1. AMNIOTIC FLUID DISORDERS
Ümit Görkem,MD
Hitit University Faculty of Medicine
Obstetrics and Gynecology
Çorum

2. The composition of amniotic fluid
proteins (albumins & globulins),
lipids (phospholipids, cholesterol and lecithin),
carbohydrates (predominantly glucose),
inorganic salts,
cells derived from fetal epithelium, amniotic membrane, & dermal fibroblasts.
(This latter cell type grows well in culture and is frequently used for karyotyping).

6. The perinatal mortality rate (PMR) approaches 90% to 100% with severe oligohydramnios in the second trimester.
PMR can exceed 50% with significant polyhydramnios in midpregnancy .

7. Amniotic Fluid Formation
Fetal Urine
The main source of AF is fetal urination.
Human fetal urine- production rate appears to be approximately to 1200 mL/day at term, which suggests that the entire AFV is replaced more frequently than every 24 hours.

8. Lung Liquid
The trachea acts as a one-way valve in most situations preventing amniotic fluid from entering the lungs [1].
In fetal sheep experiments, the lungs have been reported to produce volumes of up to 400 mL/day, with 50% being swallowed and 50% exiting via the mouth. [2,3].
Although we do not have direct measurements in humans, the presence of surfactant in the AF near term provides evidence for the outward flow of lung liquid.
1- Dubil et al. AJUM 2013:16,2
2- Adamson TM, et al. Foetal and Neonatal Physiology. 1973Cambridge University Press Cambridge, UK 208
3- Brace RA, et al.Am J Obstet Gynecol. 1994;171:764 

9. Amniotic Fluid Removal
Fetal Swallowing
In the human, fetal swallowing begins early in gestation and contributes to the removal of AF.
Human fetal swallowing was studied by injecting radioactive chromium-labeled erythrocytes and hypaque into the amniotic compartment, and swallowing rates of 72 to 262 ml/kg/day were found.

10. Intramembranous Absorption
This process describes the movement of water and solutes between the amniotic compartment and the fetal blood, which circulates through the fetal surface of the placenta.
Researchers have noted that 200 to 500 mL/day leaves the amniotic compartment under normal physiologic conditions [4,5].
4- Gilbert WM , RA Brace. Obstet Gynecol. 1989;74:748 
5- Brace RA , et al.Am J Physiol Regul Integr Comp Physiol. 2014;307 (10):R1260-R1273 

13. Measurement of amniotic fluid volume
made directly, indirectly, or estimated sonographically.
Direct measurement is done at the time of cesarean or uterine hysterotomy [6].
Indirect measurement is done via amniocentesis by dye-dilution techniques. Dye-dilution using para-amino hippurate has been shown to be representative of actual AFV obtained by direct measurement at the time of cesarean delivery [7].
6-Horsager R, et al. Obstet Gynecol 1994; 83: 955–58.
7-Magann EF, et al. J Matern Fetal Neonatal Med 2002; 11: 167–70.

14. Because these techniques to measure amniotic fluid volume are time consuming, invasive, and may require laboratory support, amniotic fluid volumes are usually estimated by ultrasound.
Magnetic resonance imaging (MRI) has also been evaluated as a means for estimating AFV [8]; however, this is an impractical approach to everyday screening.
8-Zaretsky MV, et al. Am J Obstet Gynecol 2004; 191: 2148–53.

15. There are four methods of sonographic evaluation of amniotic fluid volume:
subjective assessment,
2 x 2 measurement,
single deepest pocket (SDP), which is also known as maximum vertical pocket (MVP),
amniotic fluid index (AFI).

16. Amniotic fluid index first proposed by Phelan and Rutherford
the summation of the vertical diameter of the largest pocket in each of the four quadrants with the maternal umbilicus as a central reference point [9].
The transducer should be oriented in the longitudinal plane and there should be a minimum horizontal measurement of one centimeter for each pocket.
9-Phelan JP, et al. J Reprod Med 1987; 32: 540–42.

17. Single deepest vertical pocket
proposed by Chamberlain
simply found by identifying the largest pocket of amniotic fluid after a global assessment and selecting the largest vertical measurement with a minimum horizontal measurement of one centimeter [10].
Two-diameter pocket (cm2) is calculated by multiplying the depth and width of the largest single pocket [11,12].
10-Chamberlain PF, et al. Am J Obstet Gynecol 1984; 150: 250–54.
11-Johnson JM, et al. Am J Obstet Gynecol 1986; 154: 269–73.
12-Magann EF, et al. Am J Obstet Gynecol 1992; 167: 1533–37.

