- Email: [email protected]
Maternal congenital diaphragmatic hernia complicating pregnancy
4. Hopkins EL, Hendricks CH, Cibils LA. Cerebrospinal fluid pressure in labor. Am J Obstet Gynecol 1965;93: 907–16. 5. Semple DA, McClure JH, Wallace EM. ArnoldChiari malformation in pregnancy. Anaesthesia 1996;51: 580–2. 6. Hullander RM, Bogard TD, Leivers D, Moran D, Dewan DM. Chiari I malformation presenting as recurrent spinal headache. Anesth Analg 1992;75:1025–6. 7. Nel MR, Robson V, Robinson PN. Extradural anaesthesia for Caesarean section in a patient with syringomyelia and Chiari type I anomaly. Br J Anaesth 1998;80:512–5.
Maternal Congenital Diaphragmatic Hernia Complicating Pregnancy Mehmet R. Genc, MD, PhD, Thomas E. Clancy, MD, Stephen J. Ferzoco, MD, and Errol Norwitz, MD, PhD Departments of Obstetrics and Gynecology and Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
BACKGROUND: Symptomatic maternal diaphragmatic hernia in a pregnant woman is a surgical emergency associated with high morbidity and mortality both for her and her fetus. Such patients are most commonly managed with immediate cesarean delivery combined with hernia repair. CASE: A woman presented at 29 weeks’ gestation with symptoms of bowel obstruction due to herniation of viscera through a previously undiagnosed congenital diaphragmatic hernia of Bochdalek, and she was stabilized. Antenatal corticosteroids were administered to facilitate fetal maturity. The hernia was repaired 10 days after her presentation because of evidence of incarceration. Labor was induced at 39 weeks’ gestation, and a healthy infant was delivered vaginally. CONCLUSION: Expectant management and vaginal delivery after antepartum repair of congenital diaphragmatic hernia in the mother is a reasonable alternative to immediate cesarean delivery. (Obstet Gynecol 2003;102:1194 – 6. © 2003 by The American College of Obstetricians and Gynecologists.)
Address reprint requests to: Mehmet R. Genc, MD, PhD, Bebekyokuso Sok 7 (Erdem Apt), D.6, Etiler, Istanbul, Turkey 80600; E-mail: [email protected].
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8. Penney DJ, Smallman JMB. Arnold-Chiari malformation and pregnancy. Int J Obstet Anesth 2001;10:139–41. 9. Barton JJS, Sharpe JA. Oscillopsia and horizontal nystagmus with accelerating slow phases following lumbar puncture in the Arnold-Chiari malformation. Ann Neurol 1993; 33:418–21. 10. Hilt H, Gramm H-J, Link J. Changes in intracranial pressure associated with extradural anaesthesia. Br J Anaesth 1986;58:676–80. Received October 3, 2002. Received in revised form January 28, 2003. Accepted January 30, 2003.
Maternal diaphragmatic hernia complicating pregnancy is a rarity. Diaphragmatic hernias are classified into three categories: paraesophageal (hiatal), congenital, and traumatic.1 In pregnancy, hiatal hernias are more common than the other types and result from increased intraabdominal pressure during the second and third trimesters. Congenital hernias are caused by defects in the diaphragm arising from faulty embryologic development in the posterolateral (Bochdalek) or the substernal (Morgagni) portion of the diaphragm. Traumatic diaphragmatic hernia results from blunt trauma, which increases intraabdominal pressure and tears diaphragmatic fibers. The main life-threatening complications of diaphragmatic hernia are acute dyspnea caused by compression atelectasis, mediastinal shift, and strangulation and gangrene of the herniated viscera.2 Traditionally, immediate repair has been undertaken if symptoms arise, because further delay might be fatal both to the mother and the fetus.1,2 For asymptomatic patients, Kurzel and Naunheim1 recommended cesarean delivery after fetal lung maturity is documented, with simultaneous hernia repair. They opposed vaginal delivery under any circumstance because of the notion that increased intraabdominal pressure during Valsalva maneuver when the patient is bearing down will further displace the viscera, which might result in incarceration with subsequent strangulation and obstruction. They based their recommendation on 17 cases reported in the English literature since 1928. In this case series, the maternal and fetal morbidity was as high as 55% and 27%, respectively, when vaginal delivery was attempted before the diaphragmatic hernia was repaired.1 In the literature, there are two reported cases of prenatal repair of a symptomatic foramen of Bochdalek hernia in the third trimester. In these cases, pregnancy was allowed to continue until 39 weeks’ gestation or fetal
VOL. 102, NO. 5, PART 2, NOVEMBER 2003 © 2003 by The American College of Obstetricians and Gynecologists. Published by Elsevier.
