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Prophylactic amnioinfusion as a treatment for oligohydramnios in laboring patients: A prospective, randomized trial
Prophylactic amnioinfusion as a treatment for oligohydramnios in laboring patients: A prospective, randomized trial David B. Schrimmer, MD, Charles J. Macri, MD, and Richard H. Paul, MD Los Angeles, California Prophylactic amnioinfusion was studied in a randomized sample of 305 patients with oligohydramnios in labor. One hundred seventy-five patients underwent amnioinfusion with the remainder serving as controls. Amniotic fluid was titrated to an amniotic fluid index >10.0 cm in the treatment group. Patients receiving amnioinfusion had significantly less operative intervention for fetal distress (p = 0.0001) and fewer cesarean sections (p = 0.0001). Umbilical artery pH at the time of delivery also was increased (p = 0.0001). Rates of amnionitis and endometritis were not significantly different between infused patients and controls, although the length of hospital stay was significantly decreased (p = 0.002) in the treatment group. Our data support earlier reports in the literature that amnioinfusion is a useful technique for decreasing intrapartum morbidity for both mother and fetus. (AM J OBSTET GVNECOL 1991 ;165:972-5.)
Key words: Amnioinfusion, amniotic fluid index, operative intervention, fetal distress Amnioinfusion is being used for several indications, including prophylactic treatment of oligohydramnios, elimination of significant variable decelerations in labor, j., and· the prevention of meconium aspiration in laboring patients with thick meconium" Initial studies in the literature have been promising, with decreased operative intervention for fetal distress and improved neonatal outcome reported. 5 These findings are believed to be due to the restored cushioning effect of amniotic fluid and the subsequent prevention of cord compression. These initial studies, however, have raised questions about the use of amnioinfusion in statistically reducing the incidence of cesarean section for fetal distress and the relationship between amnioinfusion and intrapartum or postpartum infection. 5 , 6 The purpose of this study was to examine the effect of prophylactic amnioinfusion on the incidence of operative intervention for fetal distress, the fetal outcome, and its effect on the incidence of intrapartum and postpartum infection.
Material and methods Between Aug. 1, 1989, and Sept. 15, 1990, 305 patients at Los Angeles County/University of Southern California Women's Hospital were studied in a prospective, randomized fashion. Patients were initially identified as having oligohydramnios on admission on the basis of a four-quadrant amniotic fluid index of <5.0 cm at the time of admission. 7 Patients either were From the Department of Obstetrics and Gynecology, Women's Hospital, University of Southern California, School of Medicine. Presented at the Eleventh Annual Meeting of the Society of Perinatal Obstetricians, San Francisco, California, January 28-February 2, 1991, Reprint requests: David B, Schrimmer, MD, Sharp Perinatal Center, 8010 Frost St" San Diego, CA 92123,
6/6/30914
in labor or were being admitted for induction of labor because of oligohydramnios. Membranes could be either intact or spontaneously ruptured on admission. Criteria for enrollment also included a singleton gestation, vertex presentation, and normal fetal heart rate baseline and variability. Exclusion criteria included moderate or severe variable decelerations, late decelerations, vaginal bleeding, fetal anomalies, and chorioamnionitis. Patients were not excluded because of the presence or absence of meconium. Once enrolled, patients were not excluded from the study, nor were they randomized to any other studies. Eligible patients who agreed to participate in the institutional review board-approved study were enrolled after providing written informed consent. After enrollment, patients were prospectively randomized to a treatment group (amnioinfusion) or a nontreatment group. Randomization was done by computer randomization and sequentially numbered opaque, sealed envelopes. The ratio of treatment to nontreatment groups was 3: 2. The 3: 2 ratio was chosen to encourage enrollment. Study design included power calculations that were based on an a error of 0.05 to establish statistical significance and a 13 error of 0.20, Calculations showed that a minimum of 114 patients were required in each arm, on the basis of the differential rate of cesarean delivery because of fetal distress (13% vs 3%) and the difference in the incidence of amnionitis (20% vs 7%) as reported by Strong et aJ.5 in an earlier study completed at our institution. 5 After adequate cervical dilation had been achieved, patients had an intrauterine pressure catheter inserted, through which those patients in the amnioinfusion group received an infusion of 500 ml normal saline solution at 37° C. Saline solution was infused by gravity
