Obstet Gynecol.
1994 Jun;83(6):959-62.
Magann EF , Morton ML , Nolan TE , Martin JN Jr , Whitworth NS , Morrison JC .
Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson.
OBJECTIVE: To determine in pregnant women with preterm labor the relative efficacy of the amniotic fluid index (AFI) and the two-diameter pocket to detect abnormalities in amniotic fluid volume (AFV), and to relate these findings to pregnancy outcome. METHODS: Fifty-seven healthy women with preterm labor underwent amniocentesis in the third trimester to detect subclinical chorioamnionitis and assess fetal lung maturity. The AFV was estimated by the AFI and two-diameter-pocket methods, then confirmed by a dye (aminohippurate sodium)-dilution technique. Each labor was evaluated for severe variable decelerations requiring amnioinfusion, fetal distress resulting in cesarean delivery, and a 5minute Apgar score below 7. RESULTS: Using fluid volume confirmed by dye dilution, the AFI correctly diagnosed AFV as low (less than 500 mL) in only two of 23 (8.7%) patients, compared to 14 of 23 (61%) for the two-diameter pocket (P <
.001). Fetal distress requiring cesarean delivery occurred significantly more often in the hydramnios group (three of six) compared to those with normal AFV (one of 23) (P < .03), and approached significance in the oligohydramnios group
(two of 21) (P = .056). There were no significant differences among the three patient groups regarding the need for amnioinfusion for severe variable decelerations or the occurrence of 5-minute Apgar scores below 7. CONCLUSIONS:
Compared to the AFI, the two-diameter pocket is a superior sonographic measurement for the detection of oligohydramnios. In an otherwise low-risk pregnancy with preterm labor, oligohydramnios is associated with no greater risk for an adverse outcome than is a normal AFV.
PMID: 8190440 [PubMed - indexed for MEDLINE]
Am J Obstet Gynecol.
1992 Dec;167(6):1533-7.

Magann EF , Nolan TE , Hess LW , Martin RW , Whitworth NS , Morrison JC .

Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson 39216-4505.
Comment in:
Am J Obstet Gynecol. 1993 Aug;169(2 Pt 1):435-7.
OBJECTIVE: Our purpose was to determine amniotic fluid volume by the dye-dilution technique and compare it with the amniotic fluid index, largest vertical pocket, and two-diameter pocket (defined as vertical x horizontal of the largest vertical pocket). STUDY DESIGN: This prospective study involved 40 women undergoing amniocentesis in late pregnancy to detect fetal lung maturity or evidence of chorioamnionitis. The amniotic fluid volume was quantified ultrasonographically by means of the amniotic fluid index, largest vertical pocket, and two-diameter pocket. During amniocentesis the fluid volume was calculated by the dye-dilution technique of Charles and Jacoby. RESULTS:
Ultrasonographic measurements by amniotic fluid index, largest vertical pocket, and two-diameter pocket correctly predicted normal amniotic fluid and hydramnios (74%). A new measurement, two-diameter pocket, gave a significantly more accurate estimate of oligohydramnios than did amniotic fluid index (p < 0.002) or largest vertical pocket (p <
0.0003). CONCLUSION: All three indices are moderately accurate in identifying normal amniotic fluid volume and hydramnios. Two-diameter pocket is the most accurate test to predict oligohydramnios.
PMID: 1471660 [PubMed - indexed for MEDLINE]
Am J Perinatol.
2007 Oct;24(9):549-55. Epub 2007 Oct 1.
Magann EF , Chauhan SP , Doherty DA , Magann MI , Morrison JC .
Department of Obstetrics and Gynecology, Naval Medical Center-Portsmouth, Portsmouth, Virginia, USA.
This study assessed whether the amniotic fluid index (AFI) or the single deepest pocket (SDP) is the best technique to estimate amniotic fluid volume. The AFI and SDP were compared to a dye-determined or directly measured amniotic fluid volume. A PUBMED search from 1990 to 2006 was conducted using the search terms "single deepest pocket" or
"largest vertical pocket" or "maximum vertical pocket" or "2X1 pocket" AND "amniotic fluid index". One study compared