0029-7844/03/$30.00 doi:10.1016/S0029-7844(03)00680-X
lung maturity was established, at which time elective cesarean delivery was performed.1,3 In this report, we describe vaginal delivery after an antepartum repair of a foramen of Bochdalek hernia. CASE A 30-year-old, gravida 2, para 1, previously healthy woman presented to a local hospital at 29 weeks’ gestation with a 7-day history of unremitting nausea, vomiting, and intermittent sharp epigastric pain. Three years before this pregnancy, she had an uneventful pregnancy that ended in a vaginal delivery of a healthy infant at term. On physical examination, the patient was afebrile with stable vital signs. Her abdomen was soft and moderately tender over the epigastrium. Normal bowel sounds were auscultated. She had no signs or symptoms of respiratory compromise. Laboratory tests were remarkable only for a white blood count of 14,200/mL and elevated amylase and lipase levels of 130 and 97 IU/mL, respectively. A nasogastric tube was placed and returned 1400 mL bilious, nonbloody fluid. Maternal abdominal ultrasound was unremarkable, but the pancreas could not be visualized. No prior chest x-ray studies were available for review. An abdominal upright x-ray study revealed a large gastric air bubble and air–fluid levels projecting over the left side of the heart. Endoscopy of the upper gastrointestinal tract suggested paraesophageal hernia. Magnetic resonance imaging of the abdomen showed at least 50% of the stomach in the thorax (Figure 1). The patient was transferred to our tertiary care center for further management. Given her stable condition and reassuring fetal testing, we decided to continue expectant management. Intermittent suction through a nasogastric tube was continued to allow gastric decompression. Antacids were administered intravenously to prevent peptic ulcer disease. The patient was left nil per os, and total parenteral nutrition was started. Two doses of betamethasone, 12.5 mg intramuscularly, were given 24 h apart for fetal maturation. The levels of blood electrolytes, alanine and aspartate amino transaminase, total and direct bilirubin, as well as complete blood count were determined serially. Biophysical profile was assessed once per day to monitor fetal well-being. On hospital day 10, the patient complained of suddenonset intermittent substernal pain radiating to her left shoulder. Her heart rate was in the range of 100 to 106 beats per minute, but otherwise her vital signs were normal. Her white blood count was 22,800/mL. Other laboratory values were normal. Because of concerns for ischemia of the viscera, the decision was made to proceed with exploratory laparotomy.
VOL. 102, NO. 5, PART 2, NOVEMBER 2003
Figure 1. Magnetic resonance image demonstrating Bochdalek hernia with associated abdominal organs in the left chest. The arrow indicates the herniated portion of colon. Genc. Congenital Diaphragmatic Hernia. Obstet Gynecol 2003.
