Amniotic fluid index as indicator for pregnancy outcome in late third trimester
DOI:
https://doi.org/10.18203/2320-1770.ijrcog20232956Keywords:
Amniotic fluid index, Ultrasound image segmentation, Deep learningAbstract
Background: Amniotic fluid index is one of the major predictors of pregnancy outcome. Less AFI indicate growth restriction and renal anomalies of fetus, whereas more may indicate fetal GI anomalies, maternal diabetes mellitus, and so forth. Objectives were to establish reference standards for AFI for local population after 34 weeks of pregnancy and to decide an optimal scan interval for AFI estimation in third trimester in low-risk antenatal women.
Methods: A prospective estimation of AFI was done in 83 healthy low risk pregnant women from 34 to 40 weeks at weekly intervals. The trend of amniotic fluid volume was studied with advancing gestational age. Statistical analysis was done using SPSS software (Version 16, Chicago, IL). Percentile curves (5th, 50th, and 95th centiles) were constructed for comparison with other studies. Cohen’s d coefficient was used to examine the magnitude of change at different time intervals.
Results: Starting from 34 weeks till 40 weeks, 83 ultrasound measurements were available. The mean (standard deviation) of AFI values (in cms) were 34W:14.59(1.79), 35W: 14.25 (1.57), 36W: 13.17 (1.56), 37W: 12.48 (1.52), 38W: 12.2 (1.7), and 39W: 11.37 (1.71). The5th percentile cut-off was 8.7 cm at 40 weeks. There was a gradual decline of AFI values as the gestational age approached term. Significant drop in AFI was noted at two-week intervals.
Conclusions: Appreciable changes occurred in AFI values as gestation advanced by two weeks. Hence, it is recommended to follow up low risk antenatal women every two weeks after 34 weeks of pregnancy.
References
Morris JM, Thompson K, Smithey J, Gaffney G. The usefulness of ultrasound assessment of amniotic fluid in predicting adverse outcome in prolonged pregnancy. Br J Obst Gynaecol. 2003;110:989-94.
Chauhan SP, Doherty DA, Magann F. Amniotic fluid index versus single deepest pocket technique during modified biophysical profile. A randomized clinical trial. Am J Obstet Gynaecol. 2004;191:661-8.
Yeo L, Ross MG, Vintzileo AM. Antepartum and intra-partum surveillance of the foetus and the amniotic fluid. Clin Obstet Fetus Mother. 2008;3:586-606.
Liston R, Sawchuck D, Young D. Fetal health surveillance: antepartum and intrapartum consensus guideline. J Obstet Gynaecol Canada. 2007;29:56.
Baschat AA, Viscardi RM, Hussey GB, Hashmi N, Harman C. Infant neurodevelopment following fetal growth restriction: Relationship with antepartum surveillance parameters. Ultrasound Obstet Gynaecol. 2009;33:44-50.
Nash P. Amniotic fluid index. Neonat Net. 2013; 32:46-9.
Dubil EA. Amniotic fluid as a vital sign for fetal wellbeing. Austral J Ultrasound Med. 2013;16(2):62-70.
Nabhan AF, Abdelmoula YA. Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome. Cochrane Database Syst Rev. 2008;3:65-93.
Phelan JP, Ahn MO, Smith CV, Rutherford SE, Anderson E. Amniotic fluid index measurements during pregnancy. J Reprod Med. 1987;32(8):601-4.
Beall MH, van den Wijngaard JP, van Gemert MJ, Ross MG. Amniotic fluid water dynamics. Placenta. 2007;28(8-9):816-23.
Broussard P, Phelan JP, Smith CV, Small M. Amniotic fluid volume assessment with the four-quadrant technique at 36-42 weeks' gestation. J Reprod Med. 1987;32(7):540-2.
Iqbal S, Noreen A. Low amniotic fluid index as a predictor of perinatal outcome in low-risk pregnancies at term. Pakistan J Med Health Sci. 2010;4(3):270-1.
Voxman EG, Tran S, Wing DA. Low amniotic fluid index as a predictor of adverse perinatal outcome. J Perinatol. 2002;22(4):282-5.
Lalor JG, Fawole B, Alfirevic Z, Devane D. Biophysical profile for fetal assessment in high-risk pregnancies. Cochrane Database Syst Rev. 2008.
Signore C, Freeman RK, Spong CY. Antenatal testing-a revaluation: executive summary of a Eunice Kennedy Shriver National Institute of Child Health and Human Development workshop. Obstet Gynaecol. 2009; 113(3):687-701.
Khadilkar SS, Desai SS, Tayade SM, Purandare CN. Amniotic fluid index in normal pregnancy: an assessment of gestation specific reference values among Indian women. J Obstet Gynaecol Res. 2003; 29(3): 136-41.
Cohen J. Statistical Power Analysis for the Behavioural Sciences. USA: Hillsdale; 1988.
Brace RA, Wolf EJ. Normal amniotic fluid volume changes throughout pregnancy. Am J Obstet Gynaecol. 1989;161(2):382-8.
Moore JT, Cayle RE. The amniotic fluid index in normal human pregnancy. Am J Obstet Gynaecol. 1990;162(5):1168-73.
Magann EF, Sandlin AT, Ounpraseuth ST. Amniotic fluid and the clinical relevance of the monographically estimated amniotic fluid volume: oligohydramnios. J Ultrasound Med. 2011;30(11):1573-85.
Lee SM, Park SK, Shim SS, Jun JK, Park JS, Syn HC. Measurement of fetal urine production by three-dimensional ultrasonography in normal pregnancy. Ultrasound Obstetr Gynaecol. 2007;30(3):281-6.
Singh C, Tayal T, Gupta R, Sharma AP, Khurana D, Kaul A. Amniotic fluid index in healthy pregnancy in an Indian population. Int J Gynaecol Obstet. 2013; 121(2):176-7.
Rosenthal R, Rosnow RL. Essentials of Behavioural Research: Methods and Data Analysis. 2nd ed. USA: McGraw Hill; 1991.
Richardson JTE. Eta squared and partial eta squared as measures of effect size in educational research. Edu Res Rev. 2011;6(2):135-47.