the AFI and SDP to a dye-determined amniotic fluid volume. There were 1219 publications that used the search term
SDP-LVP-MVP versus 4378 using AFI. Twenty publications contained both the AFI and SDP, but only six compared the
AFI and SDP. Both the AFI and the SDP poorly identified abnormal amniotic fluid volumes, and neither technique was superior to the other. The AFI identifies a significantly greater number of women as having oligohydramnios versus the
SDP but without any difference in perinatal outcomes. Compared with SDP, AFI excessively characterizes a greater number of pregnancies as having oligohydramnios leading to more interventions without improvement in perinatal outcome. The AFI should be abandoned and the SDP used to estimate amniotic fluid volume.
J Perinat Med.
1999;27(4):245-9.
Bianco A , Rosen T , Kuczynski E , Tetrokalashvili M , Lockwood CJ .
New York University Medical Center/Bellevue Hospital, Department of Obstetrics and Gynecology, New York, USA.
AIMS: The purpose of this study was to assess the effect, if any, of color Doppler on the measurement of the amniotic fluid index in term pregnancies. It is hypothesized that color Doppler may enhance the detection of oligohydramnios.
METHODS: The amniotic fluid index was performed with and without color Doppler on pregnancies greater than or equal to 36 weeks gestational age. Differences in the mean amniotic fluid index measurements were assessed. The incidence of oligohydramnios was examined using both techniques. Differences in continuous variables were assessed with the paired t test, differences in categorical variables were assessed using the Fisher Exact Test. RESULTS: There were 155 pregnancies examined, the amniotic fluid index was significantly decreased when color Doppler was added to the standard technique. (P < .0001) The incidence of oligohydramnios was higher with the application of color Doppler to the standard amniotic fluid index. (P < .05). CONCLUSIONS: Color Doppler results in a significantly lower amniotic fluid volume measurement and may enhance the detection of oligohydramnios.
PMID: 10560074 [PubMed - indexed for MEDLINE]
J Perinat Med.
1998;26(5):390-5.
Roberts D , Nwosu EC , Walkinshaw SA .
Department of Obstetrics and Gynaecology, Liverpool Women's Hospital, U.K.

Our aim was to assess the outcome of pregnancies where oligohydramnios, defined by a published gestational reference range for amniotic fluid index, was the only abnormal finding at third trimester scan, and all other ultrasound parameters including biometry were within normal limits at initial scan. A retrospective case-control study was performed at The
Liverpool Maternity Hospital. 103 pregnancies with reduced amniotic fluid index in the third trimester and apparently normal fetal growth profile ultrasonographically were identified from ultrasound reports throughout 1993. Pregnancies in the third trimester with normal amniotic fluid index on index scan were also identified from these reports and 103 were matched for parity, gestational age at delivery, mode of onset of labour, presentation at labour and medical conditions.
Exclusion criteria were ruptured membranes, fetal abnormalities, estimated fetal weight below the fifth centile at index scan and multiple pregnancies. The outcome criteria were birthweight, Apgar scores at delivery, induction and emergency delivery for fetal reasons and admission to Neonatal Intensive Care Unit. Statistical analysis was performed by Fisher's exact test and Gart's odds ratio. Compared with controls, pregnancies in the reduced liquor group had a higher number of babies below the 5th centile (odds ratio 5.2, 95% confidence interval 1.6 to 22), a higher risk of induction for fetal reasons (odds ratio 34.4, 95% confidence interval 5.35 to 1425.5) and admission to Neonatal Intensive
Care Unit (odds ratio 9.77, 95% confidence interval 1.3 to 432). Any observed difference in the need for emergency delivery due to fetal reasons was not clinically significant (odds ratio 2.16, 95% confidence interval 0.77 to 6.6) The definition used for oligohydramnios used in this study appears to identify a group of babies with a fourfold risk of low birthweight and a high risk of admission to the Neonatal Intensive Care Unit and induction of labour for fetal reasons.
This would suggest that pregnancies with isolated oligohydramnios require some form of fetal monitoring and further prospective studies are required to determine the most appropriate method.
PMID: 10027135 [PubMed - indexed for MEDLINE]
J Reprod Med.
2007 Apr;52(4):293-8.
Barrilleaux PS , Magann EF , Chauhan SP , York BM , Philibert L , Lewis DF .
Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson 39216-4505, USA. jmorrison@ob-gyn.umsmed.edu
OBJECTIVE: To evaluate the prognostic value of an amniotic fluid index (AFI) < or = 5 cm for an adverse perinatal outcome in pregnancies with the syndrome of hemolysis, elevated liver enzymes and low platelets (HELLP syndrome).
STUDY DESIGN: A prospective, observational study of patients with the HELLP syndrome. An ultrasound estimate of