On exploration through an upper midline incision, more than half of the stomach and a 20-cm portion of the transverse colon were identified in the left hemithorax. The viscera had protruded upward through a 4 cm ⫻ 8 cm posterolateral foramen of Bochdalek diaphragmatic defect. The viscera were gently reduced to the abdomen without any difficulty. Inspection of the viscera showed no evidence of ischemic damage. The hernia sac was excised, and the defect in the diaphragm was repaired primarily with interrupted 0 polyester (Ethibond, Ethicon, Inc, Somerville, NJ) sutures. Manipulation of the uterus was avoided during surgery. A chest tube was placed in the left hemithorax. Fetal well-being was confirmed throughout the procedure by continuous fetal heart rate monitoring. Fetal heart rate and uterine activity were monitored postoperatively. Tocolysis with magnesium sulfate infusion was initiated because of uterine contractions occurring every 1–3 minutes and maintained for 48 h until uterine contractions ceased completely. The patient’s postoperative recovery was otherwise uncomplicated. The chest and nasogastric tubes were removed 2 days after surgery. The patient was discharged home on postoperative day 5 after she tolerated a regular diet. To avoid an unplanned delivery, the patient was admitted for induction of labor at 39 weeks’ gestation. Her cervix was closed and long. A prostaglandin E2
Genc et al
Congenital Diaphragmatic Hernia
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vaginal insert was administered for cervical ripening. Regional anesthesia was administered though an epidural catheter. The cervix dilated fully without oxytocin. To avoid an increase in intraabdominal pressure, which might cause rupture of the repaired diaphragmatic defect, the patient was asked not to bear down, and delivery was electively assisted with forceps. A live-born male infant was delivered with Apgar scores of 9 at 1 minute and 9 at 5 minutes. The patient’s postpartum course was uncomplicated. She was discharged home 2 days after delivery. COMMENT The management of a pregnant patient with symptomatic diaphragmatic hernia is challenging. This and other case reports1,3–5 demonstrate that diaphragmatic hernia can be repaired prenatally. Nevertheless, preterm delivery during or after surgery due to unstoppable preterm labor or nonreassuring fetal status is a concern. Therefore, antenatal corticosteroids for fetal maturity should be administered to the mother before the surgery if the gestational age is between 24 and 34 weeks, the mother’s condition is stable, and the surgery can be delayed. This and another report3 suggest that gastric decompression might improve the clinical condition of the pregnant patient with a diaphragmatic hernia who presents with symptoms and signs of obstruction. Such an improvement can allow the surgery to be delayed until the patient is transferred to a tertiary care center or until antenatal corticosteroids are administered. In these two cases, the clinical improvement was transient and lasted several days. Given this fact, a patient whose clinical condition improves after gastric decompression should be observed in the hospital until repair of her hernia. Surgery to repair diaphragmatic hernia should be undertaken if there is any suspicion of visceral incarceration. Alternatively, one might consider performing surgical repair after antenatal corticosteroids are administered and under elective conditions to avoid an emergency due to sudden deterioration in the patient’s condition or preterm labor. Uterine contractions, unlike the Valsalva maneuver, do not increase the intraabdominal pressure and are unlikely to cause rupture at the repaired site. Thus, a patient with a repaired diaphragmatic hernia can labor and deliver vaginally. There is no data on the minimum time that should elapse from hernia repair to delivery. Forceps or a vacuum extractor can be used to assist the
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Congenital Diaphragmatic Hernia
second stage of labor as a precautionary measure. This prevents the patient from bearing down and increasing her intraabdominal pressure. The patient’s urge to bear down could be overcome with adequate regional anesthesia (preferably epidural). Induction of labor at term should be considered to avoid an unplanned precipitous delivery at a remote site. The incidence of asymptomatic Bochdalek’s hernia in the adult population was reported to be at least 0.17%, with a female-to-male ratio of 17:5.6 Despite such a high incidence, the number of pregnancies complicated by unrecognized congenital diaphragmatic hernia is extremely small—34 cases, including this one, have been reported since 1928.2 Thus, routine repair of asymptomatic congenital diaphragmatic hernia in pregnant women or those contemplating childbearing is not warranted. Such women can be allowed to labor and deliver vaginally following the principles mentioned above. Furthermore, they should be closely followed antenatally and postpartum for signs of bowel obstruction and respiratory compromise, because delays in intervention in such instances have resulted in both maternal and fetal deaths.7,8 REFERENCES 1. Kurzel RB, Naunheim KS. Repair of symptomatic diaphragmatic hernia during pregnancy. Obstet Gynecol 1988; 71:869–71. 2. Kaloo PD, Studd R, Child A. Postpartum diagnosis of maternal diaphragmatic hernia. Aust N Z J Obstet Gynaecol 2001;41:461–3. 3. Fleyfel M, Provost N, Ferreira JF, Porte H, Bourzoufi K. Management of diaphragmatic hernia during pregnancy. Anesth Analg 1998;86:501–3. 4. Hobbins W, Hurwitz C. Incarcerated diaphragmatic hernia of the colon occurring during pregnancy. N Eng J Med 1953;249:773–4. 5. Fardy HJ. Vomiting in late pregnancy due to diaphragmatic hernia. Case report. Br J Obstet Gynaecol 1984;91:390–2. 6. Mullins ME, Stein J, Saini SS, Mueller PR. Prevalence of incidental Bochdalek’s hernia in a large adult population. AJR Am J Roentgenol 2001;177:363–6. 7. Fishback HR. A fenestra of the diaphragm. Arch Pathol 1928;6:867–70. 8. Diddle AW, Tidrick RT. Diaphragmatic hernia associated with pregnancy. Am J Obstet Gynecol 1941;41:317–21. Received December 6, 2002. Received in revised form January 30, 2003. Accepted February 19, 2003.
