Normal Labor and Delivery

Questions

DIRECTIONS (Questions 1 through 34): For each of the multiple choice questions in this section, select the lettered answer that is the one best response in each case.

1. At term, the ligaments of the pelvis change. This may result in which of the following to aid fetal passage?

(A) a slight increase in the rotation of the femoral shaft (B) transient degeneration of pelvic ground substance (C) inferior placed angle to the iliosacral ligament (D) mild enlargement of the pelvic cavity

(E) posterior rotation of the levator muscles allowing improved fetal passage Questions 2 and 3 apply to the following patient:

A 4 ft 11 in Southeast Asian woman has an estimated fetal weight by ultrasound of 4,000 g. To estimate the pelvic capacity, you perform clinical pelvimetry.

2. Which of the following does this procedure measure?

(A) true conjugate

(B) transverse diameter of the inlet (C) shape of the pubic arch

(D) flare of the iliac crests

(E) elasticity of the levator muscles

3. You estimate that the pelvic outlet is adequate, but there may be a problem in the midpelvis. The interspinous diameter of a normal pelvis should be at least how many centimeters?

(A) 5 (B) 6–8 (C) 9–11 (D) 12

(E) The interspinous diameter is not a clinically important assessment

4. To appreciate how different positioning of the presenting part can impact the second stage of labor, one needs to understand the pelvic axis. During the delivery, the fetal head follows the pelvic axis. What is the best way to describe this axis?

(A) a straight line in parallel to the vaginal canal (B) a curve first directed anteriorly and then caudad (C) a curve first directed posteriorly and then caudad (D) a curve first directed posteriorly and then cephalad (E) a straight line perpendicular to the vaginal canal

5. The position of fetal presentation has a large impact on the success of the second stage of labor. The diagram in Figure 10–1 depicts which position of the fetus in the female pelvis?

Figure 10–1.

(A) right occipitoposterior (ROP) (B) left mentotransverse (LMT) (C) left occipitoanterior (LOA) (D) left sacrotransverse (LST) (E) left occiput transverse (LOT)

Questions 6 and 7 apply to the following patient:

You are counseling an extremely anxious 37-year-old primigravida who admits that she is “into control.”

She has researched analgesia in labor and has a few more questions about pudendal nerves.

6. The pudendal nerve can be easily blocked by local anesthetics. What does the neurological effect of the pudendal nerve block affect?

(A) the levator ani muscle

(B) the obturator internus muscle (C) sensation to the uterus

(D) motor innervation of the bladder (E) sensory innervation of the perineum

7. A pudendal anesthetic blockade accomplishes its effects through which of the following nerves?

(A) autonomic motor pathways (B) autonomic sensory pathways (C) T11, 12

(D) L2, 3, 4 (E) S2, 3, 4

8. When repairing a perineal laceration, what is the optimal suture to use because of healing time and least pain and inflammation produced?

(A) Dexon (polycaprolate) (B) plain catgut

(D) monocryl (poliglecaprone) (E) polydioxanone (PDS)

9. Which of the following is the major problem associated with the administration of barbiturates during labor?

(A) sudden fetal death

(B) fetal depression after birth

(C) lack of maternal cooperation during the birth process because of narcosis (D) the likelihood of maternal aspiration causing pneumonitis

(E) their effect is not better than placebo

10. It is important to be able to estimate the blood loss at a delivery to determine if more aggressive

management of uterine bleeding is indicated. Average blood loss during normal deliveries is how many milliliters?

(A) 700 (B) 500 (C) 250 (D) 100 (E) 50

11. During an obstructive labor, a retraction ring can form on the uterus that can compound the lack of progress in labor. Where does the physiologic retraction ring occur?

(A) internal os (B) external os

(D) junction of the upper and lower uterine segments (E) at the level of the tubal ostia

12. In a cephalic presentation, the position is determined by the relationship of what fetal part to the mother’s pelvis?

(A) mentum (B) sacrum (C) acromion (D) occiput (E) sinciput

13. The relation of the fetal parts to one another determines which of the following?

(A) presentation of the fetus (B) lie of the fetus

14. A primigravid patient has been having a long prodromal labor but has finally entered active phase of Stage 1. She is excited and wants to know what she should expect as a typical labor course. Average durations of active labor without epidural analgesia are best expressed by which of the following?

(A) first stage, 750 minutes; second stage, 80 minutes; third stage, 30 minutes

(B) first stage, 80 minutes; second stage, 20 minutes; third stage, 5 minutes (C) first stage, 120 minutes; second stage, 80 minutes; third stage, 5 minutes (D) first stage, 80 minutes; second stage, 20 minutes; third stage, 20 minutes (E) first stage, 750 minutes; second stage, 80 minutes; third stage, 5 minutes

15. A patient has failed to have any further dilation after achieving 6 cm. As possible reasons for this secondary arrest of dilation are explored, you place an intrauterine catheter to calculate the intensity of her contractions which are measured in Montevideo units. Which of the following is a Montevideo unit?