22. Normal volume
Ulker et al. demonstrated that detectable changes in AFI (and fetal urine output) can occur within an hour or so of initiation of a maneuver such as hydration, rest, or maternal positioning[13,14].
These findings may help explain the inconsistency of results when tests are repeated within hours of each other or performed by different operators.
13- Ulker K, et al. J Ultrasound Med 2011;30:481e6.
14- Ulker K, et al. J Reprod Med 2012;57:270e6.

25. The Nabhan Cochrane meta-analysis included five randomized trials comparing AFI (oligo definition of less than 5 cm) versus SPE (2 cm _ 1 cm pocket) [16].
No differences in pH <7.0, low Apgar scores, neonatal intensive-care unit admission, non- reassuring fetal heart rate tracing, meconium, or CS rates were seen.
The use of AFI, however, resulted in significant differences in diagnosis of oligohydramnios and rate of induction of labour and CS for fetal distress.
15- Nabhan AF, et al. Cochrane Database Syst Rev 2008;(3):CD

28.   OLIGOHYDRAMNIOS
Oligohydramnios has been defined as an AFV that is less than 200 mL or 500 mL [16].
By ultrasound techniques, it has been estimated as;
a SDP less than 2 cm [17],
an AFI less than 5 cm [18],
an AFI below the 5th percentile for gestational age [19],
a subjectively low AFV [20].
16-Dildy GA 3rd, et al. Am J Obstet Gynecol 1992; 167: 986–94.
17-Chamberlain PF, et al. Am J Obstet Gynecol 1984; 150: 245–49.
18-Phelan JP, et al. J Reprod Med 1987; 32: 540–42.
19-Chauhan SP, et al. Am J Obstet Gynecol 2004; 191: 661–67.Discussion 7–8.
20-Magann EF, et al. J Clin Ultrasound 1997; 25: 249–53.

29. Borderline fluid between 5–8 cm or 5–10 cm
been associated with fetal malformations if diagnosed at age 24–34 weeks [20,21].
21-Petrozella LN, et al. Obstet Gynecol 2011; 117: 338–42.
22-Magann EF, et al. J Ultrasound Med 2011; 30: 523–28.

30. The incidence of oligohydramnios varies depending on which definition is used, with a general reporting rate between 1 and 3%.
When women undergoing antepartum testing for high-risk pregnancy conditions are examined, the incidence of oligohydramnios is much higher (19 to 20%).
In clinical practice, an MVP less than 2 cm or an AFI less than 5 cm are commonly used as criteria for the diagnosis of oligohydramnios.

32. Evaluation and Treatment of Oligohydramnios
When the diagnosis of oligohydramnios is made in the second trimester, it is vitally important to obtain a complete history and physical exam and to perform a targeted ultrasound to help identify a cause.

33. If there is a question of possible rupture of the membranes (ROM),
Specific tests include evidence of ferning on microscopy examination, a neutral pH on nitrazine paper, and pooling of fluid in the posterior vagina.
Commercial tests : AmniSure (Qiagen, Hilden, Germany) and ROM Plus (Clinical Innovations, Murray, Utah), which check for certain proteins from the AF in the vagina.

34. Although severe oligohydramnios has an increased PMR later in the third trimester, it is still not as high as earlier in pregnancy [22,23].  It is reported a 50-fold increase in PMR when the LVP of AF was less than 1 cm.
22- Mercer LJ, et al. Obstet Gynecol. 1986:67;840
23- Casey BM,et al. Am J Obstet Gynecol. 2000: 182;909  

35. Management of Oligohydramnios
Many other studies have shown an improvement in AFV with either oral or intravenous administration of water and/or crystalloids [24].
Several researchers have reported success in improving AFV in women with oligohydramnios by the injection of a crystalloid solution into the amniotic compartment during an amniocentesis [25,26].
24-Flack NJ, et al. Am J Obstet Gynecol. 1995;173:  
25-Doi S, et al. Obstet Gynecol. 1995;92:525 
26-Sepulveda W, et al. