Answers
181. The answer is c.(Cunningham, pp 420-424, 484.)Patient has normal and adequate labor; no intervention is needed at this time. The patient is not completely dilated, so pushing is not warranted and it can cause cervi- cal lacerations and swelling. Epidural analgesia has not been shown to affect active labor, so stopping it will not make labor progress more quickly.
182. The answer is c.(Cunningham, pp 498-500.)The patient has a pro- tracted active phase of labor (cervical dilation < 1.2 cm/h). Either expectant management or Pitocin augmentation may be used for treatment. There is no arrest of descent at this time, and cesarean delivery is not warranted.
Amnioinfusion is not indicated for early decelerations. It may decrease the need for cesarean delivery in patients with variable or prolonged decelera- tions. Terbutaline would cause uterine relaxation and is not indicated.
183. The answer is b.(Hankins, pp 129-130, 137-138.)In the late 1980s and early 1990s, the classic definitions of forceps deliveries were slightly altered to conform with obstetric reality and the need for realistic definitions of procedures vis-á-vis both medical and legal guidelines and standards.
Outlet forceps delivery requires a visible scalp, the fetal skull on the pelvic floor, the sagittal suture in essentially OA position, and the fetal head on the perineum. A rotation can occur, but only up to 45°. A low forceps delivery requires a station of at least +2, but not on the pelvic floor. Rotation can be more than 45°. Midforceps delivery is from a station above +2, but with an engaged head. High forceps delivery, for which there are no modern indica- tions, would reflect a head not engaged.
184. The answer is d.(ACOG Committee Opinion 279.)Group B strepto- cocci (GBS), or Streptococcus agalactiae,has emerged as an important cause of perinatal morbidity and mortality. The gram-positive organism can colonize
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the lower gastrointestinal tract, and secondary spread to the genitourinary tract is common. Between 10% and 30% of pregnant women are colonized with GBS in the vagina or rectum. Routine prenatal screening is recom- mended between 35 and 37 weeks. Penicillin remains the agent of choice for intrapartum prophylaxis. Ampicillin is an acceptable alternative, but peni- cillin is preferred. However, data also show that GBS isolates are increasingly resistant to second-line therapies. Up to 15% of GBS isolates are resistant to clindamycin and 7% to 25% of isolates are resistant to erythromycin. This pattern of resistance has led to a change in the recommendations for second- line therapies. If penicillin allergic, but not at high risk for anaphylaxis, cefa- zolin is recommended. If penicillin allergic and high risk for anaphylaxis, use clindamycin or erythromycin if isolate is susceptible. If penicillin allergic and high risk for anaphylaxis and GBS resistant to clindamycin or erythromycin, or susceptibilities not available, use vancomycin.
185. The answer is e.(Cunningham, pp 488-491. Dewan and Hood, pp 3-5.) Aspiration pneumonitis is the most common cause of anesthetic-related death in obstetrics. Its occurrence may be minimized by reducing both the volume and acidity of gastric contents, which is often difficult in the patient in labor whose stomach is extremely slow to empty. All obstetric patients should be intubated for general anesthesia by a skilled professional. Extu- bation must be accomplished only after the patient is fully conscious and recumbent with her head turned to the side and lowered below the level of her chest. A woman who aspirates may develop evidence for respiratory dis- tress immediately to several hours after the incident. Decreased oxygen sat- uration, along with tachypnea, bronchospasm, rhonchi, rales, atelectasis, cyanosis, tachycardia, and hypotension, can develop. Intubation should be done by skilled personnel with cricoid pressure (Sellick maneuver).
186. The answer is b.(Cunningham, pp 506-508.)In the event of a face presentation, successful vaginal delivery will occur; the majority of the time with an adequate pelvis. Spontaneous internal rotation during labor is required to bring the chin to the anterior position, which allows the neck to pass beneath the pubis. Therefore, the patient is allowed to labor spon- taneously; a cesarean section is employed for failure to progress or for fetal distress. Manual conversion to vertex, forceps rotation, and internal ver- sion are no longer employed in obstetrics to deliver the face presentation because of undue trauma to both the mother and the fetus.
