Firecracker - Labour

Question 1

How common is vertex presentation?

Answer 1

Normal fetal presentation,also known as cephalic or vertex is where the fetal head is downard, with a tucked chin and the occiput aimed towards the birth canal.

Vertex presentation is the fetal position in over 95% of pregnancies.

Question 2

How does preterm labour present?

Answer 2

• Patients experiencing preterm labour present with:
  
  • constant low back pain
  • cramping
  • signs of albour <37 weeks’ gestation

Question 3

What is often given with Pitocin (synthetic oxytocin) to induce labour and ripen the cervix?

Answer 3

Pitocin does not induce cervical ripening, so misoprostol is sometimes given in combination for this purpose.

Question 4

What is face presentation of the fetus?

Answer 4

Face presentation occurs rarely and is a full hyperextension of the fetal neck. It usually undergoes normal delivery as long as the fetal chin is anterior.

Question 5

What is preterm rupture of membranes?

Answer 5

Premature rupture of membranes (PROM) refers to spontaneous rupture of the amniotic sac with spillage of amniotic fluid before the onset of labour.

Rupture of membranes before 37 weeks is termed preterm rupture of membranes, which is a common cause of preterm labour.

If the rupture occurs for longer than 18 hours of delivery, it is described as prolonged rupture of membranes:

Risk factors associated with PROM:

Vaginal or cervical infection

Cervical incompetence

Poor maternal nutrition

Prior to PROM

Question 6

What is brow presentation of the fetus?

Answer 6

Brow presentation occurs very rarely and is a partial hyperextension of the neck, causing the largest surface area of the head aimed towrds the birth canal. This presentation requiers cesarean delivery if the head does not spontaneously correct to a normal presentation during labour.

Question 7

What is preterm labour?

Answer 7

• Preterm labour refers to the onset of labour before 37 weeks’ gestation, risk factors include:
  
  • prior preterm labour, preterm premature rupture of membranes (PPROM) and chorioamnionitis
  • Multiple gestations
  • Uterine anomalies and placental abruption
  • Pre-eclampsia
  • Low socio-economic status
  • Smoking and substance abuse

Question 8

How does premature rupture of membranes present?

Answer 8

• PROM presents with loss of amniotic fluid from the vagina and the amniotic fluid may be seen pooling in the vagina on visual examination
• Internal manual examination should not be performed in cases of PROM because of an increased risk of introducing infection into the vaginal canal.
• Vaginal fluid should be cultured to detect infection.

Question 9

What is the role of speculum exam in the diagnosis of premature rupture of membranes?

Answer 9

• Sterile speculum exam (performed without gel) can detect pooling or fluid in the vagina
• Nitrazine paper can be used to detect amniotic fluid in the vaginal fluid, which willl turn blue upon exposure
• Microscopic examination of vaginal fluid will show ferning (due to the fern like pattern of cervical mucus) if amniotic fluid is present in the vaginal fluid
• Ultrasound can be used to confirm oligohydramnios to assess the volume of residual amniotic fluid and to determine the fetal position.

Question 10

How does chorioamnionitis present?

Answer 10

• Chorioamnionitis is an infection of the membrane and amniotic fluid surrounding the fetus. It is the most common precursor of neonatal sepsis.
• The presentation of chorioamnionitis includes:
  
  • ROM
  • Maternal fever
  • Elevated maternal white count
  • Uterine tenderness in the absence of other known source of fever such as URI or UTI
  • Fetal tachycardia
• Suspected chorioamnionitis should be treated with ampicillin, gentamicin and clindamycin.
• Delivery should be hastened.

Question 11

What are some complications of breech position?

Answer 11

Complications of breech position include:

Cord prolapse
Head entrapment
Fetal hypoxia
Abruptio placentae
Birth trauma

Question 12

What is breech position and how is it diagnosed?

Answer 12

• Breech position is the most common malrepresentationw hich is where the buttocks instead of the head is directed towards the vaginal canal.
• breech position is noted in 25% of pregnancies before 28 weeks of gestation, but most of these become vertex by the time of birth
• Frank breech makes up 75% of cases and presents with flexed thighs and extended knees so that the feet are near the head
• In complete breech the fetal thighs and knees are both flexed
• In a footing breech one or both of the fetal legs are extended so that the leg lies below the breech in the birth canal
• Risk factors incldue:
  
  • Prematurity
  • Multiple gestation
  • Polyhydramnios
  • Uterine anomaly
  • Placenta previa
• Abdominal examination of breech presentation can detect the fetal head in the abdomen. Vaginal examination can detect the presenting part.
• Performing an ultrasound will confirm breech position.

