Compared to vaginal delivery, cesarean delivery has greater risk of maternal severe morbidity and mortality. The international healthcare community has defined an ideal prevalence of cesarean delivery to be between 10% to 15%. Currently in the United States, one in three women give birth by cesarean delivery.
Several approaches have been used to decrease the prevalence of cesarean delivery. One of the main strategies includes the prevention of primary cesarean delivery, which decreases long-term risks and lowers the repeat cesarean delivery rate. ACOG summarizes recommendations to safely avoid the first cesarean section.
Most common indications for cesarean delivery (starting with most frequent) include
Labor dystocia
Abnormal or indeterminate fetal heart rate tracing
Fetal malpresentation
Multiple gestation
Suspected fetal macrosomia
Dystocia in the First Stage of Labor
Consortium on Safe Labor: Contemporary labor data in the United States
In a multi-center retrospective study, Zhang et al. reviewed the data of more than 60,000 normal deliveries from 2002 to 2008, constructing average labor curves showing that
Cervical dilation was slower until 6cm | Previously 4cm as described by Friedman
Time to progress from 4 to 10 cm was significantly higher than previously described
Latent phase
Latent phase, defined as prior to 6 cm, is no longer a criterion for cesarean section
Augmentation is recommended
Most patients will experience active labor spontaneously or after intervention (amniotomy and or oxytocin)
Allowing for longer duration of latent phase may avoid cesarean sections for failed induction, defined as rupture of membranes and oxytocin for 12 to 18 hours without cervical change
ACOG states that
Because they are contemporary and robust, it seems that the Consortium on Safe Labor data, rather than the standards proposed by Friedman, should inform evidence-based labor management
Active phase
Dilation of at least 6 cm should be considered the threshold for active phase
Cesarean delivery for arrest of dilation should be reserved for patients with the following criteria
≥6 cm dilated with ruptured membranes and
≥4 hours of adequate uterine contractions and no cervical change or
≥6 hours of oxytocin without adequate uterine activity and no cervical change
Note: There is an association between duration of first stage of labor and chorioamnionitis, but causality is unclear
Dystocia in the Second Stage of Labor
Longer duration of second stage of labor may be associated with adverse neonatal outcomes but risk appears to be low and incremental
Arrest of labor in the second stage diagnosis: No descent while pushing for 2 hours in multiparous and 3 hours in nulliparous patients without epidural anesthesia
Individualizing care and allowing for longer durations in certain patients who have received an epidural may be appropriate
Operative vaginal delivery
Safe alternative to cesarean when performed by skilled physicians
Encourage training, and ongoing maintenance, of practical skills
Manual rotation of the fetal occiput
Reduces cesarean rates whether successful or attempted
Frequently assess fetal position in second stage of labor, especially if there is abnormal fetal descent
Abnormal or Indeterminate Fetal Heart Rate Tracings
Category III
Category III tracings are associated with fetal acidemia, cerebral palsy and encephalopathy and require expedient intervention
If intrauterine resuscitation (eg. repositioning, stopping oxytocin, assessment of hypotension) fails to improve the tracing, deliver rapidly and safely
Category II
Category II is common and comprises a diverse spectrum of patterns
Minimal variability, prolonged decelerations or recurrent late decelerations require intervention
Initiate intrauterine resuscitation with evaluation for other causes such as umbilical cord prolapse
Recurrent variable decelerations are not themselves pathologic but may lead to fetal acidemia
Scalp stimulation may help assess fetal acid-base status in presence of abnormal or indeterminate tracing
Note: Use of an algorithm, such as the Shields algorithm or Clark algorithm, may help guide management of Category II tracings (see ‘Primary Sources – Learn More’ below)
Fetal Malpresentation
Assess presentation beginning at 36w0d
External cephalic version (ECV) should be offered whenever possible at term | Success may be enhanced by terbutaline and regional anesthesia
One study showed an increased rate of successful ECV in patients that received regional anesthesia than ones that did not (79% success with anesthesia vs 56% success without)
The combination of anesthesia and tocolysis is associated with increased rates of success ECV, cephalic presentation in labor, and vaginal delivery
Twin Gestation
Perinatal outcomes are not improved by cesarean if the first twin is in cephalic
Cephalic/cephalic or cephalic/non-cephalic should be counseled to attempt vaginal delivery
Residents should be trained to perform twin deliveries and second breech extraction
Suspected Fetal Macrosomia
Limit cesarean delivery to
Without diabetes: Estimated fetal weight ≥5000 grams
With diabetes: Estimated fetal weight ≥4500 grams
Third trimester ultrasonography fetal weight estimate should be used sparingly and with clear indications
Patients should be counseled that the ultrasound estimation of fetal weight in late gestation is inaccurate
