Normal Labor and Delivery

• Labor and delivery


  When a patient first presents to the labor floor, a quick initial assessment is made using the history of present pregnancy, obstetric history, and the standard medical and social history
• Obstetric examination


  1. Maternal abdominal examination for contractions and the fetus (Leopold maneuvers)

  2. Cervical examination

  3. Fetal heart tones

  4. Sterile speculum examination if rupture of membranes is suspected

  5. Obstetric ultrasound evaluation of the cervical length and fetal presentation
• Fetal lie


  Whether the infant is longitudinal or transverse within the uterus
• Leopold maneuvers


  Palpating at the fundus of the uterus, then on either side of the uterus, and finally, palpation of the presenting part just above the pubic symphysis
• Fetal presentation


  Breech or vertex (cephalic)
• Diagnosis of rupture of membranes (ROM) is suspected with a history of a gush or leaking of fluid from the vagina, although sometimes it is difficult to differentiate between stress incontinence and small leaks of amniotic fluid
• Diagnosis of ROM


  1. Pool test

  2. Nitrazine test

  3. Fern test

  4. Ultrasound examination

  5. Amniocentesis with indigo carmine dye

  6. Amnisure rapid test
• Bishop score


  • Dilation
  • Effacement
  • Fetal station
  • Cervical position
  • Consistency of the cervix
• Dilation


  Assessed by using one or two fingers to determine how open the cervix is at the level of the internal os, measured in centimeters from 0 to 10
• Effacement


  Determines how much length is left of the cervix and how effaced (thinned out) it is, can be reported by percent or by cervical length
• Station


  The relation of the fetal head to the ischial spines of the female pelvis, measured from -3 to +3
• Cervical consistency


  Whether the cervix feels firm, soft, or somewhere in between
• Cervical position


  Ranges from posterior to mid to anterior
• Fetal presentation


  Vertex (head down), breech (buttocks down), or transverse (neither down)
• Fetal position


  Based on the relationship of the fetal occiput to the maternal pelvis, can be occiput transverse (OT) or occiput posterior (OP)
• Labor


  Contractions that cause cervical change in either effacement or dilation
• Prodromal labor


  Irregular contractions that vary in duration, intensity, and intervals and yield little or no cervical change
• Induction of labor


  The attempt to begin labor in a nonlaboring patient
• Augmentation of labor


  Intervening to increase the already present contractions
• Indications for induction of labor

  • Postterm pregnancy
  • Preeclampsia
  • Diabetes mellitus
  • Nonreassuring fetal testing
  • Intrauterine growth restriction
• Elective induction of labor at 37 and 38 weeks of gestation has been shown to lead to higher rates of neonatal morbidity and should be avoided
• Elective induction of labor at 39 and 40 weeks of gestation is unclear whether it is associated with an increase in cesareans
• In studies of elective induction of labor at 41 weeks of gestation, there appears to be a decrease in the overall rate of cesarean
• Elective induction of labor at 41 weeks of gestation appears to decrease the overall rate of cesarean
• In three very small, non-US studies of elective induction of labor prior to 41 weeks of gestation, there appears to be a decrease in the overall rate of cesarean as well
• Future studies, particularly ones that will reflect practice in a variety of settings, will be necessary to demonstrate such a potential benefit
• Preparing for Induction


  1. Discuss the situation with the patient

  2. Form a plan for induction
• When the indication for induction is more pressing, induction should be started without significant delay
• Bishop score


  A measure of cervical status that determines the success of an induction
• A Bishop score of 5 or less may lead to a failed induction as often as 50% of the time
• Cervical ripening


  Use of prostaglandins (PGE2 gel, PGE2 pessary, PGE1M) or mechanical means (Foley bulb)
• Contraindications for use of prostaglandins

  • Maternal: asthma, glaucoma
  • Obstetric: prior cesarean, nonreassuring fetal testing
• PGE2 gel cannot be turned off with the ease of oxytocin, so there is a risk of uterine hyperstimulation and tetanic contractions
• Induction


  1. Cervical ripening and dilation

  2. Oxytocin (Pitocin) administration

  3. Amniotomy
• Augmentation


  Use of Pitocin and amniotomy for inadequate contractions or prolonged labor
• Aggressive augmentation, active management of labor, involves both oxytocin and amniotomy and has been demonstrated to lead to shorter labor courses but no difference in cesarean delivery rates
• Fetal heart rate


  Normal range is 110-160 beats per minute
• Fetal heart rate above 160 may indicate fetal distress due to infection, hypoxia, or anemia
• Prolonged fetal heart rate deceleration of greater than 2 minutes' duration with a heart rate less than 90 beats per minute is of concern and requires immediate action
• External electronic fetal monitoring

  • Provides more subtle information including heart rate variations
  • Easier to gather and record data, allowing more time for analysis