1. Abnormal Labor and Delivery UNC School of Medicine Obstetrics and Gynecology Clerkship Case Based Seminar Series

2. Objectives Review abnormal labor patterns Describe the causes and methods of evaluating abnormal labor patterns Discuss fetal and maternal complications of abnormal labor Review indications and contraindications for oxytocin administration Review risks and benefits of trial of labor after Cesarean delivery Review strategies for emergency management of Breech, shoulder dystocia and cord prolapse

3. THE 5 “P’s” The factors that contribute to normal labor » Passageway: maternal pelvis » Power: uterine contractions » Passenger: fetus » Placenta: perfusion » Psyche: mother’s readiness

6. Abnormal Labor Patterns Remember the 3 stages of normal labor » First stage – time from onset of regular contractions to complete cervical dilation Latent – gradual cervical change Active – rapid cervical change » Second stage – time from complete cervical dilation to expulsion of the fetus » Third stage – time from expulsion of fetus to delivery of placenta Abnormal labor patterns can be divided into two general types » Protraction » Arrest

7. Friedman Labor Curve Slope of the curve changes with parity » A multipara will exhibit more rapid cervical dilation The diagnosis of protraction and arrest disorders is based on deviations from this norm

8. First and Second Stage Disorders First stage » Protraction – slower than acceptable cervical dilation <1.2 cm/hr for nulliparous women <1.5 cm/hr for multiparous women » Arrest – no cervical change No cervical change for >/= 4 hours despite adequate contractions No cervical change for >/= 6 hours with inadequate contractions Second stage » Protraction Nulliparas » Longer than 2 hours (3 with regional anesthesia) Multiparas » Longer than 1 hour (2 when regional anesthesia) » Arrest Nulliparas » No progress after >/= 4 hours with epidural (3 without) Multiparas » No progress after >/= 3 hours with epidural (2 without)

9. Disorders of the Active Phase Secondary Arrest: cessation of previously normal rate of dilation for two hours Combined Disorder: cessation of dilation when patient has previously exhibited a primary dysfunctional labor

11. Risk factors for abnormal labor Older maternal age Non-reassuring FHR Epidural anesthesia Macrosomia Maternal obesity Post-term pregnancy Cephalopelvic disproportion Occiput posterior position High station at full dilatation Nulliparity Inadequate contractions

12. Management of Abnormal Labor First stage, active phase disorders » Augmentation of labor Second stage disorders » Operative vaginal delivery

13. Bishop Score – will labor induction be successful? 0123 DilationClosed1 - 23 – 4> 5 Effacement0 – 3040 – 5060 – 70> 80 Station-3-2+1, +2 ConsistencyFirmMediumSoft PositionPosteriorMidAnterior

14. Augmentation/Induction of Labor Before augmentation assess: maternal pelvis and cervix, fetal position/station/well-being Augmentation can be achieved using: » Amniotomy Allows the fetal head to be the dilating force » Oxytocin administration » Foley bulb

15. Oxytocin Synthetic analog of peptide secreted from posterior pituitary Diluted in crystalloid and delivered IV via infusion pump » 10 units/ml; dilute in 1000 cc LR » IV bolus  hypotension » At high doses, cross reacts with ADH receptors  hyponatremia and excessive water retention Dosing – various accepted protocols, dosed to effect » Routine dose: Start at 2mu/min,  2 mu/min every 15-30 minutes to 36 IU/min » Active management of labor: start at 6 mu/min,  by 6 mu/min every 15 minutes to 36 mu/min

16. Oxytocin Indications » Labor induction in patient with high Bishop score Contraindications » Prior classical or high-risk cesarean incision » Prior uterine rupture » Active genital herpes » Placenta previa » Umbilical cord prolapse » Transverse fetal lie » Category III fetal heart rate tracing

17. Misoprostol (Cytotec®) PGE1 (prostaglandin_ Has several clinical uses » Prevention of NSAID-induced gastric ulcers » Medical termination of pregnancy » Treatment of postpartum hemorrhage Unlabeled use for labor induction or cervical ripening 25 mcg (1/4 of 100mcg tablet) in vagina Q 4 hours X 4 doses Wait 6 hours after last dose to start oxytocin Contraindicated with uterine eschar

18. Foley Bulb Place special foley through cervix and inflate balloon to 30cc Tape to thigh – remove by 12 hours Mechanism: mechanical/local release of prostaglandins Frequently used with Oxytocin

19. Forceps Assisted Vaginal Delivery Outlet forceps: » Scalp visible at the introitus w/o parting the labia » Sagittal suture < 45 degrees Low forceps: » Leading point of skull at +2 or below < 45 degrees > 45 degrees Mid-forceps: » Head is engaged but presenting part is above +2 station » Rarely done

21. Vacuum versus Forceps Forceps » More maternal trauma » Minimal fetal trauma (bruising) Vacuum » Less maternal trauma » Potential for increased fetal trauma (subgaleal bleeding)