OBSTETRICS & GYNECOLOGY
Maternal Congenital Diaphragmatic Hernia Complicating Pregnancy Mehmet R. Genc, MD, PhD, Thomas E. Clancy, MD, Stephen J. Ferzoco, MD, and Errol Norwitz, MD, PhD Departments of Obstetrics and Gynecology and Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
BACKGROUND: Symptomatic maternal diaphragmatic hernia in a pregnant woman is a surgical emergency associated with high morbidity and mortality both for her and her fetus. Such patients are most commonly managed with immediate cesarean delivery combined with hernia repair. CASE: A woman presented at 29 weeks’ gestation with symptoms of bowel obstruction due to herniation of viscera through a previously undiagnosed congenital diaphragmatic hernia of Bochdalek, and she was stabilized. Antenatal corticosteroids were administered to facilitate fetal maturity. The hernia was repaired 10 days after her presentation because of evidence of incarceration. Labor was induced at 39 weeks’ gestation, and a healthy infant was delivered vaginally. CONCLUSION: Expectant management and vaginal delivery after antepartum repair of congenital diaphragmatic hernia in the mother is a reasonable alternative to immediate cesarean delivery. (Obstet Gynecol 2003;102:1194 – 6. © 2003 by The American College of Obstetricians and Gynecologists.)
Address reprint requests to: Mehmet R. Genc, MD, PhD, Bebekyokuso Sok 7 (Erdem Apt), D.6, Etiler, Istanbul, Turkey 80600; E-mail: [email protected].
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8. Penney DJ, Smallman JMB. Arnold-Chiari malformation and pregnancy. Int J Obstet Anesth 2001;10:139–41. 9. Barton JJS, Sharpe JA. Oscillopsia and horizontal nystagmus with accelerating slow phases following lumbar puncture in the Arnold-Chiari malformation. Ann Neurol 1993; 33:418–21. 10. Hilt H, Gramm H-J, Link J. Changes in intracranial pressure associated with extradural anaesthesia. Br J Anaesth 1986;58:676–80. Received October 3, 2002. Received in revised form January 28, 2003. Accepted January 30, 2003.
Maternal diaphragmatic hernia complicating pregnancy is a rarity. Diaphragmatic hernias are classified into three categories: paraesophageal (hiatal), congenital, and traumatic.1 In pregnancy, hiatal hernias are more common than the other types and result from increased intraabdominal pressure during the second and third trimesters. Congenital hernias are caused by defects in the diaphragm arising from faulty embryologic development in the posterolateral (Bochdalek) or the substernal (Morgagni) portion of the diaphragm. Traumatic diaphragmatic hernia results from blunt trauma, which increases intraabdominal pressure and tears diaphragmatic fibers. The main life-threatening complications of diaphragmatic hernia are acute dyspnea caused by compression atelectasis, mediastinal shift, and strangulation and gangrene of the herniated viscera.2 Traditionally, immediate repair has been undertaken if symptoms arise, because further delay might be fatal both to the mother and the fetus.1,2 For asymptomatic patients, Kurzel and Naunheim1 recommended cesarean delivery after fetal lung maturity is documented, with simultaneous hernia repair. They opposed vaginal delivery under any circumstance because of the notion that increased intraabdominal pressure during Valsalva maneuver when the patient is bearing down will further displace the viscera, which might result in incarceration with subsequent strangulation and obstruction. They based their recommendation on 17 cases reported in the English literature since 1928. In this case series, the maternal and fetal morbidity was as high as 55% and 27%, respectively, when vaginal delivery was attempted before the diaphragmatic hernia was repaired.1 In the literature, there are two reported cases of prenatal repair of a symptomatic foramen of Bochdalek hernia in the third trimester. In these cases, pregnancy was allowed to continue until 39 weeks’ gestation or fetal
VOL. 102, NO. 5, PART 2, NOVEMBER 2003 © 2003 by The American College of Obstetricians and Gynecologists. Published by Elsevier.