Weights ≥5000 grams are rare
Clinical Scenarios that May Prevent Avoidable Cesarean Delivery
Elective Induction of Labor at 39 weeks
The ARRIVE trial was an RCT comparing elective induction at 39 weeks with expectant management in low-risk nulliparous patients
Primary fetal outcome: No statistical difference in perinatal mortality and severe morbidity
Pre-specified major maternal outcome
Cesarean delivery rate was significantly lower in the induction of labor group (18.6% versus 22.2%)
Note: Allow 24 h or more in the latent phase before diagnosing failed induction | Rupture of membranes and oxytocin for 12 to 18 hours must be present prior to diagnosis of failed induction
Excessive Maternal Weight Gain
Optimal weight gain during pregnancy varies by pre-pregnancy BMI
BMI <18.5: Weight gain between 18 to 40 lbs
BMI 18.5 to 24.9: Weight gain between 25 to 35 lbs
BMI 25.0 to 29.9: Weight gain between 15 to 25 lbs
BMI >30: Weight gain between 11 to 20 lbs
Weight gain above the recommended limits is associated with increased rates of cesarean delivery and adverse outcomes
Counseling about appropriate weight gain, diet and exercise is appropriate throughout pregnancy to prevent excessive weight gain
Herpes Simplex Virus
Recommendation is for prevention of outbreaks at time of delivery in women with history of genital herpes
Oral antiviral should be initiated within 3 to 4 weeks of delivery, at the latest starting at 36 weeks
Organizational level interventions
Changing local culture and attitudes using multifaceted interventions
Provider audits
Feedback or huddles
Second opinions
Continuous labor and delivery support | One-on-one support (such as doula) improves patient satisfaction and reduces the rate of cesarean delivery
Medico-legal pressures, tort reform
Provide better knowledge base for clinical decisions
KEY POINTS:
Prolonged duration of latent phase of labor is not an indication for cesarean delivery
Cervical dilation of 6 cm should be the threshold for active phase of labor
Arrest of active phase of labor is defined as failure to progress after ruptured membranes and 4 hours of adequate or 6 hours of inadequate uterine activity
Arrest of second stage should be at least 2 hours in multiparous and 3 hours in nulliparous | Longer durations may be appropriate with regional anesthesia
Not all fetal heart rate tracing abnormalities are an indication for cesarean
Encourage operative delivery procedures when appropriate can help prevent cesarean delivery
Access to nonmedical interventions and changes in organizational level may reduce cesarean delivery rates
The purpose of induction of labor is to stimulate uterine contractions before onset of spontaneous labor for vaginal delivery. The rates of induction of labor have significantly increased during the last decades. In 1990, less than 10% of pregnancies underwent induction of labor, vs 30% by 2019. Currently, induction of labor is one of the most frequently performed obstetric procedures. A recent RCT comparing elective induction of labor at 39 weeks gestation with expectant management in nulliparous people (the ARRIVE trial – see below in ‘Related ObG Topics’), showed no increase in perinatal morbidity and mortality rates with lower rates of cesarean delivery. These results may lead to an increase in induction rates in the near future.
Indications
Indications include but are not limited to the following
Risk of rapid labor | Distance to hospital | Psychosocial indications
Note: See summary of guidance on timing of delivery for medical indications below in ‘Related ObG Topics’
Contraindications
Similar to contraindications for vaginal delivery
Vasa previa or complete placenta previa
Transverse fetal lie
Umbilical cord prolapse
Previous classical cesarean delivery
Active genital herpes infection
Previous myomectomy entering endometrial cavity
Cervical Preparation
Bishop Score
A Bishop score of ≤6 is associated with low rate of successful induction with oxytocin alone, and the use of cervical ripening agents are recommended
Cervical Ripening Agents
Misoprostol (PGE1 analogue) given intravaginally, orally or sublingually
Initial dose: 25 mcg every 3 to 6 hours
Delay oxytocin 4 hours after last dose
Available evidence supports safety and efficacy
Higher rates of tachysystole
When compared to PGE2
With dosing ≥50 mcg
Contraindications: Prior cesarean and/or uterine surgery due to risk for uterine rupture
Dinoprostone (PGE2 preparations) given vaginally via gel or insert
0.5 mg in 2.5 ml syringe gel or 10 mg vaginal insert
Second dose after 6 to 12 h (maximum dose of 1.5 mg in 24 hours)
Delay oxytocin 6 to 12 hours after last application of gel or 30 to 60 min after insert
Note: After prostaglandin use (misoprostol or dinoprostone), patient should remain recumbent for at least 30 minutes | Fetal heart tracing should be monitored continuously for 30 minutes to 2 hours | FHR monitoring should be continued if regular uterine contractions are persistent
Mechanical dilators
Foley catheter ( 30 to 80 ml): Reasonable and effective option for cervical ripening
Pitocin is synthetic formulation for oxytocin, with both low-dose and high-dose regimens
Low-dose regimen: 0.5 to 2 mU with increasing rate of 1 to 2 mU/min every 15 to 40 minutes
High-dose regimen: 6 mU with increasing rate of 3 to 6 mU/min every 15 to 40 minutes
High-dose regimen:
Shorter labor | Less chorioamnionitis | Less cesarean