Amnioinfusion for therapy of oligohydramnios in labor 973
Volume 165 Number 4, Part I
Table I. Patient characteristics Infusion gorup (N = 175)
Control group
23.3 ± 3.9 1.7 ± 0.7 0.5 ± 0.6 104 (59.4 %) 71 (40.6%) 290 ± 7.7
23.0 ± 4.3 1.7 ± 0.8 0.4 ± 0.7 88 (67.7%) 42 (32.3%) 291 ± 8.1
NS NS NS NS NS NS
2.9 ± 1.0
3.1 ± 0.9
NS
3.6 ± 0.7
3.4 ± 0.8
NS
Infusion group
Control group
p Value
Normal spontaneous vaginal delivery Forceps Vacuum Cesarean
1221175 (69.7 %)
661130 (50.8 %)
0.001
17/175 (9.7 %)
111175 (6.3 %) 251175 (14.3 %)
171130 (13.0 %) 111130 (8.5%) 361130 (27.7%)
NS NS
0.006
Total operative deliveries
531175 (30.3 %)
641130 (49.2%)
0.001
Age (yr) Gravidity Parity Nulliparous women Multiparous women Gestational age (days) Initial cervical dilatation (cm) Amniotic fluid index on admission
(N
= 130)
P Value
NS, Not significant.
Table II. Method of delivery
NS, Not significant.
flow over 20 to 30 minutes (15 to 25 mIlmin). After the initial infusion, ultrasonography was performed to measure the amniotic fluid index and confirm adequate restoration of intrauterine fluid volume (amniotic fluid index, 2!: 10.0 cm). If the amniotic fluid index was found to be 2!: 10.0 cm, no further fluid was added. If the amniotic fluid index was :::=5.0 cm and <10.0 cm, an additional 250 ml was given, and if the amniotic fluid index was <5.0 cm, 500 ml was again given after intrauterine catheter placement was checked. Ultrasonography was repeated hourly, with the above-noted schedule followed to maintain an amniotic fluid index of 2!: lO.O cm. Patients were allowed to labor, and on delivery cord gas values were obtained. Infants and parturients were monitored for signs of infection or other complications until discharge from the hospital. It should be noted that the study was not blinded, because of the need for hourly ultrasonographic examinations and reinfusion in some patients. In an effort to eliminate bias, managing physicians were not the clinical investigators. After completion of the study, data from all patients were included and reviewed. Tests for statistical comparison included the X· , Mann-Whitney U, and Student t lest.
Results After enrollment and randomization, 305 patients were studied. One hundred seventy-five patients un-
derwent amnioinfusion, and 130 patients served as a control group. Comparison of the treatment group versus the control group revealed no statistical differences between the groups with regard to age, parity, gestational age, initial cervical examination or admission amniotic fluid index (Table I). In the infusion group patients received an average of 1.2 ± 0.5 infusions and an average volume of 554 ml (± 122 ml). Average increase in amniotic fluid index with the initial 500 ml infusion was 8.4 ± 1.4 cm. Twenty-three patients required more than one infusion, while 152 needed just the initial 500 ml bolus. In those requiring a second infusion, the average time to that infusion was 4.6 ± 1.6 hours. There were no infusion failures, although the intrauterine pressure catheter had to be replaced in three patients. No infusions had to be stopped because of fetal distress. Comparison of the delivery methods between the infusi on group and the control group shows significant differences in the overall incidence of cesarean section, total operative deliveries, operative deliveries for fetal distress, and cesarean section for fetal distress (Tables II and III). Neonatal outcome revealed a significant difference in cord pH between the two groups, although 5-minute Apgar scores were not significantly affected (Table IV). Amnioinfusion did not appear to h ave any adverse effect on the fetus. None had seizures in the newborn period after the amnioinfusion, and there were no
974
October 1991 Am J Obstet Gynecol
Schrimmer, Macri, and Paul
Table III. Operative intervention because of fetal distress Forceps Vacuum Cesarean TOTAL
No distress
Infusion group
Control group
p Value
41175 (2.3%) 31175 (1.7%) 71175 (4.0%)
5/130 (3.8%) 41130 (3.1%) 251130 (19.2%)
NS NS 0.0001
141175 (8.0%)
34/130 (26.2%)
0.0001
1611175 (92.0%)
96/130 (73.8%)
0.0001
NS, Not significant.