0029-7844/03/$30.00 doi:10.1016/S0029-7844(03)00680-X
lung maturity was established, at which time elective cesarean delivery was performed.1,3 In this report, we describe vaginal delivery after an antepartum repair of a foramen of Bochdalek hernia. CASE A 30-year-old, gravida 2, para 1, previously healthy woman presented to a local hospital at 29 weeks’ gestation with a 7-day history of unremitting nausea, vomiting, and intermittent sharp epigastric pain. Three years before this pregnancy, she had an uneventful pregnancy that ended in a vaginal delivery of a healthy infant at term. On physical examination, the patient was afebrile with stable vital signs. Her abdomen was soft and moderately tender over the epigastrium. Normal bowel sounds were auscultated. She had no signs or symptoms of respiratory compromise. Laboratory tests were remarkable only for a white blood count of 14,200/mL and elevated amylase and lipase levels of 130 and 97 IU/mL, respectively. A nasogastric tube was placed and returned 1400 mL bilious, nonbloody fluid. Maternal abdominal ultrasound was unremarkable, but the pancreas could not be visualized. No prior chest x-ray studies were available for review. An abdominal upright x-ray study revealed a large gastric air bubble and air–fluid levels projecting over the left side of the heart. Endoscopy of the upper gastrointestinal tract suggested paraesophageal hernia. Magnetic resonance imaging of the abdomen showed at least 50% of the stomach in the thorax (Figure 1). The patient was transferred to our tertiary care center for further management. Given her stable condition and reassuring fetal testing, we decided to continue expectant management. Intermittent suction through a nasogastric tube was continued to allow gastric decompression. Antacids were administered intravenously to prevent peptic ulcer disease. The patient was left nil per os, and total parenteral nutrition was started. Two doses of betamethasone, 12.5 mg intramuscularly, were given 24 h apart for fetal maturation. The levels of blood electrolytes, alanine and aspartate amino transaminase, total and direct bilirubin, as well as complete blood count were determined serially. Biophysical profile was assessed once per day to monitor fetal well-being. On hospital day 10, the patient complained of suddenonset intermittent substernal pain radiating to her left shoulder. Her heart rate was in the range of 100 to 106 beats per minute, but otherwise her vital signs were normal. Her white blood count was 22,800/mL. Other laboratory values were normal. Because of concerns for ischemia of the viscera, the decision was made to proceed with exploratory laparotomy.
VOL. 102, NO. 5, PART 2, NOVEMBER 2003
Figure 1. Magnetic resonance image demonstrating Bochdalek hernia with associated abdominal organs in the left chest. The arrow indicates the herniated portion of colon. Genc. Congenital Diaphragmatic Hernia. Obstet Gynecol 2003.
On exploration through an upper midline incision, more than half of the stomach and a 20-cm portion of the transverse colon were identified in the left hemithorax. The viscera had protruded upward through a 4 cm ⫻ 8 cm posterolateral foramen of Bochdalek diaphragmatic defect. The viscera were gently reduced to the abdomen without any difficulty. Inspection of the viscera showed no evidence of ischemic damage. The hernia sac was excised, and the defect in the diaphragm was repaired primarily with interrupted 0 polyester (Ethibond, Ethicon, Inc, Somerville, NJ) sutures. Manipulation of the uterus was avoided during surgery. A chest tube was placed in the left hemithorax. Fetal well-being was confirmed throughout the procedure by continuous fetal heart rate monitoring. Fetal heart rate and uterine activity were monitored postoperatively. Tocolysis with magnesium sulfate infusion was initiated because of uterine contractions occurring every 1–3 minutes and maintained for 48 h until uterine contractions ceased completely. The patient’s postoperative recovery was otherwise uncomplicated. The chest and nasogastric tubes were removed 2 days after surgery. The patient was discharged home on postoperative day 5 after she tolerated a regular diet. To avoid an unplanned delivery, the patient was admitted for induction of labor at 39 weeks’ gestation. Her cervix was closed and long. A prostaglandin E2
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Congenital Diaphragmatic Hernia
1195
vaginal insert was administered for cervical ripening. Regional anesthesia was administered though an epidural catheter. The cervix dilated fully without oxytocin. To avoid an increase in intraabdominal pressure, which might cause rupture of the repaired diaphragmatic defect, the patient was asked not to bear down, and delivery was electively assisted with forceps. A live-born male infant was delivered with Apgar scores of 9 at 1 minute and 9 at 5 minutes. The patient’s postpartum course was uncomplicated. She was discharged home 2 days after delivery. COMMENT The management of a pregnant patient with symptomatic diaphragmatic hernia is challenging. This and other case reports1,3–5 demonstrate that diaphragmatic hernia can be repaired prenatally. Nevertheless, preterm delivery during or after surgery due to unstoppable preterm labor or nonreassuring fetal status is a concern. Therefore, antenatal corticosteroids for fetal maturity should be administered to the mother before the surgery if the gestational age is between 24 and 34 weeks, the mother’s condition is stable, and the surgery can be delayed. This and another report3 suggest that gastric decompression might improve the clinical condition of the pregnant patient with a diaphragmatic hernia who presents with symptoms and signs of obstruction. Such an improvement can allow the surgery to be delayed until the patient is transferred to a tertiary care center or until antenatal corticosteroids are administered. In these two cases, the clinical improvement was transient and lasted several days. Given this fact, a patient whose clinical condition improves after gastric decompression should be observed in the hospital until repair of her hernia. Surgery to repair diaphragmatic hernia should be undertaken if there is any suspicion of visceral incarceration. Alternatively, one might consider performing surgical repair after antenatal corticosteroids are administered and under elective conditions to avoid an emergency due to sudden deterioration in the patient’s condition or preterm labor. Uterine contractions, unlike the Valsalva maneuver, do not increase the intraabdominal pressure and are unlikely to cause rupture at the repaired site. Thus, a patient with a repaired diaphragmatic hernia can labor and deliver vaginally. There is no data on the minimum time that should elapse from hernia repair to delivery. Forceps or a vacuum extractor can be used to assist the
1196
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Congenital Diaphragmatic Hernia
second stage of labor as a precautionary measure. This prevents the patient from bearing down and increasing her intraabdominal pressure. The patient’s urge to bear down could be overcome with adequate regional anesthesia (preferably epidural). Induction of labor at term should be considered to avoid an unplanned precipitous delivery at a remote site. The incidence of asymptomatic Bochdalek’s hernia in the adult population was reported to be at least 0.17%, with a female-to-male ratio of 17:5.6 Despite such a high incidence, the number of pregnancies complicated by unrecognized congenital diaphragmatic hernia is extremely small—34 cases, including this one, have been reported since 1928.2 Thus, routine repair of asymptomatic congenital diaphragmatic hernia in pregnant women or those contemplating childbearing is not warranted. Such women can be allowed to labor and deliver vaginally following the principles mentioned above. Furthermore, they should be closely followed antenatally and postpartum for signs of bowel obstruction and respiratory compromise, because delays in intervention in such instances have resulted in both maternal and fetal deaths.7,8 REFERENCES 1. Kurzel RB, Naunheim KS. Repair of symptomatic diaphragmatic hernia during pregnancy. Obstet Gynecol 1988; 71:869–71. 2. Kaloo PD, Studd R, Child A. Postpartum diagnosis of maternal diaphragmatic hernia. Aust N Z J Obstet Gynaecol 2001;41:461–3. 3. Fleyfel M, Provost N, Ferreira JF, Porte H, Bourzoufi K. Management of diaphragmatic hernia during pregnancy. Anesth Analg 1998;86:501–3. 4. Hobbins W, Hurwitz C. Incarcerated diaphragmatic hernia of the colon occurring during pregnancy. N Eng J Med 1953;249:773–4. 5. Fardy HJ. Vomiting in late pregnancy due to diaphragmatic hernia. Case report. Br J Obstet Gynaecol 1984;91:390–2. 6. Mullins ME, Stein J, Saini SS, Mueller PR. Prevalence of incidental Bochdalek’s hernia in a large adult population. AJR Am J Roentgenol 2001;177:363–6. 7. Fishback HR. A fenestra of the diaphragm. Arch Pathol 1928;6:867–70. 8. Diddle AW, Tidrick RT. Diaphragmatic hernia associated with pregnancy. Am J Obstet Gynecol 1941;41:317–21. Received December 6, 2002. Received in revised form January 30, 2003. Accepted February 19, 2003.
OBSTETRICS & GYNECOLOGY