(A) number of contractions in 10 minutes

(B) number of contractions per minute times their intensity

(C) intensity of any 10 contractions times the time it took for them to occur (D) number of contractions over 50 mm Hg in 10 minutes

(E) number of contractions in 10 minutes times their average intensity

16. In the normal labor, the pressure produced by uterine contractions is greatest at which of the following times?

(A) latent phase (B) active phase (C) second stage (D) third stage

(E) when Braxton Hicks’ sign is evident

17. At 39 weeks during a pelvic examination, due to Braxton Hicks contractions, the patient is found to be 2 cm dilated. She asks if anything can be done to promote labor since she is exhausted from days of B H contractions. A sweeping (stripping) of the membranes is done based on the idea that this disrupts the lysosomes in the lower decidual. Which of the following, when released from lysosomes, may initiate labor?

(A) arachidonic acid (B) phosphatidylinositol (C) phospholipase A (D) thromboxane

(E) phosphatidylglycerol

18. Engagement is best defined as which of the following?

(A) when the presenting part goes through the pelvic inlet (B) when the presenting part is level with the ischial spines

(C) when the greatest biparietal diameter of the fetal head passes the pelvic inlet (D) when the greatest biparietal diameter of the head is level with the ischial spines

(E) when the greatest diameter of the fetal presenting part passes through the narrowest and lowest part of the maternal pelvis

19. A patient is experiencing an arrest of decent. During the evaluation one can feel that it is a vertex presentation with the sagittal suture transverse or oblique but closer to the symphysis than the promontory. What is this specific condition called?

(A) posterior asynclitism (B) internal rotation

(E) restitution

20. When educating a patient about the possible signs of labor you mention “bloody show.” This is which of the following?

(A) a result of small placental abruptions (B) not seen in breech presentations

(E) problematic in Rh-negative mothers if not given RhoGAM within 72 hours

21. A patient is being evaluated for excessive postpartum vaginal bleeding after a successful VBAC (vaginal birth after C-section) of a 3,500-g infant. One concern is retained placental tissue. Placental separation is facilitated by which of the following?

(A) deep placental growth into the myometrium (B) presence of a layer of decidua

(D) the changing configuration of the uterus after fetal delivery (E) bleeding into the uterus

22. Eight minutes after a normal delivery under pudendal anesthesia, the patient has not completed the third stage of labor. The uterus is discoid and firm; no bleeding is evident. What should you do?

(A) pull steadily but with greater traction on the cord (B) perform Crede’s maneuver

(E) gently massage the uterus and wait

23. A 20-year-old G1P0 patient is having a protracted active phase with irregular contractins that appear to be of inadequate intensity. It is determined that the patient would benefit from oxytocin (pitocin) augmentation. The patient is very nervous about this and asks a number of questions about the drug.

Which of the following is a characteristic of oxytocin?

(A) half-life of about 8 minutes (B) prolonged effect

(E) inhibited by nonsteroidal anti-inflammatory agents

24. A 21-year-old primiparous patient arrives in Labor and Delivery with poor prenatal care, her last visit being 8 weeks ago. She is 41 weeks by dates, and states she ruptured membranes approximately 12 hours ago. On examination, estimated weight is 9 lb. She has thick meconium. Her cervix is 3 cm, dilated, and the presenting part is at –2 station. The presenting part is a face. The fetal heart tones are excellent; she is not contracting. What is the best management?

(A) oxytocin induction with group B strep prophylaxis (B) Misoprostol 25 μg, group B strep prophylaxis

(D) epidural anesthesia to relax the pelvis, group B strep prophylaxis, and then oxytocin (E) cesarean section

Questions 25 and 26 apply to the following patient:

A 21-year-old primigravida at 39 weeks’ gestation presents to labor and delivery with complaints of uterine contractions since 5 AM that day. She is seen for a routine clinic visit at 3 PM and her cervix is found to be 2 cm dilated, 50% effaced, midposition, and moderate in consistency, with the fetal vertex at 0 station. Reexamination on labor and delivery at 7 PM shows no significant cervical change. Fetal heart tones are reassuring. She begs you to admit and augment her because she is tired of being pregnant. You explain that she and the fetus are doing well and that her Bishop’s score predicts the likelihood of a successful labor augmentation.

