Asia-Oceania J. Obstet. Cynaecol. Vol. 18, No. 4: 319-323 1992
A Case Report : Vesico-Rectal Fistula with Ano-Urethral Atresia
C. Anandakumar, Y. C. Wong, A. Biswas, A. Venkat, D. Chia, S. Arulkumaran, and S. S. Ratnam Division of Feto-Maternal Medicine, Department of Obstetrics and Oynaecology, National University Hospital, Singapore
Abstract Vesico-rectal fistula is a rare congenital abnormality causing severe early second trimester oligohydramnios. Prenatal diagnosis of such a case is reported here. Ultrasound diagnosis could be aided by transabdominal amnio-infusion and, if necessary, fetal intraperitoneal saline instillation. I n a karyotypically normal fetus with normal somatic growth, demonstration of normal fetal kidneys together with a functioning urinary bladder, in presence of severe oligohydramnios, is very suggestive of the diagnosis. Since pulmonary hypoplasia is the major cause of neonatal mortality in these cases, restoration of normal amniotic fluid volume by serial amnio-infusion was attempted. Although amnio-infusion is an important diagnostic aid in the evaluation of severe midtrimester oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth remains to be evaluated.
Key words: vesico-rectal fistula, prenatal diagnosis, prenatal ultrasound, amnio-infusion, oligohydramnios, pulmonary hypoplasia
Introduction Severe second trimester oligohydramnios is a rare complication of pregnancy. It may or may not be associated with fetal malformations. Irrespective of the .cause of oligohydramnios fetal salvage is very poor.” The common causes are very preterm rupture of membranes, severe intrauterine growth retardation and fetal malformations affecting urine production or excretion. Urorectal septum defects resulting in vesico-rectal fistula is a rare congenital abnormality causing
severe midtrimester oligohydramnios. We report here the prenatal diagnosis of a case of vesico-rectal fistula and the management attempting fetal salvage. Case Report
A 26-year-old subfertile woman conceived following in wityo fertilization and tuba1 embryo transfer. A routine ultrasound scan a t 22 weeks showed severe oligohydramnios. The fetal measurements were below 5th percentile for dates and intra-abdominal con-
Received: Dec. 28, 1991 Reprint request to: Dr. A Biswas, Department of Obstetrics and Gynaecology, National University Hospital, National University of Singapore, Singapore 0511
319
C. A N A N D A W M A R ET AL.
Fig. 1. Antenatal ultrasound picture showing fetal bladder and highly echogenic intestines.
tents appeared highly echogenic (Fig. 1). No other morphologic abnormality was visible. There was no history suggesting premature rupture of membranes. To improve ultrasonographic visualization of fetal intra-abdominal structures 40 ml of warm normal saline was instilled into fetal peritoneal cavity.2) Both kidneys appeared normal and the hyperechoic loops of bowel were thought to be the consequence of meconium peritonitis. However no meconium was seen after aspirating the instilled saline from the peritoneal cavity. Fetal bladder filling was visible during scanning. Fetal blood sampling was carried out by needling the intrahepatic part of the umbilical vein. Analysis of the fetal blood showed a normal karyotype (46XY),normal total IgM (0.09 g/dZ;'normal cord blood range 0.063-0.25 g/dZ), and normal pH and blood gases. Flow velocity waveforms and blood flow indices in umbilical artery and fetal aorta were normal for gestation. On repeat scanning at 23 weeks the oligohydramnios was seen to be persisting, fetal movements were sluggish and breathing movements were not seen. Paradoxically fetal bladder filling and emptying was visible in spite of the continuing severe oligohydramnios. 320