amniotic fluid volume was obtained on admission. Adverse intrapartum outcomes included amnioinfusion for variable decelerations and/or indicated abdominal/vaginal operative delivery for nonreassuring fetal heart rate changes. Maternal characteristics and perinatal outcome parameters were compared AFI < or = vs. > 5 cm. Statistical analysis was performed using chi2 analysis, Student's t test and receiver-operator characteristic curve (ROC) analysis. RESULTS:
Between January 1996 and February 1999, 120 patients were enrolled. Twenty-six (22%) had an AFI < or = 5 cm. This group did not differ from that with AFI > 5 cm regarding the severity of the HELLP syndrome, admission-to-delivery interval (p = 0.354), variable decelerations in labor (p = 0.06), Apgar score of < 7 at 5 minutes (p = 0.361), cesarean delivery for nonreassuring fetal status (p = 1.0) or significant fetal acidosis (pH < 7.0 [p = 0.2101). ROC analysis revealed no AFI measurement between 0 and 16 cm that was useful for identifying the compromised fetus. CONCLUSION:
Antepartum/intrapartum performance of AFI in patients with the HELLP syndrome is a poor prognostic test for subsequent fetal compromise.
PMID: 17506369 [PubMed - indexed for MEDLINE]
J Reprod Med.
2006 Jun;51(6):484-8.
Lam H , Leung WC , Lee CP , Lao TT .
Department of Obstetrics and Gynaecology, University of Hong Kong, Queen Mary Hospital, Hong Kong SAR. lamswh@yahoo.com.hk
OBJECTIVE: To assess the usefulness of amniotic fluid index (AFI) in the assessment of postdate pregnancies. STUDY
DESIGN: A prospective, observational study was carried out on the AFI of 118 well-dated postdate pregnancies at 41 weeks within 2 days of delivery. The AFI quartile distribution was determined and correlated with the risk of thick meconium-stained liquor (MSL), intervention for fetal distress and admission to the special care baby unit (SCBU).
RESULTS: The median AFI was 8 cm, with a range from 1-33 cm. There was a significant inverse correlation between the occurrence of thick MSL, intervention for fetal distress and SCBU admission. Logistic regression analysis, upon adjusting for possible confounding factors, showed that only AFI in the 2 lower quartiles combined (< or = 8 cm) had a significant association with the risk of thick MSL (adjusted OR 11.0, 95th CI 2.43-49.8) but not admission to the SCBU.
AFI in the lowest quartile (< or = 5 cm) had a significant association with the risk of intervention for fetal distress only
(adjusted OR 7.95, 95th CI 1.67-37.7). CONCLUSION: Although AFI may be used to predict the occurrence of thick MSL and the need for intervention for fetal distress in postdate pregnancies, its role on its own is limited.

PMID: 16846088 [PubMed - indexed for MEDLINE]
J Reprod Med.
2001 Jun;46(6):589-92.
Rainford M , Adair R , Scialli AR , Ghidini A , Spong CY .
Department of Obstetrics and Gynecology, Georgetown University Hospital, Washington, D.C., USA.
OBJECTIVE: To establish whether an association between oligohydramnios and pregnancy outcome is present in the uncomplicated term pregnancy. STUDY DESIGN: Pregnancies with a singleton fetus in cephalic presentation at term (> or = 37 weeks), a reactive non-stress test and an antepartum amniotic fluid index performed within four days of delivery between January 1994 and September 1998 were identified. Excluded were those with any maternal or fetal complication or unavailable outcome information. The primary outcome measure was rate of operative vaginal or abdominal delivery for a nonreassuring fetal heart rate tracing. Statistical analysis included Fisher's exact test and oneway analysis of variance, with a two-tailed P < .05 considered significant. RESULTS: Two hundred thirty-two women met the inclusion criteria; of them, 44 (19%) had an amniotic fluid index < or = 5 cm. There was no difference in the operative delivery rate for a nonreassuring fetal heart tracing between those with a normal amniotic fluid index > 5 cm vs. < or = 5 cm (39 [21%] vs. 5 [11%], P > .05). In addition, there were no differences between the two groups in rates of neonatal intensive care unit admissions or five-minute Apgar scores < 7. Patients with a normal amniotic fluid index had a significantly lower labor induction rate (96 [51%] vs. 42 [98%], P < .001) and higher rate of meconium-stained amniotic fluid (65 [35%] vs. 7 [16%], P = .01) than those with a low amniotic fluid index. CONCLUSION: In the uncomplicated pregnancy at term, an amniotic fluid index < or = 5 cm increases the incidence of labor induction but does not appear to affect the rate of operative delivery for abnormal fetal heart rate tracings.
PMID: 11441685 [PubMed - indexed for MEDLINE]
Gynecol Obstet Invest.
2002;53(1):1-5.
Kawasaki N , Nishimura H , Yoshimura T , Okamura H .
Department of Obstetrics and Gynecology, Shimonoseki Kosei Hospital, Japan. nori-kawasaki@hkg.odn.ne.jp