25. What is this gravida’s Bishop score?

(A) 8, cervix unripe (B) 4, cervix unripe (C) 2, cervix ripening (D) 6, cervix ripening (E) 9, cervix ripe

26. What would be the optimal obstetrical management at that time?

(A) labor augmentation with a high dose of oxytocin

(B) performance of primary cesarean section for prolonged labor with presumed cephalopelvic disproportion

(E) cervical ripening with misoprostol

Questions 27 and 28 apply to the following patient:

A 32-year-old woman (gravida 3, para 1, abortus 1) at term is admitted in labor with an initial cervical examination of 6-cm dilatation, complete effacement, and the vertex at –1 station. Estimated fetal weight is 8 lb, and her first pregnancy resulted in an uncomplicated vaginal delivery of an 8-lb infant. After 2 hours, there is no cervical change. An intrauterine pressure catheter is placed. This shows three contractions in a 10-minute period, each with a strength of 40 mm Hg.

27. What is this abnormality of labor termed?

(A) prolonged latent phase (B) active-phase arrest (C) failure of descent (D) arrest of latent phase (E) protraction of descent

28. What is the best course of action at this time?

(A) wait 2 more hours and repeat the cervical examination (B) start oxytocin augmentation

(D) discharge the patient, instructing her to return when contractions become stronger

(E) therapeutic rest with analgesia and short-acting anti-anxiety medication

29. The routine use of midline episiotomy during delivery has been shown to do which of the following?

(A) prevent urinary stress incontinence in the fourth decade of life (B) decrease the incidence of fetal cranial molding

(D) increase the incidence of third- and fourth-degree lacerations

(E) prevent the development of a rectocele and uterine prolapsed postmenopausal

30. Normal labor is dependent on the unique aspects of the uterine smooth muscle. Which statement characterizes uterine muscle cells during normal labor?

(A) The muscle regains full strength between contractions.

(B) The entire uterus contracts simultaneously.

(D) They demonstrate a contractile sensitivity to oxytocin.

(E) Muscle cells return to the original length after contraction.

31. Which of the following statements most accurately describes postpartum hemorrhage?

(A) It is prevented primarily by the increased concentration of clotting factors in maternal blood.

(B) Grand multiparity is a risk factor.

(D) Changes in pulse and blood pressure are good early indicators of excessive blood loss.

(E) Placenta accreta is the most frequent cause.

32. A relative contraindication for induction of labor includes which of the following?

(A) prolonged pregnancy (B) severe pre-eclampsia

(D) previous myomectomy entering the uterine cavity at the fundus (E) prolonged rupture of membranes without labor

Questions 33 and 34 apply to the following patient:

A 19-year-old primigravida at term presents to labor and delivery reporting irregular contractions and rupture of membranes 21 hours prior to arrival. She has not received prenatal care but reports that her pregnancy was uncomplicated. She is afebrile, and electronic fetal monitoring is reactive with occasional mild variable decelerations.

33. Which method is the most sensitive test to confirm rupture of membranes?

(A) nitrazine test (B) vaginal pooling (C) pelvic examination (D) ferning

(E) Coombs’ test

34. Cervical examination reveals a dilatation of 3 cm, 50% effacement, -1 station, vertex presentation.

Spontaneous rupture of membranes is confirmed. What is the best course of action at this time?

(A) perform an immediate low transverse cesarean section

(B) start intravenous (IV) antibiotics for group B streptococcal (GBS) prophylaxis (C) begin an amnioinfusion

(D) conduct a contraction stress test (E) ambulate the patient

DIRECTIONS (Questions 35 through 42): The following group of questions is preceded by a list of lettered options. For each question, select the one lettered option that is most closely associated with it. Each lettered option may be used once, multiple times, or not at all.

Questions 35 through 38 (A) first stage of labor (B) second stage of labor (C) third stage of labor (D) effacement

(E) lightening

(F) fourth stage of labor (G) postpartum period (H) engagement

35. Dropping of the fetal head into the pelvis 36. Ends with complete dilation of the cervix 37. Begins with the delivery of the baby 38. Ends with the delivery of the baby Questions 39 through 42

(A) McRoberts maneuver

(B) Mauriceau-Smellie-Veit maneuver (C) external cephalic version

(D) Ritgen maneuver (E) Leopold’s maneuvers (F) Ferguson’s maneuver (G) Crede maneuver

(H) Wood’s corkscrew maneuver

39. At 39 weeks’ gestation, a woman is admitted to labor and delivery. Her cervix is long and closed.

The fetus is found to be a vertex presentation by palpation.

40. Gentle constant abdominal pressure is applied to cause the fetal vertex to rotate out of the fundal area and into the lower uterine segment.

41. The vertex delivers, but gentle downward traction fails to effect delivery of the anterior shoulder.

42. A rapid labor with a vertex presentation has taken place, and the infant is crowning. Mother is in poor control so attempts are made to slow the delivery of the vertex to avoid perineal/ vaginal lacerations.