Table IV. Neonatal outcome Birth weight (gm) Umbilical artery cord pH No. with pH <7.20 Apgar scores <7 1 min 5 min
Infusion group
Control group
p Value
3545 ± 350 7.27 ± 0.05
3459 ± 325 7.23 ± 0.09
NS 0.0001*
141175 (8.0%)
39/130 (30.0%)
0.0001
141175 (8.0%) 61175 (3.4%)
451130 (34.6%) 9/130 (6.9%)
0.0001 NS
Infusion group
Control group
p Value
181175 (10.3%) 71175 (4.0%) 2.5 ± l.l
9/130 (6.9%) 101130 (7.7%) 3.0 ± 1.5
NS NS <0.01*
23/175 (13.5%) 2.5 ± l.l
37/130 (29.5%) 3.9 ± 3.8
0.002 <0.001*
241175 (13.7%)
451130 (33.2%)
0.0001
NS, Not significant. *Student t test.
Table V. Infection Amnionitis Endometritis Length of hospital stay (maternal, days) No. with stay >3 d:!ys Length of hospital stay (infant, days)t No. with stay >3 days NS, Not significant. *Mann-Whitney U. tRefiects maternal stay.
other newborn problems associated with the procedure. The incidence of both amnionitis and endometritis was not significantly different between the infusion and the control group. Interestingly, the length of hospital stay was significantly longer in the control group, a reflection of the increased rate of operative deliveries observed in this group (Table V). Comment
The role of amniotic fluid in providing a cushion for the fetal umbilical cord has now been suggested by several authors. 5 • 8 The results obtained in our study provide further evidence that the maintenance of adequate amniotic fluid volume is important during the intrapartum period. The apparent protection against cord compression seems to have a direct effect on both maternal and fetal outcome, and our results lend strong
support to the technique of amnioinfusion as a prophylactic treatment for oligohydramnios in labor. In a comparison of the methods of delivery (Tables II and III), it is readily apparent that the infusion group has a statistically significant increase in spontaneous vaginal deliveries and a subsequent decrease in operative deliveries. Operative intervention specifically because of fetal distress is also significantly reduced when one examines the overall rate (including forceps and vacuum) and when cesarean section alone is examined. Prior studies of cesarean section rates have suggested this trend but have not shown a statistical difference because of their smaller sample sizes. 2 • 5 This finding clearly translates to decreased maternal morbidity and a reduction in the number of cesarean deliveries. Of interest is the observation that operative vaginal deliveries because of fetal distress are higher in the study
Volume 165 Number 4, Part 1
population (both infused and noninfused patients) than in the general population at Women's HospitaL This is believed to reflect the complication of oligohydramnios in the study population. The observation that the rate did not return to normal in the infusion group suggests that in some patients oligohydramnios is a symptom of a larger problem, not simply corrected by amnioinfusion and restoration of a normal amniotic fluid index. With regard to fetal outcome, our data show a significant improvement in umbilical artery cord pH in the amnioinfused group. One-minute Apgar scores also were improved, but the 5-minute scores were not statistically different. Our results are similar to those reported in prior studies 2 . 5 and presumably reflect decreased stress in association with the elimination of repetitive variable decelerations. Of concern in our institution was the possible implication of amnioinfusion with increased rates of amnionitis and endometritis. Strong et aU reported a 13% increase in infection in his preliminary study of infused patients. This enlarged study failed to show a statistical difference between the infection rates between the control and treatment group, and the differences noted were only 3%. Recent work published by Owen et aU has suggested that amnioinfusion may actually provide a protective effect against maternal infection. Our work was unable to confirm this finding. Of great interest was the shortened length of hospital stay in the amnioinfusion group. While this finding is tied to the decreased rate of operative intervention for fetal distress, its importance is nonetheless diminished. In this era of rising medical costs, decreased hospital