OBJECTIVE: To determine whether a diminished intrapartum amniotic fluid volume represents a risk of adverse neonatal outcome when it occurs in conjunction with prolonged labor. METHODS: The intrapartum amniotic fluid index (iAFI) was measured in 242 parturients over 35 weeks of gestation during 1st-stage labor, and the umbilical artery blood gas was analyzed at delivery. The subjects were divided into group A (n = 99), having a diminished amniotic fluid volume (iAFI < or = 8.0 cm) and group B (n = 143), having a normal amniotic fluid volume (iAFI 8.1-20.0 cm), and selected antenatal, delivery, and neonatal variables were compared. In addition, the two groups were subdivided according to the duration of labor. Statistical analysis was performed using independent Student's t test, Mann-Whitney U test, chi-square analysis, and Fisher's exact test where appropriate. p < 0.05 was considered significant. RESULTS: The patient characteristics and pregnancy outcomes were similar in groups A and B, as were the incidences of an umbilical artery blood pH <7.20 and/or an Apgar score <7 (group A 9.5%, group B 10.1%). In group A, however, the incidence of an adverse neonatal outcome was 23.5% in cases in whom the duration of labor was longer than 8 h which was significantly higher than in cases in whom the duration of labor was 8 h or less (2.8%; p < 0.01). In group B, the incidence of an adverse neonatal outcome was similar in the two subgroups. CONCLUSIONS: The risk of an adverse neonatal outcome is higher in patients with diminished amniotic fluid volume if labor is prolonged. Consequently, determination of the iAFI could be a useful admission test. Copyright 2002 S. Karger AG, Basel
PMID: 11803220 [PubMed - indexed for MEDLINE]
Gynecol Obstet Invest.
1998;45(1):19-23.
Ergün A , Atay V , Pabuçcu R , Başer I , Duru NK , Tokaç G .
Department of Obstetrics and Gynecology, Gülhane School of Medicine, Ankara, Turkey.
Amniotic fluid volumes were measured in 1,659 pregnant women to determine the predictive value of these measurements on perinatal outcome. All cases were evaluated by other tests of fetal well-being. 128 cases were oligohydramniotic, and 1,531 cases were normal. In all cases, several parameters were assayed, e.g. fetal distress, way of delivery, meconium in amniotic fluid, Apgar score, transfer to pediatric clinics and early-late neonatal complications.
The results of the perinatal evaluation of oligohydramnios were as follows: assessing fetal distress: specificity 94.2%, sensitivity 18.4%, positive predictive value 35.9%, negative predictive value 86.7% and accuracy 82.8%, and assessing low Apgar score the values were 93.0, 21.3, 95.9 and 89.5%, respectively. As a result, measurement of the amniotic fluid volume is an important parameter predicting perinatal outcome, and its predictive value increases if it is combined with other fetal well-being tests with different end points.

PMID: 9473158 [PubMed - indexed for MEDLINE]
J Perinatol.
1997 May-Jun;17(3):221-4.
Chauhan SP , Magann EF , Perry KG Jr , Morrison JC .
Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson 39216-4505, USA.
OBJECTIVE: The objective of this study was to determine whether amniotic fluid index < or = 5.0 cm or two-diameter pocket volume < or = 15 cm2 is a predictor of abdominal delivery because of fetal distress or of Apgar score < 7 at 1 or 5 minutes. STUDY DESIGN: The study was prospective and involved 209 parturients in early labor who had ultrasonographic assessment of amniotic fluid volume by both methods. RESULTS: The incidences of cesarean delivery because of fetal distress and of Apgar scores < 7 at 1 and 5 minutes were 8.1%, 9.0%, and 1.9%, respectively. Only
Apgar scores < 7 at 1 minute were significantly higher among patients with a two-diameter pocket < 15 cm2 (16/114) as compared with > 15(2) (3/95, p = 0.007). Oligohydramnios by either method was a poor predictor of adverse outcomes (p values ranging from 0.06 to 0.21). Receiver-operating characteristic curves generated for the amniotic fluid index or twodiameter pocket to predict abdominal delivery because of fetal distress or Apgar scores < 7 at 1 minute indicate that both methods are poor diagnostic tests to predict these complications. CONCLUSION: Intrapartum assessment of amniotic fluid volume, by amniotic fluid index or the two-diameter pocket technique, is a poor predictor of adverse neonatal outcome.
PMID: 9210079 [PubMed - indexed for MEDLINE]
J Miss State Med Assoc.
1998 Jan;39(1):6-9.
Chauhan SP , Magann EF , Cowan BD , Perry KG Jr , Morrison JC .
Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson 39216-4505, USA.
PURPOSE: To describe a predictable relationship that relates amniotic fluid index (AFI) to amniotic fluid volume (AFV) and improve the accuracy of AFI to detect true oligohydramnios. METHODS: Data from 42 parturients (group I) who underwent measurements of amniotic fluid sonographically (amniotic fluid index) as well as by dye-dilution technique was