More tachysystole with FHR changes
Myometrium becomes more sensitive to oxytocin increases with advancing gestation
Management of tachysystole with FHR changes
Decrease/discontinue oxytocin
Corrective measures: Turn patient on side | Oxygen | Fluids | Terbutaline
Membrane Stripping
Mechanical technique
Insertion of one or two fingers into the cervix | Continuous circular sweeping motion detaches the inferior pole of the membranes from the lower uterine segment
Reduces rates of formal induction (2.3% vs 3.1%) and increases rates of spontaneous labor (72% vs 60%)
Positive GBS – insufficient data for recommendation
Amniotomy
Better when cervix is favorable
In combination with oxytocin: Reduces interval from induction to delivery by approximately 5 hours
Risks: Cord prolapse | Chorioamnionitis
Avoid, if possible: HIV, hepatitis B or hepatitis C
Positive GBS: No data to suggest increased risk for neonatal disease when appropriate intrapartum antibiotic prophylaxis is given
Nipple Stimulation
Increase likelihood of labor when cervix is favorable
Only studied in low-risk populations
In meta-analysis
Decrease in women not in labor after 72 hours
Decrease in PPH
No impact on meconium-stained amniotic fluid or cesarean delivery
Due to association with an increased trend toward association with perinatal death “this practice is not recommended in an unmonitored setting”
Specific Clinical Scenarios
Ruptured Membranes
Induction with oxytocin is associated with decreased
Interval between PROM and delivery
Frequency of chorioamnionitis
Postpartum febrile morbidity
Prostaglandins appear safe and effective
Intrauterine Fetal Demise
<28 weeks
Misoprostol 200 to 400 mcg vaginally every 4 to 12 hours
>28 weeks
Standard obstetric protocol for labor induction
Prior uterine scar
<28 weeks: 400 mcg vaginally every 6 hours | “does not appear to be an increase in complications”
>28 weeks: Foley for cervical ripening
Trial of labor is reasonable if prior low transverse cesarean delivery
Prior classical incision
Limited data to guide clinical practice
KEY POINTS:
Prior to starting an induction of labor, contraindications should be reviewed
Cervical ripening is recommended with a Bishop score of ≤6
Predictors of induction success
Lower BMI | Greater dilation | Higher parity | Term gestational age
Pharmacologic and non-pharmacologic methods can be used for induction based on the patient’s characteristics
Misoprostol regimens are recommended for intrauterine fetal demise including TOLAC
There is no strong consensus to define failed induction
At least 12 to 18 hours of latent labor with oxytocin and AROM should be allowed before diagnosing failed induction
The ARRIVE Trial and Professional Guidance: Elective 39 Week Induction to Reduce the Risk of Cesarean Section
SUMMARY:
The ARRIVE study (A Randomized Trial of Induction Versus Expectant Management), authored by Grobman et al. (NEJM, 2018), was undertaken to determine if elective induction of labor (IOL) of low-risk nulliparous women at 39 weeks reduces adverse perinatal and neonatal morbidity compared to expectant management. Both SMFM and ACOG have addressed the ARRIVE findings.
SMFM Recommendations
It is reasonable to offer elective IOL to low-risk, nulliparous women at or beyond 39 weeks and 0 days of gestation. We recommend that providers who choose this approach ensure that women meet eligibility criteria of the ARRIVE trial.
We recommend against offering elective IOL to women under circumstances that are inconsistent with the ARRIVE study protocol unless performed as part of research or quality improvement.
We recommend that further research be conducted to measure the impact of this practice in settings other than a clinical trial.
ACOG Clinical Practice Update
Patients should receive counseling regarding the potential benefits and risks of induction of labor at or beyond 39 weeks of gestation compared with expectant management
Hospitals and health systems, in collaboration with clinicians, should evaluate the available resources to accommodate these inductions of labor, with active effort toward maintaining equitable delivery of care
To account for an interim analysis, a two-tailed P value of <0.046 was used for statistical significance threshold
Cesarean delivery was less frequent in the induced labor group (19%) vs the expectant management group (22%)
RR 0.84; 95% CI 0.76-0.93
Preeclampsia and gestational hypertension occurred in 9.1% of the induced group vs 14.1% of the expectant management group
RR 0.64; 95% CI 0.56-0.74
Among newborns, 3% in the induced group needed respiratory support vs 4.2% in the expectant management group
RR 0.71; 95% CI 0.55-0.93
Conclusions
There was no difference between groups with respect to composite adverse perinatal outcome, but there was reduced frequency of cesarean section in the induction group
There was increased incidence of maternal hypertension/preeclampsia and newborn respiratory support in the expectant management group
The authors state
Our data suggest that 1 cesarean delivery may be avoided for every 28 deliveries among low-risk nulliparous women who plan to undergo elective induction of labor at 39 weeks.
KEY POINTS:
Induction Protocol Highlights
Patients had a cervical exam between 72 hours prior to randomization and 24 hours after randomization
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