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187. The answer is d.(Scott, pp 438-444.)The labor portrayed is charac- teristic of a secondary arrest of dilation. The woman has entered the active phase of labor, as she previously progressed from 4 to 7 cm in less than 2 hours and then remains 7 cm over an additional 2 hours. The multiparous woman normally progresses at a rate of at least 1.5 cm/h (and the nullipara at least 1.2 cm/h) in the active phase. Dilation at a slower rate is a protraction disorder. Primary dysfunction, prolonged latent phase, and hypertonic dys- function occur prior to the active phase. The best evidence available indicates that this labor is hypotonic. Since the ultrasound indicates a fetus without obvious abnormalities, and since the patient’s previous infants were larger than this one, we assume the absence of cephalopelvic disproportion (CPD).
Oxytocin is the treatment of choice. If CPD were suspected, then the treat- ment preferred by many obstetricians would be cesarean section.
188. The answer is c.(Scott, pp 438-444.) The best evidence available indicates that this labor is hypotonic and that the contractions are inade- quate. Two contractions of 40 mm Hg intensity during a 10-minute period equates to 80 MUV. About 200 MUV are needed to consider contractions to be adequate to effect delivery. Since the ultrasound indicates a fetus without obvious abnormalities and smaller than her first infant, we assume the absence of cephalopelvic disproportion (CPD). Oxytocin is the treat- ment of choice in this situation. If CPD were suspected, then the treatment preferred by many obstetricians would be cesarean section.
189. The answer is e. (Hankins, pp 106-122.)Midline episiotomies are easier to fix and have a smaller incidence of surgical breakdown, less pain, and lower blood loss. The incidence of dyspareunia is somewhat less.
However, the incidence of extensions of the incision to include the rectum is considerably higher than with mediolateral episiotomies. Regardless of technique, attention to hemostasis and anatomic restoration is the key ele- ment of a technically appropriate repair.
190. The answer is d.(Cunningham, pp 817-819.)The patient described in the question presents with a classic history for abruption—that is, the sud- den onset of abdominal pain accompanied by bleeding. Physical examina- tion reveals a firm, tender uterus with frequent contractions, which confirms the diagnosis. The fact that a clot forms within 4 minutes suggests that coag- ulopathy is not present. Because abruption is often accompanied by hemor- rhaging, it is important that appropriate fluids (ie, lactated Ringer solution
and whole blood) be administered immediately to stabilize the mother’s cir- culation. Cesarean section may be necessary in the case of a severe abrup- tion, but only when fetal distress is evident or delivery is unlikely to be accomplished vaginally. Internal monitoring equipment should provide an early warning that the fetus is compromised. The internal uterine catheter provides pressure recordings, which are important if oxytocin stimulation is necessary. Generally, however, patients with abruptio placentae are con- tracting vigorously and do not need oxytocin.
191 to 193. The answers are 191-d, 192-b, 193-a. (Cunningham, pp 498-500.)A woman who has been dilated 9 cm for 3 hours is experi- encing a secondary arrest in labor. The deteriorating fetal condition (as evi- denced, eg, by late decelerations and falling scalp pH) dictates immediate delivery. A forceps rotation would be inappropriate because the cervix is not fully dilated. Cesarean section would be the safest and most expedi- tious method. Classic cesarean section is rarely used now because of greater blood loss and a higher incidence in subsequent pregnancies of rupture of the scar prior to labor. The best procedure would be a low transverse cesarean section. According to some studies, 25% of twins are diagnosed at the time of delivery. Although sonography or radiography can diagnose multiple gestations early in pregnancy, these methods are not used rou- tinely in all medical centers. The second twin is probably the only remain- ing situation where internal version is permissible. Although some obstetricians might perform a cesarean section for a second twin present- ing as a footling or shoulder, fetal bradycardia dictates that immediate delivery be done, and internal podalic version is the quickest procedure.
A transverse lie is undeliverable vaginally. One treatment option is to do nothing and hope that the lie will be longitudinal by the time labor com- mences. The only other appropriate maneuver would be to perform an external cephalic version. This maneuver should be done in the hospital, with monitoring of the fetal heart. If the version is successful and the cervix is ripe, it might be best to take advantage of the favorable vertex position by rupturing the membranes at that point and inducing labor.
194. The answer is b.(Cunningham, pp 452, 498-500.)The multiparous patient is in prolonged latent phase, characterized by painful uterine con- tractions without significant progression in cervical dilation. Prolongation of the latent phase is defined as 20 hour in nulliparous and 14 hour in multi- parous. The diagnosis of this category of uterine dysfunction is difficult
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and is made in many cases only in retrospect. Only rarely is there need to resort to oxytocic agents or to cesarean section. The recommended manage- ment is meperidine (Demerol) 100 mg intramuscularly; this will allow most patients to rest and wake up in active labor. About 10% of patients will wake up without contractions and the diagnosis of false labor will be made. Only about 5% of patients will wake up after meperidine in the same state of con- tractions without progression. Epidural block may lead to abnormal labor patterns and to delay of descent of the presenting part.