used to relate AFI to AFV. Subsequently, 22 consecutive women (group II) were used to test the accuracy of the equation to predict true oligohydramnios. RESULTS: In group II, 11 of 22 patients had true oligohydramnios and the sensitivity, specificity, positive and negative predictive values of AFI < or = 5.0 to detect a confirmed AFV < 500 mL were
0%, 91%, 0%, and 48%, respectively. These values of AFI, when used in conjunction with the equation, improved to
73%, 55%, 62%, 67%, respectively. With AFI and the equation, significantly more patients in group II with true oligohydramnios (8 of 11) could be detected than with using AFI alone (0 of 11; p = 0.002). CONCLUSION: AFI is poor predictor of true oligohydramnios. Using the mathematical model, the detection rate of oligohydramnios is significantly improved.
PMID: 9448386 [PubMed - indexed for MEDLINE]
J Miss State Med Assoc.
1999 Feb;40(2):43-6.
Chauhan SP , Roberts WE , Martin JN Jr , Magann EF , Morrison JC .
Department of Obstetrics and Gynecology, Spartanburg Regional Healthcare System, South Carolina, USA.
OBJECTIVE: This longitudinal study was undertaken to characterize the change in the amniotic fluid volume in normal pregnancy. METHODS: Prospectively, patients with uncomplicated gestations underwent serial amniotic fluid index by a single sonographer. RESULTS: Fifty-six patients underwent a total of 378 determinations of amniotic fluid volume (6.8 +/-
2.5 examinations per patient). The variation in mean amniotic fluid index between 24 and 40(+6) weeks was not significantly different (p = 0.381). Among the 42 patients who delivered at term there was no significant decrease in the amniotic fluid index between their first and last measurement (p = 0.86). However, in the 14 patients who delivered after
41 weeks, there was a significant decrease in the index over time (p = 0.04). CONCLUSION: The longitudinal study on amniotic fluid volume in normal pregnancy reveals that amniotic fluid index does not change significantly with gestational age.
PMID: 10024790 [PubMed - indexed for MEDLINE]
J Ultrasound Med.
1995 Dec;14(12):895-7.
Magann EF , Whitworth NS , Klausen JH , Perry KG Jr , Martin JN Jr , Morrison JC .

Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson 39216-4505, USA.
The purpose of this investigation was to evaluate the accuracy of common sonographic techniques in assessing the amniotic fluid volume in pregnancies of less than 24 weeks' gestation. Patients at less than 24 weeks' gestation undergoing an amniocentesis for the placement of prostaglandin F2 alpha for termination (because of genetic or fetal anomalies, or both) were assessed for amniotic fluid volume. All fetuses were alive at the time of prostaglandin instillation. The amniotic fluid index and two-diameter pocket were used to determine the amniotic fluid volume. Prior to the prostaglandin instillation, the amniotic fluid volume was determined with para-aminohippurate using a diazo dye reaction with spectrophotometric analysis. The amniotic fluid volume was determined in 21 pregnancies between 15 and
24 weeks' gestation, yielding volumes ranging from 189 to 1840 ml. Using published standards for amniotic fluid volume in singleton pregnancies, oligohydramnios was present in three gestations, the volume was found to be normal in 15, and hydramnios complicated three pregnancies. The two-diameter pocket identified the amniotic fluid volumes correctly more often (18 of 21 [85.7%]) than the amniotic fluid index (10 of 21 [47.6%]) (P = 0.02). Normal amniotic fluid volume was identified in nine of 15 (60%) pregnancies by the amniotic fluid index and in 14 of 15 (93.3%) by the two-diameter pocket
(P = not significant). Abnormal amniotic fluid volumes, oligohydramnios, and hydramnios were recognized more often by the two-diameter pocket (66.7%) than by the amniotic fluid index (1 of 6 [16.7%], P = not significant).
PMID: 8583524 [PubMed - indexed for MEDLINE]