Question 13

How is breech position managed?

Answer 13

• If breech position does not resolve by 37 weeks it can be managed in one of three ways:
  
  • ECV (external cephalic version
    
    • Used at 37 weeks of gestation in an attempt to reposition the fetus, and is effective in up to 75% of cases.
    • However, this procedure is so painful for the patient that it normally requires epidural anesthesia and it carries a small risk of fetal intolerance, excessive cord traction or placental abruption necessitating an emergency ‘‘crash’’ early term C-section
  • Scheduled C-section
    
    • ultimately performed in most cases.
    • this approach minimises risk of an emergency C-section but many patients elect to undergo an ECV in an attempt to have a vaginal delivery
  • If a patient goes into spontaneous labour with an infant in breech position, a C-section should be performed.

Question 14

What is the role of dinoprostone in the induction of labour?

Answer 14

dinoprostone (cervidil) is a prostaglandin E-2 analogue that softens the cervix and induces uterine contractions. It can be significantly more expensive than misoprostol.

Question 15

What is the most reliable indicator of whether or not an induced labour will be successful?

Answer 15

• The likelihood of successfully inducing labour is based on cervical status.
• The bishop socre is the most reliable indicator of whether or not an induced labour will be successful
• A greater likelihood of successful vaginal delivery, and thus higher Bishop score is associated with:
  
  • Greater cervical dilatation and effacement
  • Softer cervix
  • More anterior cervical position
  • Greater (lower) station
• A lower likelihood of vaginal delivery and thus lower Bishop score is associated with a higher likelihood of requiring a Cesarean delivery after the attempted induction of labour is 30% if the Bishop socre was calcuated. as less than 3 and 15% if greater than 3)

Question 16

What is the role of ultrasound in the management of preterm labour?

Answer 16

Ultrasound should be used to assess amniotic fluid volume, fetal well-being, and to verify gestational age.

Urine, vaginal, and cervical cultures should be performed to detect infection.

Ultrasound can also be used to measure cervical length. A cervical length >35 mm is associated with a very low risk of preterm birth and a length <15 mm has a high risk of preterm birth.

Question 17

What reasons are not indications for inducing labour?

Answer 17

Induction of labor is not indicated for the following reasons:

Maternal anxiety or normal discomfort from pregnancy
A previous pregnancy with labor abnormalities. Note: Patients with a history of shoulder dystocia are often given the option of an elective cesarean section.

Question 18

What are some maternal indications for inducing labour?

Answer 18

Agents commonly used to induce labor include oxytocin (Pitocin) and misoprostol (Cytotec).

Inducing labor is indicated when the maternal/fetal risks of continuing the pregnancy are greater than with early/induced delivery.

Maternal indications for inducing labor include:

Preeclampsia, eclampsia, or HELLP syndrome
Diabetes mellitus
Stalled stage of labor
Chorioamnionitis
Abruptio placentae

Question 19

What are some fetal indications for inducing labour?

Answer 19

Fetal indications for inducing labor include:

Prolonged, or postterm pregnancy (>40-42 weeks gestation)
Intrauterine growth restriction
Premature rupture of membranes (PROM)
Multiple gestation
Some congenital defects
Fetal demise

Question 20

What is the minimum gestational age at which elective induction could be considered?

Answer 20

Elective induction should not be performed before 39 weeks’ gestation because of the increased risk of neonatal morbidity.

Question 21

How should PROM be managed?

Answer 21

In treating PROM, the risk of chorioamnionitis must be balanced with the risk of prematurity.

If PROM occurs at <32 weeks’ gestation, corticosteroids should be used to hasten fetal lung maturity. Antibiotics should be given prophylactically for group B strep. Labor should be induced once amniotic fluid analysis indicates fetal lung maturity.

If PROM occurs between 32 to 34 weeks’ gestation, amniotic fluid analysis is performed to determine fetal lung maturity. Labor should be induced if lung maturity has occurred, but if not corticosteroids and antibiotics should be administered until they mature.

If PROM occurs >34 weeks’ gestation, antibiotics should be administered and delivery should be induced.