195. The answer is c. (Cunningham, pp 452, 498-500.) This protracted labor is associated with hypotonic uterine dysfunction, a condition that may have been exacerbated by the epidural block. If not contraindicated by other factors (eg, uterine scar), augmentation of labor by intravenous oxy- tocin is the treatment of choice in this situation.
196. The answer is e.(Cunningham, pp 452, 498-500.)The patient with arrest of descent and secondary arrest of dilation has adequate uterine con- tractions. Thus there is no reason to attempt to augment these contractions by oxytocin. The small-framed mother and the relatively large fetus may suggest cephalopelvic disproportion (CPD). Arrest disorders, common in CPD, and the absence of head engagement despite cervical dilation also support this diagnosis. The safest way to deliver such a baby would be cesarean section. Early decelerations occur before the onset of the contrac- tion and represent a vagal response to increased intracranial pressure from uterine pressure on the fetal head.
197 to 200. The answers are 197-d, 198-a, 199-c, 200-d.(Cunningham, pp 477-489.)Pudendal block is perhaps the most common form of anes- thesia used for vaginal delivery. It provides adequate pain relief for epi- siotomy, spontaneous delivery, forceps delivery, or vacuum extraction. The success of a pudendal block depends on a clear understanding of the anatomy of the pudendal nerve and its surroundings. Complications (vagi- nal hematomas, retropsoas, or pelvic abscesses) are quite rare. Paracervical block was a popular form of anesthesia for the first stage of labor until it was implicated in several fetal deaths. It has been shown that paracervical block was associated with fetal bradycardia in 25% to 35% of cases, prob- ably the response to rapid uptake of the drug from the highly vascular paracervical space with a resultant reduction of uteroplacental blood flow.
Death in some cases was related to direct injection of the local anesthetic
into the fetus. Low spinal anesthesia (saddle block) provides prompt and adequate relief for spontaneous and instrument-assisted delivery. The local anesthetic is injected at the level of the L4-5 interspace with the patient sit- ting. Although this method is intended to anesthetize the saddle area, the level of anesthesia may sometimes reach as high as T10. Hypotension and a decrease in uteroplacental perfusion are common results of the profound sympathetic blockade caused by spinal anesthesia. Epidural anesthesia provides effective pain relief for the first and second stages of labor and for delivery. It may be associated with late decelerations suggestive of utero- placental insufficiency in as many as 20% of cases, but the frequency of this complication may be reduced by prehydration of the mother and by avoid- ing the supine position. Epidural block appears to lengthen the second stage of labor and is associated with an increased need for augmentation of labor with oxytocin and for instrument-assisted delivery. In experienced hands, however, epidural anesthesia has an excellent safety record.
201 and 202. The answers are 201-c, 202-a. (Beckmann, pp 96-104.) This patient is most likely experiencing false labor, or Braxton-Hicks con- tractions. False labor is characterized by contractions that are irregular in timing and duration and do not result in any cervical dilation. The intensity of false labor does not change and the discomfort is mainly felt in the lower abdomen and is usually relieved by sedation. In the case of true labor, the uterine contractions occur at regular intervals and tend to become increas- ingly more intense with time. In true labor, the contractions tend to be felt in the patient’s back and abdomen, and cervical change occurs over time.
Sedation does not stop the discomfort. Active labor occurs when the cervix has reached about 4 cm and there are regular uterine contractions that rapidly dilate the cervix with time. The first stage of labor is the interval between the onset of labor and full cervical dilation. The second stage of labor begins with complete cervical dilation and ends with the delivery of the infant. The latent phase of labor is part of the first stage of labor; it encompasses cervical effacement and early dilation. Since this patient is not in true labor, the best plan of management is to send her home.
203. The answer is d.(Cunningham, pp 477-491.)The most appropriate modality for pain control in this patient is administration of an epidural block. An epidural block provides relief from the pain of uterine contrac- tions and delivery. It is accomplished by injecting a local anesthetic agent into the epidural space at the level of the lumbar intervertebral space.