22. Mitivac vacuum

23. Episiotomy Used for abnormal second stage of labor Originally thought to protect perineum » Now thought to result in more 3 rd and 4 th degree extensions » More perineal pain ACOG recommends restricted use rather than routine use At UNC less that 3% of patients Mediolateral episiotomy preferable to median due to higher rate of anal sphincter injury

24. Third Stage Disorders Retained placenta Uterine rupture Post-partum hemorrhage

25. Postpartum Hemorrhage Diagnosis » > 500 mL for vaginal birth » > 1000 mL for C/S Causes » Uterine atony » Placenta problem » Laceration Treatment » Pitocin » Cytotec » Hemabate » Methergine

26. Fourth Stage Disorders Bonding Delayed postpartum hemorrhage

27. Complications of abnormal labor Maternal »Chorioamnionitis »Post-partum hemorrhage »Operative vaginal delivery »Third/fourth degree perineal lacerations Fetal »Good neonatal outcomes after protracted first stage »Prolonged second stage not an independent risk factor for neonatal morbidity either

28. Shoulder Dystocia It cannot be predicted or prevented Associated with prolonged second stage Conditions that are associated with shoulder dystocia » Multiparity » Macrosomia » Prior episode of shoulder dystocia Associated with brachial plexus injuries » Most cases resolve without disability » Less than 2% brachial plexus injuries will be permanent

29. Shoulder Dystocia A subjective clinical diagnosis Diagnosis » Delivered fetal head retracts against maternal perineum (“turtle sign”) When suspected, goal is to intervene before asphyxia Management – disimpact the shoulder » McRoberts maneuver – application of suprapubic pressure Not fundal pressure as this may worsen impaction » Zavanelli maneuver – fetal head flexed and re-inserted into vagina » Intentional fracture of clavicle » There are several other maneuvers. There have been no RCTs comparing maneuvers. No maneuver is clearly superior than the other.

31. Ritgen Maneuver Erb’s palsey

32. Breech Presentation Occurs in 2% of singleton pregnancies Occurs more frequently in second and early third trimesters Conditions that are associated with breech presentation » Multiple gestation » Polyhydramnios » Anencephaly » Uterine anomalies Diagnosed with Leopold maneuvers, pelvic examination, U/S Morbidity and mortality for both the mother and fetus is higher is fetus is breech

33. Frank breech Complete breech Incomplete breech 3 Kinds of Breech Presentation

34. Management of Breech Presentation External cephalic version – applying pressure to abdomen to turn fetus in a forward or backward somersault Successful 50% of the time » Selection Criteria Preferred candidates have completed 37 weeks gestation » Risks Rupture of membranes Placental abruption Uterine rupture » Procedure Tocolysis with terbutaline Cesarean delivery Vaginal delivery

36. Cesarean Delivery

37. Umbilical Cord Prolapse A rare (<1%) emergency » Can compromise blood flow to fetus The cord descends alongside or beyond the fetal presenting part Possible etiologies » Fetomaternal: malpresentation, low birth weight, multiple gestation, polyhydramnios » Iatrogenic obstetrical interventions

38. Umbilical Cord Prolapse Diagnosis »Sudden, sever, prolonged bradycardia or decelerations »Overt – palpable upon vaginal examination »Occult – confirmed after cesarean delivery Management »Immediate cesarean birth »Temporizing measures Manual elevation of presenting part Bladder filling

39. Trial of Labor after Cesarean (TOLAC) The decision for TOLAC v. scheduled cesarean delivery is made using clinical judgement and shared decision- making. Risks »Uterine rupture »Peripartum hysterectomy (may be due to uterine rupture or placenta accreta) »Hemorrhage »Transfusion »Infection »Neonatal morbidity and mortality Benefits »Avoid risks associated with cesarean delivery

40. VBAC/Trial of Labor One previous LTCS (1% rate of rupture) Two previous LTCS (2% rupture) Unknown incision (up to 7% rupture) Success of TOLAC = VBAC (vaginal birth after cesarean section): 60 – 80%

41. TOLAC Candidates Factors to consider: »Prior vaginal birth »Spontaneous labor »Bishop score »Fetal weight »Prior uterine incisions (number and type)

42. USA TRENDS

43. Bottom Line Concepts Historically, the Friedman curve has been accepted as the standard assessment of the normal progression of labor Abnormal labor includes both arrest and protraction disorders Dystocia results from problems with “power” (uterine contractions), “passenger” (size, position, presentation) and “passage” (pelvis) The Bishop score can be used to determine whether or not a patient has a favorable cervix for augmentation of labor. Oxytocin can be administered to augment labor. For arrest of the second stage of labor, intervention is not indicated as long as fetal heart rate pattern is reassuring Shoulder dystocia cannot be predicted or prevented, so, obstetricians must be able to quickly recognize it and intervene promptly Umbilical cord prolapse is a rare obstetrical emergency Candidates for TOLAC should be chosen carefully based on history. Providers should also engage in shared decision-making, explaining the risks and benefits.