Based on a previous report with similar findings,a) fetal vesico-rectal fistula with anourethral atresia was suspected. On closer scrutiny fetal lower bowel appeared to fill up concurrently with bladder emptying, strengthening the suspicion of vesico-rectal fistula. I n order to prevent the development of pulmonary hypoplasia due to oligohydramnios, amnio-infusion was carried out with 300 ml of warm normal saline under ultrasound guidance as described el~ewhere.~*b) The infusion rate was kept between 15-20 mllmin. Since apparent amniotic fluid pockets are often packed with umbilical cord, colour flow imaging and Doppler facilities were used to aid correct needle placement. The poor prognosis and experimental nature of repeated amnioinfusion was explained to the couple and a written consent was obtained. Following amnio-infusion the amniotic fluid index (AFI)6) and fetal movements improved and breathing movements appeared. However no amniotic fluid pockets were visible on ultrasound scan done a week later. Saline amnioinfusion was repeated at weekly intervals. At each occasion 250-300d of saline was instilled. Although fetal breathing movements were seen after each amnio-infusion, fetal
WICO-RECTAL FISTULA
Fig. 2. Urinary bladder, rectum and colon removed at autopsy showing the vesico-rectal fistula. chest circumference remained smaller than that expected for gestational age and chest/ abdominal circumference ratio was always below the 5th percentile. Blood flow velocity studies were normal for umbilical artery and fetal aorta. Tocolytic drugs or antibiotics were not used following any of the procedures. Fetal growth continued along the 25th percentile. Biweekly cardiotocography showed normal baseline rate and variability. She went into spontaneous labour at 33 weeks. The fetus was presenting by breech. Because of strong suspicion of pulmonary hypoplasia vaginal breech delivery was allowed following extensive discussion with the couple. She delivered a male baby weighing 2,040 g. The Apgar score at 1 min was 6 but worsened to 2 at 5 min. Ventilating the baby was difficultand lung expansion was poor despite high ventilatory pressure, suggesting pulmonary hypoplasia. The baby died 2 hours after birth. Examination of the baby showed a bifid scrotum, absent urethra and an atretic anus. Autopsy revealed a vesico-rectal fistula and dilated colon (Fig. 2). Both lungs were hypoplastic with no evidence of infection. The lungs weighed 28.2 g, which was 1.38% of the body weight. Lung histology was normal
except for a low mean radial alveolar count (4.42).
Discussion Vesico-rectal fistula is a rare congenital defect. It arises from a failure of fusion between the urogenital septum and the cloaca1 membrane during the partitioning of the embryonic cloaca. Anourethral atresia is usually associated. The diagnosis should be considered in cases with severe oligohydramnios detected in midtrimester, especially if fetal bladder filling and emptying is visible without any improvement in amniotic fluid volume. In presence of severe oligohydramnios, ultrasonographic visualization of the fetus is very poor because of a lack of adequate acoustic window. Saline amnio-infusion improves visibility.') The procedure could be technically difficult and use of colour flow imaging could help to avoid inadvertent puncture of cord vessels. Evaluation of the intra-abdominal structures, especially the fetal kidneys, could be further improved by intraperitoneal instillation of a small volume (30 to 50 mZ) of normal saline.2) Fetal kidneys of normal size and echogenecity and a functioning urinary
32l
C.
ANANDAKUMAR BT AL.
bladder could be demonstrated with these procedures but evaluation should also include morphometric measurements and Doppler blood flow studies of fetal and utero-placental circulation to detect growth retardation, and fetal cord blood sampling for karyotyping, total IgM, pH and blood gases. The intra-abdominal echogenic mass was thought to be due to meconium peritonitis. The other possibility in a male fetus was intra-abdominal teratoma, which was ruled out when peristalsis was noted within the mass. However at autopsy there was no evidence of meconium peritonitis. It is probable that the high echogenecity of the bowel wall was caused by meconium lining the bowel wall contrasting with the intraluminal urine, which was also reported in a previous case report8) In cases of severe oligohydramnios, in the absence of lethal malformations, pulmonary hypoplasia is the major cause for perinatal mortality and morbidity.8) The likelihood of lethal pulmonary hypoplasia is directly related to how early in gestation oligohydramnios develops, its severity, duration and etiology.9) Numerous sonographic criteria to predict the occurrence and severity of pulmonary hypoplasia have been suggested. Subnormal chest circumference measurementslo) and low or declining thoraciclabdominal circumference ratio11) have been found to correlate well with subsequent development of pulmonary hypoplasia. The mechanism by which oligohydramnios produces pulmonary hypoplasia is poorly understood. Extrinsic compression, which is responsible for the external features of Potter's syndrome12) is commonly believed to be the cause of lung hypoplasia in cases of severe oligohydramnios. However contrary to expectation intra-amniotic pressure have been found to be low or low normal in these cases.4) It has been postulated that in presence of low intra-amniotic pressure, the alveolar-amniotic pressure gradient is increased-leading to increased loss of lung fluid. Loss of internal stenting due to a reduction in lung liquid volume can impair lung growth.18) Intraamniotic pressure has been shown to improve
322
following amnio-infusion of normal saline.') This, in turn, should halt the chronic loss of lung fluid and improve lung growth. Lung growth would also be promoted by the stimulation of respiratory movements which is usually seen following amnio-infusion. In addition, it has been presumed that improved amniotic fluid volume could prevent the development of deformations secondary to oligohydramnios.l2) Attention was therefore focused towards improving amniotic fluid volume by repeated amnio-infusion.14) In spite of repeated amnio-infusion and at least temporary restoration of amniotic fluid volume fetal chest circumference/abdominal circumference ratio failed to improve, suggesting failure of progressive lung growth. The 250-300 ml saline infused was considered adequate according to known amniotic fluid volume estimations.15) However it would be ideal to measure the intra-amniotic pressure during the procedure, as excessive pressure may lead to amniorrhexis, while inadequate pressure may not have the desired effect on the pulmonary tree.16) Although amnio-infusion is an excellent diagnostic aid in the assessment of severe oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth awaits further evaluation. Development of pulmonary hypoplasia depends on the severity, time of onset and duration of oligohydramnios. By inducing oligohydramnios in a guineapig model, Moessinger et al.17) has demonstrated that the greatest effect is seen when oligohydramnios occurs in the canalicular stage of lung development. In the human fetus the canalicular phase of lung growth spans from 17 to 24 weeks. Thibeault et d.9)observed that pulmonary hypoplasia can result from premature rupture of membranes associated severe oligohydramnios of as short as 6 days duration. Hence, for amnio-infusion to succeed in the prevention of pulmonary hypoplasia, diagnosis before 20 weeks, earlier, more frequent and possibly larger volume amnioinfusion, together with intra-amniotic pressure monitoring,'6) might be required.
WICO-RBCTAL FISTULA
References 1. Barss VA, Benacerraf BR, Frigoletto FD. Second trimester oligohydramnios, a predictor of poor fetal outcome. Obstet Gynecol 1984; 64: 608-610 2. Nicolini U, Santaloya J, Hubinont C, Fisk N, Maxwell D, Rodeck CH. Visualization of fetal intra-abdominal organs in second trimester severe oligohydramnios by intraperitoneal infusion. P r m t Diagn 1989a; 9: 191-194 3. Arulkumaran S, Nicolini U, Fisk NM, Rodeck CH. Fetal vesicorectal fistula causing oligohydramnios in the second trimester. Br J Obstet Gynaecoll990; 97: 449-451 4. Nicolini U, Fisk NM, Rodeck CH, Talbert DG, Wigglesworth JS. Low amniotic pressure in oligohydramnios: Is this the cause of pulmonary hypoplasia? Am J Obstet Gynecol 1989b; 161: 1098-1101 5. Arulkumaran S, Rodeck CH. Invasive prental diagnostic techniques. Fetal Med Rev 1990; 2: 171-185 6. Phelan JP, Ahn MO, Smith CV, Rutherford SE, Anderson E. Amniotic fluid index measurements during pregnancy. J Repord Med 1987; 32: 601-604 7. Gembruch U, Hansmann M. Artificial instillation of amniotic fluid as a new technique for the diagnostic evaluation of cases of oligohydramnios. Prenat DMgn 1988; 8: 33-45 8. Tibboel D, Gailard JL, Spritzer R, Wallenberg HC. Pulmonary hypoplasia secondary to oligohydramnios with very premature rupture of fetal membranes. Eur J Pediatr 1990; 149: 496499 9. Thibeault DW, Beatty EC, Hall RC, Bowen SK, O’Neil DH. Neonatal. pulmonary hypoplasia with premature rupture of the fetal
10.
11.
12.
13.
14.
15.
16.
17.
membranes and oligohydramnios. J Pediatr 1985;107:273-278 Nimrod C, Davies D, Iwanicki S, Harder J, Persaud D, Nicholson S. Ultrasound prediction of pulmonary hypoplasia. Obstet Gynecol 1986;68:495-498 Johnson A, Callan NA, Bhutani VK, Colmorgen GHC, Weiner S, Bolognese RJ. Ultrasonic ratio of fetal thoracic to abdominal circumference: An association with fetal pulmonary hypoplasia. Am J Obstet Gynecoll987; 157: 764769 Thomas IT, Smith DW. Oligohydramnios, cause of the nonrenal features of Potter’s syndrome, including pulmonary hypoplasia. J Pediatr 1974; 84: 811-814 Adzick NS, Harrison MR, Glick PL, Villa RL, Finkbeiner W. Experimental pulmonary hypoplasia and oligohydramnios: Relative contributions of lung fluid and fetal breathing movements. J Pediatr Surg 1984; 19: 658-665 Fisk NM, Ronderos-Dumit D, Soliani A, Nicolini U, Vaughan J, Rodeck CH. Diagnostic and therapeutic transabdominal amnioinfusion in oligohydramnios. Obstet Gynecol 1991 ;78: 270-278 Gadd RL. The volume of liquor amnii in normal and abnormal pregnancies. J Obstet Oynaecol Brit Cwlth 1966; 73: 11-22 Fisk NM, Tannirandorn Y,Nicolini U, Talbert DG, Rodeck CH. Amniotic pressure in disorder of amniotic fluid volume. Obstet Oynecol 1990; 76: 210-214 Moessinger AC, Collins MH, Blanc WA, Rey HA, Stanley James L. Oligohydramnios induced lung hypoplasia: The influence of timing and duration in gestation. Pediatr Res 1986; 20: 951-954
323
A Case Report : Vesico-Rectal Fistula with Ano-Urethral Atresia
C. Anandakumar, Y. C. Wong, A. Biswas, A. Venkat, D. Chia, S. Arulkumaran, and S. S. Ratnam Division of Feto-Maternal Medicine, Department of Obstetrics and Oynaecology, National University Hospital, Singapore
Abstract Vesico-rectal fistula is a rare congenital abnormality causing severe early second trimester oligohydramnios. Prenatal diagnosis of such a case is reported here. Ultrasound diagnosis could be aided by transabdominal amnio-infusion and, if necessary, fetal intraperitoneal saline instillation. I n a karyotypically normal fetus with normal somatic growth, demonstration of normal fetal kidneys together with a functioning urinary bladder, in presence of severe oligohydramnios, is very suggestive of the diagnosis. Since pulmonary hypoplasia is the major cause of neonatal mortality in these cases, restoration of normal amniotic fluid volume by serial amnio-infusion was attempted. Although amnio-infusion is an important diagnostic aid in the evaluation of severe midtrimester oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth remains to be evaluated.
Key words: vesico-rectal fistula, prenatal diagnosis, prenatal ultrasound, amnio-infusion, oligohydramnios, pulmonary hypoplasia
Introduction Severe second trimester oligohydramnios is a rare complication of pregnancy. It may or may not be associated with fetal malformations. Irrespective of the .cause of oligohydramnios fetal salvage is very poor.” The common causes are very preterm rupture of membranes, severe intrauterine growth retardation and fetal malformations affecting urine production or excretion. Urorectal septum defects resulting in vesico-rectal fistula is a rare congenital abnormality causing
severe midtrimester oligohydramnios. We report here the prenatal diagnosis of a case of vesico-rectal fistula and the management attempting fetal salvage. Case Report
A 26-year-old subfertile woman conceived following in wityo fertilization and tuba1 embryo transfer. A routine ultrasound scan a t 22 weeks showed severe oligohydramnios. The fetal measurements were below 5th percentile for dates and intra-abdominal con-
Received: Dec. 28, 1991 Reprint request to: Dr. A Biswas, Department of Obstetrics and Gynaecology, National University Hospital, National University of Singapore, Singapore 0511
319
C. A N A N D A W M A R ET AL.
Fig. 1. Antenatal ultrasound picture showing fetal bladder and highly echogenic intestines.
tents appeared highly echogenic (Fig. 1). No other morphologic abnormality was visible. There was no history suggesting premature rupture of membranes. To improve ultrasonographic visualization of fetal intra-abdominal structures 40 ml of warm normal saline was instilled into fetal peritoneal cavity.2) Both kidneys appeared normal and the hyperechoic loops of bowel were thought to be the consequence of meconium peritonitis. However no meconium was seen after aspirating the instilled saline from the peritoneal cavity. Fetal bladder filling was visible during scanning. Fetal blood sampling was carried out by needling the intrahepatic part of the umbilical vein. Analysis of the fetal blood showed a normal karyotype (46XY),normal total IgM (0.09 g/dZ;'normal cord blood range 0.063-0.25 g/dZ), and normal pH and blood gases. Flow velocity waveforms and blood flow indices in umbilical artery and fetal aorta were normal for gestation. On repeat scanning at 23 weeks the oligohydramnios was seen to be persisting, fetal movements were sluggish and breathing movements were not seen. Paradoxically fetal bladder filling and emptying was visible in spite of the continuing severe oligohydramnios. 320
Based on a previous report with similar findings,a) fetal vesico-rectal fistula with anourethral atresia was suspected. On closer scrutiny fetal lower bowel appeared to fill up concurrently with bladder emptying, strengthening the suspicion of vesico-rectal fistula. I n order to prevent the development of pulmonary hypoplasia due to oligohydramnios, amnio-infusion was carried out with 300 ml of warm normal saline under ultrasound guidance as described el~ewhere.~*b) The infusion rate was kept between 15-20 mllmin. Since apparent amniotic fluid pockets are often packed with umbilical cord, colour flow imaging and Doppler facilities were used to aid correct needle placement. The poor prognosis and experimental nature of repeated amnioinfusion was explained to the couple and a written consent was obtained. Following amnio-infusion the amniotic fluid index (AFI)6) and fetal movements improved and breathing movements appeared. However no amniotic fluid pockets were visible on ultrasound scan done a week later. Saline amnioinfusion was repeated at weekly intervals. At each occasion 250-300d of saline was instilled. Although fetal breathing movements were seen after each amnio-infusion, fetal
WICO-RECTAL FISTULA
Fig. 2. Urinary bladder, rectum and colon removed at autopsy showing the vesico-rectal fistula. chest circumference remained smaller than that expected for gestational age and chest/ abdominal circumference ratio was always below the 5th percentile. Blood flow velocity studies were normal for umbilical artery and fetal aorta. Tocolytic drugs or antibiotics were not used following any of the procedures. Fetal growth continued along the 25th percentile. Biweekly cardiotocography showed normal baseline rate and variability. She went into spontaneous labour at 33 weeks. The fetus was presenting by breech. Because of strong suspicion of pulmonary hypoplasia vaginal breech delivery was allowed following extensive discussion with the couple. She delivered a male baby weighing 2,040 g. The Apgar score at 1 min was 6 but worsened to 2 at 5 min. Ventilating the baby was difficultand lung expansion was poor despite high ventilatory pressure, suggesting pulmonary hypoplasia. The baby died 2 hours after birth. Examination of the baby showed a bifid scrotum, absent urethra and an atretic anus. Autopsy revealed a vesico-rectal fistula and dilated colon (Fig. 2). Both lungs were hypoplastic with no evidence of infection. The lungs weighed 28.2 g, which was 1.38% of the body weight. Lung histology was normal
except for a low mean radial alveolar count (4.42).
Discussion Vesico-rectal fistula is a rare congenital defect. It arises from a failure of fusion between the urogenital septum and the cloaca1 membrane during the partitioning of the embryonic cloaca. Anourethral atresia is usually associated. The diagnosis should be considered in cases with severe oligohydramnios detected in midtrimester, especially if fetal bladder filling and emptying is visible without any improvement in amniotic fluid volume. In presence of severe oligohydramnios, ultrasonographic visualization of the fetus is very poor because of a lack of adequate acoustic window. Saline amnio-infusion improves visibility.') The procedure could be technically difficult and use of colour flow imaging could help to avoid inadvertent puncture of cord vessels. Evaluation of the intra-abdominal structures, especially the fetal kidneys, could be further improved by intraperitoneal instillation of a small volume (30 to 50 mZ) of normal saline.2) Fetal kidneys of normal size and echogenecity and a functioning urinary
32l
C.
ANANDAKUMAR BT AL.
bladder could be demonstrated with these procedures but evaluation should also include morphometric measurements and Doppler blood flow studies of fetal and utero-placental circulation to detect growth retardation, and fetal cord blood sampling for karyotyping, total IgM, pH and blood gases. The intra-abdominal echogenic mass was thought to be due to meconium peritonitis. The other possibility in a male fetus was intra-abdominal teratoma, which was ruled out when peristalsis was noted within the mass. However at autopsy there was no evidence of meconium peritonitis. It is probable that the high echogenecity of the bowel wall was caused by meconium lining the bowel wall contrasting with the intraluminal urine, which was also reported in a previous case report8) In cases of severe oligohydramnios, in the absence of lethal malformations, pulmonary hypoplasia is the major cause for perinatal mortality and morbidity.8) The likelihood of lethal pulmonary hypoplasia is directly related to how early in gestation oligohydramnios develops, its severity, duration and etiology.9) Numerous sonographic criteria to predict the occurrence and severity of pulmonary hypoplasia have been suggested. Subnormal chest circumference measurementslo) and low or declining thoraciclabdominal circumference ratio11) have been found to correlate well with subsequent development of pulmonary hypoplasia. The mechanism by which oligohydramnios produces pulmonary hypoplasia is poorly understood. Extrinsic compression, which is responsible for the external features of Potter's syndrome12) is commonly believed to be the cause of lung hypoplasia in cases of severe oligohydramnios. However contrary to expectation intra-amniotic pressure have been found to be low or low normal in these cases.4) It has been postulated that in presence of low intra-amniotic pressure, the alveolar-amniotic pressure gradient is increased-leading to increased loss of lung fluid. Loss of internal stenting due to a reduction in lung liquid volume can impair lung growth.18) Intraamniotic pressure has been shown to improve
322
following amnio-infusion of normal saline.') This, in turn, should halt the chronic loss of lung fluid and improve lung growth. Lung growth would also be promoted by the stimulation of respiratory movements which is usually seen following amnio-infusion. In addition, it has been presumed that improved amniotic fluid volume could prevent the development of deformations secondary to oligohydramnios.l2) Attention was therefore focused towards improving amniotic fluid volume by repeated amnio-infusion.14) In spite of repeated amnio-infusion and at least temporary restoration of amniotic fluid volume fetal chest circumference/abdominal circumference ratio failed to improve, suggesting failure of progressive lung growth. The 250-300 ml saline infused was considered adequate according to known amniotic fluid volume estimations.15) However it would be ideal to measure the intra-amniotic pressure during the procedure, as excessive pressure may lead to amniorrhexis, while inadequate pressure may not have the desired effect on the pulmonary tree.16) Although amnio-infusion is an excellent diagnostic aid in the assessment of severe oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth awaits further evaluation. Development of pulmonary hypoplasia depends on the severity, time of onset and duration of oligohydramnios. By inducing oligohydramnios in a guineapig model, Moessinger et al.17) has demonstrated that the greatest effect is seen when oligohydramnios occurs in the canalicular stage of lung development. In the human fetus the canalicular phase of lung growth spans from 17 to 24 weeks. Thibeault et d.9)observed that pulmonary hypoplasia can result from premature rupture of membranes associated severe oligohydramnios of as short as 6 days duration. Hence, for amnio-infusion to succeed in the prevention of pulmonary hypoplasia, diagnosis before 20 weeks, earlier, more frequent and possibly larger volume amnioinfusion, together with intra-amniotic pressure monitoring,'6) might be required.
WICO-RBCTAL FISTULA
References 1. Barss VA, Benacerraf BR, Frigoletto FD. Second trimester oligohydramnios, a predictor of poor fetal outcome. Obstet Gynecol 1984; 64: 608-610 2. Nicolini U, Santaloya J, Hubinont C, Fisk N, Maxwell D, Rodeck CH. Visualization of fetal intra-abdominal organs in second trimester severe oligohydramnios by intraperitoneal infusion. P r m t Diagn 1989a; 9: 191-194 3. Arulkumaran S, Nicolini U, Fisk NM, Rodeck CH. Fetal vesicorectal fistula causing oligohydramnios in the second trimester. Br J Obstet Gynaecoll990; 97: 449-451 4. Nicolini U, Fisk NM, Rodeck CH, Talbert DG, Wigglesworth JS. Low amniotic pressure in oligohydramnios: Is this the cause of pulmonary hypoplasia? Am J Obstet Gynecol 1989b; 161: 1098-1101 5. Arulkumaran S, Rodeck CH. Invasive prental diagnostic techniques. Fetal Med Rev 1990; 2: 171-185 6. Phelan JP, Ahn MO, Smith CV, Rutherford SE, Anderson E. Amniotic fluid index measurements during pregnancy. J Repord Med 1987; 32: 601-604 7. Gembruch U, Hansmann M. Artificial instillation of amniotic fluid as a new technique for the diagnostic evaluation of cases of oligohydramnios. Prenat DMgn 1988; 8: 33-45 8. Tibboel D, Gailard JL, Spritzer R, Wallenberg HC. Pulmonary hypoplasia secondary to oligohydramnios with very premature rupture of fetal membranes. Eur J Pediatr 1990; 149: 496499 9. Thibeault DW, Beatty EC, Hall RC, Bowen SK, O’Neil DH. Neonatal. pulmonary hypoplasia with premature rupture of the fetal
10.
11.
12.
13.
14.
15.
16.
17.
membranes and oligohydramnios. J Pediatr 1985;107:273-278 Nimrod C, Davies D, Iwanicki S, Harder J, Persaud D, Nicholson S. Ultrasound prediction of pulmonary hypoplasia. Obstet Gynecol 1986;68:495-498 Johnson A, Callan NA, Bhutani VK, Colmorgen GHC, Weiner S, Bolognese RJ. Ultrasonic ratio of fetal thoracic to abdominal circumference: An association with fetal pulmonary hypoplasia. Am J Obstet Gynecoll987; 157: 764769 Thomas IT, Smith DW. Oligohydramnios, cause of the nonrenal features of Potter’s syndrome, including pulmonary hypoplasia. J Pediatr 1974; 84: 811-814 Adzick NS, Harrison MR, Glick PL, Villa RL, Finkbeiner W. Experimental pulmonary hypoplasia and oligohydramnios: Relative contributions of lung fluid and fetal breathing movements. J Pediatr Surg 1984; 19: 658-665 Fisk NM, Ronderos-Dumit D, Soliani A, Nicolini U, Vaughan J, Rodeck CH. Diagnostic and therapeutic transabdominal amnioinfusion in oligohydramnios. Obstet Gynecol 1991 ;78: 270-278 Gadd RL. The volume of liquor amnii in normal and abnormal pregnancies. J Obstet Oynaecol Brit Cwlth 1966; 73: 11-22 Fisk NM, Tannirandorn Y,Nicolini U, Talbert DG, Rodeck CH. Amniotic pressure in disorder of amniotic fluid volume. Obstet Oynecol 1990; 76: 210-214 Moessinger AC, Collins MH, Blanc WA, Rey HA, Stanley James L. Oligohydramnios induced lung hypoplasia: The influence of timing and duration in gestation. Pediatr Res 1986; 20: 951-954
323