Amnioinfusion for therapy of oligohydramnios in labor 975
time for both mother and infant would seem to provide further incentive for using this technique. In summary, this study shows that prophylactic amnioinfusion is a safe and simple technique that may be used for the treatment of oligohydramnios in patients in labor. Its benefits include a decrease in the rate of operative intervention for fetal distress, reduced rates of cesarean section, and decreased length of hospital stay. Amnioinfusion has no apparent adverse effects on the fetus or mother and does not appear to increase the rates of maternal infection. REFERENCES 1. Miyazaki FS, Taylor NA. Saline amnioinfusion for relief of variable or prolonged decelerations. AM] OBSTET GYNECOL 1983; 146:670-8. 2. Nageotte MP, Freeman RK, Garite T], Dorchester W. Prophylactic intrapartum amnioinfusion in patients with preterm premature rupture of membranes. AM] OBSTET GvNECOL 1985;153:557-62. 3. Miyazaki FS, Neverez F. Saline amnioinfusion for relief of repetitive variable decelerations: a prospective randomized study. AM] OBSTET GYNECOL 1985; 153:301-6. 4. Wenstrom KD, Parsons MT. The prevention of meconium aspiration in labor using amnioinfusion. Obstet Gynecol 1989;73:647-51. 5. Strong TH, Hetzler G, Sarno AP, Paul RH. Prophylactic intrapartum amnioinfusion: a randomized clinical trial. AM ] OBSTET GYNECOL 1990;162:1370-5. 6. Owen], Henson BV, Hauth]C. A prospective randomized study of saline solution amnioinfusion. AM] OBSTET GvNECOL 1990;162:1146-9. 7. Phelan]P, Ahn MO, Smith CV, Rutherford SE, Anderson E. Amniotic fluid index measurements during pregnancy. ] Reprod Med 1987;32:601-4. 8. Hon EH. Observations on "pathologic" fetal bradycardia. AM] OBSTET GYNECOL 1959;77: 1084-93.
Bound volumes available to subscribers Bound volumes of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY are available to subscribers (only) for the 1991 issues from the Publisher, at a cost of $61.00 for domestic, $88.27 for Canada, and $84.00 for international for VoL 164 (January-June) and VoL 165 (July-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the JOURNAL name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Mosby- Year Book, Inc., Subscription Services, 11830 Westline Industrial Drive, St. Louis, MO 63146-3318, USA; phone (800) 325-4177, ext. 4351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.
Key words: Amnioinfusion, amniotic fluid index, operative intervention, fetal distress Amnioinfusion is being used for several indications, including prophylactic treatment of oligohydramnios, elimination of significant variable decelerations in labor, j., and· the prevention of meconium aspiration in laboring patients with thick meconium" Initial studies in the literature have been promising, with decreased operative intervention for fetal distress and improved neonatal outcome reported. 5 These findings are believed to be due to the restored cushioning effect of amniotic fluid and the subsequent prevention of cord compression. These initial studies, however, have raised questions about the use of amnioinfusion in statistically reducing the incidence of cesarean section for fetal distress and the relationship between amnioinfusion and intrapartum or postpartum infection. 5 , 6 The purpose of this study was to examine the effect of prophylactic amnioinfusion on the incidence of operative intervention for fetal distress, the fetal outcome, and its effect on the incidence of intrapartum and postpartum infection.
Material and methods Between Aug. 1, 1989, and Sept. 15, 1990, 305 patients at Los Angeles County/University of Southern California Women's Hospital were studied in a prospective, randomized fashion. Patients were initially identified as having oligohydramnios on admission on the basis of a four-quadrant amniotic fluid index of <5.0 cm at the time of admission. 7 Patients either were From the Department of Obstetrics and Gynecology, Women's Hospital, University of Southern California, School of Medicine. Presented at the Eleventh Annual Meeting of the Society of Perinatal Obstetricians, San Francisco, California, January 28-February 2, 1991, Reprint requests: David B, Schrimmer, MD, Sharp Perinatal Center, 8010 Frost St" San Diego, CA 92123,
6/6/30914
in labor or were being admitted for induction of labor because of oligohydramnios. Membranes could be either intact or spontaneously ruptured on admission. Criteria for enrollment also included a singleton gestation, vertex presentation, and normal fetal heart rate baseline and variability. Exclusion criteria included moderate or severe variable decelerations, late decelerations, vaginal bleeding, fetal anomalies, and chorioamnionitis. Patients were not excluded because of the presence or absence of meconium. Once enrolled, patients were not excluded from the study, nor were they randomized to any other studies. Eligible patients who agreed to participate in the institutional review board-approved study were enrolled after providing written informed consent. After enrollment, patients were prospectively randomized to a treatment group (amnioinfusion) or a nontreatment group. Randomization was done by computer randomization and sequentially numbered opaque, sealed envelopes. The ratio of treatment to nontreatment groups was 3: 2. The 3: 2 ratio was chosen to encourage enrollment. Study design included power calculations that were based on an a error of 0.05 to establish statistical significance and a 13 error of 0.20, Calculations showed that a minimum of 114 patients were required in each arm, on the basis of the differential rate of cesarean delivery because of fetal distress (13% vs 3%) and the difference in the incidence of amnionitis (20% vs 7%) as reported by Strong et aJ.5 in an earlier study completed at our institution. 5 After adequate cervical dilation had been achieved, patients had an intrauterine pressure catheter inserted, through which those patients in the amnioinfusion group received an infusion of 500 ml normal saline solution at 37° C. Saline solution was infused by gravity
Amnioinfusion for therapy of oligohydramnios in labor 973
Volume 165 Number 4, Part I
Table I. Patient characteristics Infusion gorup (N = 175)
Control group
23.3 ± 3.9 1.7 ± 0.7 0.5 ± 0.6 104 (59.4 %) 71 (40.6%) 290 ± 7.7
23.0 ± 4.3 1.7 ± 0.8 0.4 ± 0.7 88 (67.7%) 42 (32.3%) 291 ± 8.1
NS NS NS NS NS NS
2.9 ± 1.0
3.1 ± 0.9
NS
3.6 ± 0.7
3.4 ± 0.8
NS
Infusion group
Control group
p Value
Normal spontaneous vaginal delivery Forceps Vacuum Cesarean
1221175 (69.7 %)
661130 (50.8 %)
0.001
17/175 (9.7 %)
111175 (6.3 %) 251175 (14.3 %)
171130 (13.0 %) 111130 (8.5%) 361130 (27.7%)
NS NS
0.006
Total operative deliveries
531175 (30.3 %)
641130 (49.2%)
0.001
Age (yr) Gravidity Parity Nulliparous women Multiparous women Gestational age (days) Initial cervical dilatation (cm) Amniotic fluid index on admission
(N
= 130)
P Value
NS, Not significant.
Table II. Method of delivery
NS, Not significant.
flow over 20 to 30 minutes (15 to 25 mIlmin). After the initial infusion, ultrasonography was performed to measure the amniotic fluid index and confirm adequate restoration of intrauterine fluid volume (amniotic fluid index, 2!: 10.0 cm). If the amniotic fluid index was found to be 2!: 10.0 cm, no further fluid was added. If the amniotic fluid index was :::=5.0 cm and <10.0 cm, an additional 250 ml was given, and if the amniotic fluid index was <5.0 cm, 500 ml was again given after intrauterine catheter placement was checked. Ultrasonography was repeated hourly, with the above-noted schedule followed to maintain an amniotic fluid index of 2!: lO.O cm. Patients were allowed to labor, and on delivery cord gas values were obtained. Infants and parturients were monitored for signs of infection or other complications until discharge from the hospital. It should be noted that the study was not blinded, because of the need for hourly ultrasonographic examinations and reinfusion in some patients. In an effort to eliminate bias, managing physicians were not the clinical investigators. After completion of the study, data from all patients were included and reviewed. Tests for statistical comparison included the X· , Mann-Whitney U, and Student t lest.
Results After enrollment and randomization, 305 patients were studied. One hundred seventy-five patients un-
derwent amnioinfusion, and 130 patients served as a control group. Comparison of the treatment group versus the control group revealed no statistical differences between the groups with regard to age, parity, gestational age, initial cervical examination or admission amniotic fluid index (Table I). In the infusion group patients received an average of 1.2 ± 0.5 infusions and an average volume of 554 ml (± 122 ml). Average increase in amniotic fluid index with the initial 500 ml infusion was 8.4 ± 1.4 cm. Twenty-three patients required more than one infusion, while 152 needed just the initial 500 ml bolus. In those requiring a second infusion, the average time to that infusion was 4.6 ± 1.6 hours. There were no infusion failures, although the intrauterine pressure catheter had to be replaced in three patients. No infusions had to be stopped because of fetal distress. Comparison of the delivery methods between the infusi on group and the control group shows significant differences in the overall incidence of cesarean section, total operative deliveries, operative deliveries for fetal distress, and cesarean section for fetal distress (Tables II and III). Neonatal outcome revealed a significant difference in cord pH between the two groups, although 5-minute Apgar scores were not significantly affected (Table IV). Amnioinfusion did not appear to h ave any adverse effect on the fetus. None had seizures in the newborn period after the amnioinfusion, and there were no
974
October 1991 Am J Obstet Gynecol
Schrimmer, Macri, and Paul
Table III. Operative intervention because of fetal distress Forceps Vacuum Cesarean TOTAL
No distress
Infusion group
Control group
p Value
41175 (2.3%) 31175 (1.7%) 71175 (4.0%)
5/130 (3.8%) 41130 (3.1%) 251130 (19.2%)
NS NS 0.0001
141175 (8.0%)
34/130 (26.2%)
0.0001
1611175 (92.0%)
96/130 (73.8%)
0.0001
NS, Not significant.
Table IV. Neonatal outcome Birth weight (gm) Umbilical artery cord pH No. with pH <7.20 Apgar scores <7 1 min 5 min
Infusion group
Control group
p Value
3545 ± 350 7.27 ± 0.05
3459 ± 325 7.23 ± 0.09
NS 0.0001*
141175 (8.0%)
39/130 (30.0%)
0.0001
141175 (8.0%) 61175 (3.4%)
451130 (34.6%) 9/130 (6.9%)
0.0001 NS
Infusion group
Control group
p Value
181175 (10.3%) 71175 (4.0%) 2.5 ± l.l
9/130 (6.9%) 101130 (7.7%) 3.0 ± 1.5
NS NS <0.01*
23/175 (13.5%) 2.5 ± l.l
37/130 (29.5%) 3.9 ± 3.8
0.002 <0.001*
241175 (13.7%)
451130 (33.2%)
0.0001
NS, Not significant. *Student t test.
Table V. Infection Amnionitis Endometritis Length of hospital stay (maternal, days) No. with stay >3 d:!ys Length of hospital stay (infant, days)t No. with stay >3 days NS, Not significant. *Mann-Whitney U. tRefiects maternal stay.
other newborn problems associated with the procedure. The incidence of both amnionitis and endometritis was not significantly different between the infusion and the control group. Interestingly, the length of hospital stay was significantly longer in the control group, a reflection of the increased rate of operative deliveries observed in this group (Table V). Comment
The role of amniotic fluid in providing a cushion for the fetal umbilical cord has now been suggested by several authors. 5 • 8 The results obtained in our study provide further evidence that the maintenance of adequate amniotic fluid volume is important during the intrapartum period. The apparent protection against cord compression seems to have a direct effect on both maternal and fetal outcome, and our results lend strong
support to the technique of amnioinfusion as a prophylactic treatment for oligohydramnios in labor. In a comparison of the methods of delivery (Tables II and III), it is readily apparent that the infusion group has a statistically significant increase in spontaneous vaginal deliveries and a subsequent decrease in operative deliveries. Operative intervention specifically because of fetal distress is also significantly reduced when one examines the overall rate (including forceps and vacuum) and when cesarean section alone is examined. Prior studies of cesarean section rates have suggested this trend but have not shown a statistical difference because of their smaller sample sizes. 2 • 5 This finding clearly translates to decreased maternal morbidity and a reduction in the number of cesarean deliveries. Of interest is the observation that operative vaginal deliveries because of fetal distress are higher in the study
Volume 165 Number 4, Part 1
population (both infused and noninfused patients) than in the general population at Women's HospitaL This is believed to reflect the complication of oligohydramnios in the study population. The observation that the rate did not return to normal in the infusion group suggests that in some patients oligohydramnios is a symptom of a larger problem, not simply corrected by amnioinfusion and restoration of a normal amniotic fluid index. With regard to fetal outcome, our data show a significant improvement in umbilical artery cord pH in the amnioinfused group. One-minute Apgar scores also were improved, but the 5-minute scores were not statistically different. Our results are similar to those reported in prior studies 2 . 5 and presumably reflect decreased stress in association with the elimination of repetitive variable decelerations. Of concern in our institution was the possible implication of amnioinfusion with increased rates of amnionitis and endometritis. Strong et aU reported a 13% increase in infection in his preliminary study of infused patients. This enlarged study failed to show a statistical difference between the infection rates between the control and treatment group, and the differences noted were only 3%. Recent work published by Owen et aU has suggested that amnioinfusion may actually provide a protective effect against maternal infection. Our work was unable to confirm this finding. Of great interest was the shortened length of hospital stay in the amnioinfusion group. While this finding is tied to the decreased rate of operative intervention for fetal distress, its importance is nonetheless diminished. In this era of rising medical costs, decreased hospital
Amnioinfusion for therapy of oligohydramnios in labor 975
time for both mother and infant would seem to provide further incentive for using this technique. In summary, this study shows that prophylactic amnioinfusion is a safe and simple technique that may be used for the treatment of oligohydramnios in patients in labor. Its benefits include a decrease in the rate of operative intervention for fetal distress, reduced rates of cesarean section, and decreased length of hospital stay. Amnioinfusion has no apparent adverse effects on the fetus or mother and does not appear to increase the rates of maternal infection. REFERENCES 1. Miyazaki FS, Taylor NA. Saline amnioinfusion for relief of variable or prolonged decelerations. AM] OBSTET GYNECOL 1983; 146:670-8. 2. Nageotte MP, Freeman RK, Garite T], Dorchester W. Prophylactic intrapartum amnioinfusion in patients with preterm premature rupture of membranes. AM] OBSTET GvNECOL 1985;153:557-62. 3. Miyazaki FS, Neverez F. Saline amnioinfusion for relief of repetitive variable decelerations: a prospective randomized study. AM] OBSTET GYNECOL 1985; 153:301-6. 4. Wenstrom KD, Parsons MT. The prevention of meconium aspiration in labor using amnioinfusion. Obstet Gynecol 1989;73:647-51. 5. Strong TH, Hetzler G, Sarno AP, Paul RH. Prophylactic intrapartum amnioinfusion: a randomized clinical trial. AM ] OBSTET GYNECOL 1990;162:1370-5. 6. Owen], Henson BV, Hauth]C. A prospective randomized study of saline solution amnioinfusion. AM] OBSTET GvNECOL 1990;162:1146-9. 7. Phelan]P, Ahn MO, Smith CV, Rutherford SE, Anderson E. Amniotic fluid index measurements during pregnancy. ] Reprod Med 1987;32:601-4. 8. Hon EH. Observations on "pathologic" fetal bradycardia. AM] OBSTET GYNECOL 1959;77: 1084-93.
Bound volumes available to subscribers Bound volumes of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY are available to subscribers (only) for the 1991 issues from the Publisher, at a cost of $61.00 for domestic, $88.27 for Canada, and $84.00 for international for VoL 164 (January-June) and VoL 165 (July-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the JOURNAL name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Mosby- Year Book, Inc., Subscription Services, 11830 Westline Industrial Drive, St. Louis, MO 63146-3318, USA; phone (800) 325-4177, ext. 4351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.