DIRECTIONS (Questions 43 through 45): For each of the multiple choice questions in this section, select the lettered answer that is the one best response in each case.

Questions 43 through 45 apply to the following patient:

A 24-year-old G3P0 Ab 2 presents in early labor at 39 weeks. She has a prepregnancy BMI of 48. Her 1 hour 50 g glucose screen was 138 mg%. No 3 hour was ordered. An ultrasound last week noted an AFI of 24 cm. Normal is less than 20 cm. The fetus was noted to have extra fatty tissue around the body and has an estimated fetal weight of 4,300 g. The patient is very uncomfortable and can only sleep sitting up in a chair. Given the clinical situation an induction is started and 24 hours later she is in second stage of labor.

43. In anticipation of a possible postpartum hemorrhage due to the prolonged induction and macrosomia, which of the following options is best for the prevention of excess blood loss?

(A) oxytocin 10 units IM if bleeding exceeds 500 cc (B) type and cross 2 units of packed red blood cells

(E) 600 μg of prostaglandin E1 (misoprostol) given per rectum after delivery of the placenta

44. What is the best option in preparation for a possible shoulder dystocia given the fetal macroso-mia?

(A) check the mother’s glucose by finger stick every 2 hours (B) type and cross for 2 units packed red blood cells

(C) request extra attendants in the room for delivery to help with McRoberts maneuver (D) delivery in the operating room to facilitate emergency cesarean delivery if needed (E) epidural anesthesia so the mother can let the fetus labor down without the urge to push

45. If the patient has a cesarean delivery, during early postpartum recovery, what is the best level for her O2 saturation?

(A) no minimum O2 saturation as long as she has stable vital signs (B) 90%

(D) 96%

(E) the same as her predelivery O2 saturations

Answers and Explanations

1. (D) The change is one of relaxation of the ligaments, allowing more mobility at the sacroiliac and symphyseal joints and on occasion some instability. Whether or not these changes truly add to pelvic size has not been determined, but they seem to allow passage more easily, perhaps by accommodation.

2. (C) Clinical pelvimetry cannot directly measure the midplane of the pelvis, but its capacity can be estimated by the evaluation of the sacrosciatic notch, the ischial spines, and the concavity of the

sacrum. Parallel pelvic sidewalls and a wide pubic arch are crucial to the outlet evaluation. The pelvic inlet cannot be assessed by clinical pelvimetry.

3. (C) The interspinous diameter is the lateral distance between the ischial spines. The ischial spines should not be too prominent on pelvic examination. The distance is generally considered to be the smallest pelvic diameter and the “obstetric limit” in preventing or allowing delivery. Thus one wants it to be at least 9 to 11 cm.

4. (C) A common misconception is that the fetal head follows a straight line through the pelvis. On the contrary, it describes nearly a 90° angle following the pelvic axis. The pelvic axis (curve of Carus) reflects a line in the center of the pelvic inlet (directing it posterior into the sacrum), then caudally toward the center of the outlet (extending the head). The classic mechanisms of labor can be better understood through a knowledge of the pelvic axis.

5. (E) In vertex presentations, the relation of the occiput to the maternal pelvis determines the position.

The position of the occiput can be detected by finding the posterior fontanel. As it is on the left lateral side of the mother and the sagittal suture is transverse, the position is LOT.

6. (E) The pudendal block is often used for delivery or minor surgery on the vulva. The pudendal nerve can be blocked either transvagi-nally or percutaneously through the buttock. The latter route may be used in the presence of a Bartholin’s abscess without causing pain during vaginal manipulation.

7. (E) The pudendal nerve is blocked near the ischial spines. This block will not interfere with uterine contractions and will provide anesthesia to the perineum. Because there is considerable overlap of innervation, midline infiltration anterior to the rectum is needed to provide the best block.

8. (A) Suture to prepare perineal lacerations is chosen on pain produced as well as dissolving in a reasonable time—weeks not many months. Studies show that Dexon and Vicryl (undyed should be used) cause the least inflammation and least discomfort. PDS and Monocryl are not used because they take too long to absorb.

9. (B) Fetal depression is the best reason to minimize the use of barbiturates in labor. For example, after a dose of thiopental is given, it will reach the fetal circulation in 2 to 3 minutes. A dose of 250 mg will have little effect on an otherwise healthy infant, but it does have some effect. All the other distractors have been claimed. Remember, a barbiturate alone is a poor substitute for a true analgesic agent. It seldom is given in large enough doses to truly sedate or narcotize the mother, but when given with narcotics, it certainly can. Anesthetic and analgesic effects on the fetus are a never-ending source of controversy. There is no clear-cut “best” anesthetic or analgesic regimen for delivery. Judgment should

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