomy to prevent bleeding, cesarean section.

• Umbilical cord: Short, wrapped around the neck, twisted, knotted.

• Polyhydramnios and oligohydramnios: The uterus is not well-adjusted.

1.2. Due to uterine contractions:

• 1.2.1. Increased uterine contractions:

• Increased intensity of uterine contractions:

• Due to the mother: Cephalopelvic disproportion, abnormal pelvis, presenting tumor.

• Due to the fetus: Fetal macrosomia, abnormal presentation, conjoined twins.

• Other causes: Uterine malformation, underdevelopment, fibroids, maternal mental instability, improper use of uterine stimulants, overdose.

• Consequences: Slow cervical dilation, uterine rupture, threatening the life of both mother and child. For the fetus: decreased uteroplacental circulation, fetal distress. Prone to uterine atony after delivery.

• Increased tone of uterine contractions:

• In labor: Cervical dilation 2cm – tone 8mmHg, full cervical dilation 10mmHg. During pushing: 12mmHg.

• High tone: Continuous uterine hardening, uterine contractions are still present but ineffective, prolonged labor.

• Causes: Prolonged labor, uterine rigidity, slow cervical dilation. Placental abruption, underdeveloped uterus, malformation, uterus in elderly women with large babies, maternal mental instability.

• Consequences: Prolonged labor, uterine rigidity, slow cervical dilation. Increased tone combined with increased uterine contractions, decreased uteroplacental circulation, fetal distress, fetal death. Uterine atony after delivery.

• 1.2.2. Decreased uterine contractions:

• Causes: Maternal systemic disease (anemia, tuberculosis), prolonged labor, premature rupture of membranes, premature rupture of membranes, polyhydramnios, multiple pregnancies, uterine fibroids.

• Consequences: Weak uterine contractions, prolonged labor, prone to uterine edema, fetal distress, uterine atony after delivery.

# 2. Signs of Difficult Labor

• Due to the mother:

• Medical history.

• Surgical history.

• Maternal body size.

• Narrow pelvis.

• Vaginal anomalies.

• Presenting tumor.

• Due to the fetus:

• Presentation and progression of the presentation:

• Uterus shaped like an egg: Usually longitudinal presentation.

• Palpating the head at the epigastrium: Breech presentation.

• Palpating the head at the hypogastrium:

• Occipital bump lower than the forehead: Vertex presentation, possible to deliver.

• Occipital bump at the level of the forehead: Possibly anterior fontanel presentation, difficult labor.

• Only the occipital bump is visible: Palpating the back, there is a cavity between the fetal back and the occipital bump (“ax stroke” sign): Brow presentation, impossible to deliver.

• The occipital bump is high and distinct, the fetal back is visible, the “ax stroke” sign is not clear: Face presentation with the chin back, difficult labor.

• The fetal back is not clearly palpable, the “ax stroke” sign is not clear: Face presentation with the chin forward, possible to deliver.

• Fetal head engagement: Assessing Delle’s engagement, fetal head engagement based on the iliac spine landmark. Normal labor, the fetal head does not descend further or does not press against the cervix (the fetal head does not progress), difficult labor.

• Fetal health: Weak fetal heart rate (assessed by obstetric monitoring machine).

• Due to the amniotic sac, amniotic membrane, amniotic fluid:

• Amniotic membrane: Thick amniotic membrane.

• Bulging amniotic sac: The adjustment of the fetal presentation and the lower uterine segment is not matched, there is still a gap.

• Premature rupture of membranes: Rupture before labor and the cervix has no signs of effacement and dilation.

• Premature rupture of membranes: After the onset of labor and the cervix has effaced and dilated but not completely.

• Amniotic fluid:

• Color: When the membranes rupture, the color is green (mixed with meconium), fetal distress or recovery from distress. Need more signs to diagnose.

• Odor: Normally has a pungent odor. Foul odor: infected amniotic fluid.

• Oligohydramnios or low amniotic fluid: Post-term fetus.

• Due to fetal adnexa:

• Umbilical cord: Prolapsed umbilical cord, wrapped around the neck, twisted, knotted.

• Due to uterine contractions:

• Increased uterine contractions:

• Increased intensity of uterine contractions: The pregnant woman is in pain, crying, and palpating the uterine fundus feels strong contractions.

• Increased intensity and baseline tone: Placental abruption.

• Decreased uterine contractions: In true labor, uterine contractions are progressing, there is cervical effacement and dilation and establishment of the amniotic sac. Then the membranes rupture, uterine contractions gradually decrease or stop, leading to prolonged labor with a risk of infection. Clinical signs: Uterine contractions are normal, the membranes rupture, uterine contractions weaken or stop, amniotic fluid flows continuously (green indicates a risk of fetal distress).

• Due to the cervix:

• Latent phase: Assessing the progress of the cervix is difficult because it progresses slowly. People often assess based on signs of premature rupture of membranes, premature rupture of membranes.

• Active phase: Over 1 hour of slow dilation, over 2 hours of difficult labor due to the cervix.

# 3. Management of Pregnant Women with Difficult Labor

3.1. Basic management:

• Encourage and support the pregnant woman emotionally.

• Diet: The pregnant woman may have a cesarean section, so advise her to try to endure, do not eat too much or drink too much water.

• Hygiene of the genitals after each examination or urination and defecation.

3.2. Monitoring the condition of pregnant women with difficult labor:

• Maternal health and medical history: Appearance, mood, vital signs.

• Pregnant women with preeclampsia: Monitor blood pressure, urine output, proteinuria, edema, subjective signs (headache, blurred vision, epigastric pain).

• Pregnant women with eclampsia: Monitor seizures, have to keep the tongue out to avoid biting the tongue.

• Monitor fetal presentation and assess fetal head engagement.

• Monitor uterine contractions.

• Monitor cervical dilation.

• Monitor fetal heart rate.

• Monitor the amniotic sac and amniotic membrane:

• Bulging amniotic sac.

• Flat amniotic sac, thick amniotic membrane.

• Premature rupture of membranes.

• Amniotic fluid color.

• Amniotic fluid odor.

# 4. Multiple choice questions

• Question 1: Which of the following causes of difficult labor is NOT related to the mother?

• A. Abnormal pelvis.

• B. Presenting tumor.

• C. Presentation, position.

• D. Vaginal stenosis.

• E. Vaginal septum.

Answer: C. Presentation, position.

• Question 2: In a pregnant woman, if the head is palpated at the hypogastrium and the occipital bump is at the level of the forehead, then:

• A. Anterior fontanel presentation, difficult labor.

• B. Vertex presentation, possible to deliver.

• C. Brow presentation, impossible to deliver.

• D. Face presentation with the chin forward, difficult labor.

• E. Face presentation with the chin back, impossible to deliver.

Answer: A. Anterior fontanel presentation, difficult labor.

• Question 3: Delle’s engagement is used to assess fetal head engagement based on which landmark of the maternal pelvis?

• A. Ischial spines.

• B. Ischial tuberosities.

• C. Pelvic brim.

• D. Iliac spines.

• E. Promontory.

Answer: D. Iliac spines.