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An indwelling catheter can be left in place to provide continuous infusion of an anesthetic agent throughout labor and delivery via a volumetric pump. When delivery is imminent, as in the case of this patient, a rapidly acting agent can be administered through the epidural catheter to effect perineal anesthesia. In this patient, intramuscular narcotics such as Demerol or morphine would not be preferred because these agents can cause respiratory depression in the newborn if delivery is imminent.
A pudendal block involves local infiltration of the pudendal nerve, which provides anesthesia to the perineum for delivery but no pain relief for uter- ine contractions. A local block refers to infusing a local anesthetic to the area of an episiotomy. The inhalation of anesthetic gases (general anesthesia) is reserved primarily for situations involving emergent cesarean sections and difficult deliveries. All anesthetic agents that depress the maternal CNS cross the placenta and affect the fetus. In addition, a major complication of gen- eral anesthesia is maternal aspiration, which can result in fatal aspiration pneumonitis.
204. The answer is c.(Cunningham, pp 498-500. Beckmann, pp 97, 100- 103.)Arrest of labor cannot be diagnosed during the first stage of labor until the cervix has reached 4 cm dilation and until adequate uterine contrac- tions (both in frequency and intensity) have been documented. The actual pressure within the uterus cannot be measured via an external tocody- namometer; an IUPC needs to be placed. It is generally accepted that 200 MUV (number of contractions in 10 minutes×average contraction inten- sity in mm Hg) are required for normal labor progress. A fetal scalp elec- trode would need to be placed in cases where the fetal heart rate tracing is difficult to monitor externally. A cesarean section would need to be per- formed once arrest of labor is diagnosed. Augmentation with Pitocin would be indicated if inadequate uterine contractions are diagnosed via the IUPC.
The epidural would need to be rebolused if the patient requires additional pain relief.
205. The answer is a. (Cunningham, pp 498-500, 519-520. Beckmann, pp 105-107.)The patient is having adequate uterine contractions as deter- mined by the intrauterine pressure catheter. Therefore, augmentation with Pitocin is not indicated. The patient’s diagnosis is secondary arrest of labor, which requires cesarean section. In the active phase of labor, a multiparous patient should undergo dilation of the cervix at a rate of at least 1.5 cm/h if uterine contractions are adequate. There is no indication for the use of
vacuum or forceps in this patient because the patient’s cervix is not com- pletely dilated and the head is unengaged. Assisted vaginal delivery with vacuum or forceps is indicated when the patient is completely dilated, to augment maternal pushing when maternal expulsive efforts are insufficient to deliver the fetus. It is not recommended to continue to allow the patient to labor if dystocia is diagnosed, because uterine rupture is a potential complication.
206. The answer is b.(Cunningham, pp 484-485. Beckmann, pp 109-115.) Prolonged fetal heart rate decelerations are isolated decelerations lasting 2 minutes or longer, but less than 10 minutes from onset to return to base- line. Epidural analgesia is a very common cause of fetal heart rate decelera- tions because it can be associated with maternal hypotension and decreased placental perfusion. Therefore, maternal blood pressure should always be noted in cases of fetal heart rate decelerations. If maternal blood pressure is abnormally low, ephedrine can be given to correct the hypotension. Because an umbilical cord prolapse can be associated with decelerations, the patient should undergo a cervical examination. In addition, the Pitocin infusion should be stopped because hyperstimulation of the uterus can be a cause of fetal hypoxia. The patient should be turned to the left lateral position to decrease uterine pressure on the great vessels and enhance uteroplacental flow. Supplemental oxygen should be given to the patient in an attempt to increase oxygen to the fetus. Only if the heart rate deceleration persists is a cesarean section performed.
207. The answer is a.(Cunningham, p 517.)In this clinical scenario, a shoulder dystocia is encountered. A shoulder dystocia occurs when the fetal shoulders fail to spontaneously deliver secondary to impaction of the anterior shoulder against the pubic bone after delivery of the head has occurred. Shoulder dystocia is an obstetric emergency and one should always call for help when such a situation is encountered. A generous episiotomy should always be made to allow the obstetrician to have ade- quate room to perform a number of manipulations to try to relieve the dys- tocia. Such maneuvers include the following: suprapubic pressure, McRoberts maneuver (flexing maternal legs upon the abdomen), Wood’s corkscrew maneuver (rotating the posterior shoulder), and delivery of the posterior shoulder. There is no role for fundal pressure because this action further impacts the shoulder against the pubic bone and makes the situa- tion worse. A Zavanelli maneuver is replacement of the fetal head into the
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