Question 22

What is the role of ultrasound in the management of premature rupture of membranes?

Answer 22

Ultrasound can be used to confirm oligohydramnios, to assess the volume of residual amniotic fluid, and to determine the fetal position.

Question 23

What ultrasound findings correlate with risk of preterm birth?

Answer 23

Ultrasound should be used to assess amniotic fluid volume, fetal well-being, and to verify gestational age.

Urine, vaginal, and cervical cultures should be performed to detect infection.

Ultrasound can also be used to measure cervical length. A cervical length >35 mm is associated with a very low risk of preterm birth and a length <15 mm has a high risk of preterm birth.

Question 24

What are the contraindications to using synthetic oxytocin to induce labor?

Answer 24

Contraindications to the use of synthetic oxytocin include:

Fetal distress
Premature delivery
Unfavorable fetal position.
It is not indicated for elective induction of labor.

Question 25

What is Pitocin?

Answer 25

Synthetic oxytocin (Pitocin) is identical to the oxytocin produced by the hypothalamus. It is used to induce labor and control postpartum bleeding by inducing contraction of the uterine myometrium.

It also has anti-diuretic properties similar to ADH, so it can lead to hyponatremia, seizures and death if used inappropriately. There is also a risk of subarachnoid hemorrhage and uterine rupture.

Question 26

In general, what would contraindicate induction of labor?

Answer 26

Contraindications to induction of labor are situations in which inducing labor would pose greater maternal/fetal risk than performing a cesarean section.

Settings in which induction of labor is contraindicated include:

Prior uterine rupture or surgery
Active genital herpes infection
Fetal lung immaturity
Malpresentation
Umbilical cord prolapse
Placenta previa

Question 27

What is induction of labor? What is augmentation of labor?

Answer 27

Inducing labor refers to intervening to initiate uterine contractions prior to the onset of labor.Labor augmentation is used to speed the progress of labor.

Question 28

What is the role of misoprostol in the induction of labor?

Answer 28

Misoprostol (Cytotec) is a PGE1 analogue that causes uterine contractions and effacement of the cervix (also known as cervical ripening).

Question 29

What is a Foley bulb induction?

Answer 29

Foley bulb induction involves the placement of the balloon portion of a Foley between the amniotic sac and lower uterus which is then inflated with saline solution in order to mechanically open the cervix.

When the cervix dilates to 3 cm, the catheter will slide out on its own and the labor may start without any pharmacologic intervention.

This method can also be used to make the cervix more favorable for a Pitocin induced labor.

Question 30

Why should internal manual examination not be performed in cases of premature rupture of membranes?

Answer 30

Internal manual examination should not be performed in cases of PROM because of an increased risk of introducing infection into the vaginal canal. Vaginal fluid should be cultured to detect infection.

Question 31

What risks are associated with the use of synthetic pitocin to induce labor?

Answer 31

It also has anti-diuretic properties similar to ADH, so it can lead to hyponatremia, seizures and death if used inappropriately. There is also a risk of subarachnoid hemorrhage and uterine rupture.

Question 32

What complications are associated with preterm birth?

Answer 32

Premature infants are at increased risk for respiratory distress syndrome (worsens with shorter gestational age), intraventricular hemorrhage, sepsis, and necrotizing enterocolitis.

Question 33

What gestational age dictates how preterm labor is treated?

Answer 33

Treatment varies based on whether the gestational age is less than 34 weeks’ gestation or greater than 34 weeks’ gestation.

At <34 weeks’ gestation, preterm labor should be managed with the following:

Expectant management (even if preterm premature rupture of membranes)
Hospitalization, hydration, and activity restriction
Tocolytic therapy with magnesium sulfate (still tested, though not commonly used), terbutaline, indomethacin, or nifedipine for 48 hours
Glucocorticoids (betamethasone or dexamethasone) for 48 hours to assist with fetal lung maturation
Empiric ampicillin for prophylaxis against group B strep if delivery is imminent or if there is evidence of active infection

At >34 weeks’ gestation, preterm labor should be managed with the following:

Expectant management if fetal lung maturity has been proven
Active management if there is an indication for delivery, such as nonreassuring fetal testing, infection, or maternal threat
Tocolysis and glucocorticoids have no proven benefit after 34 weeks’ gestation.
Empiric ampicillin if delivery is imminent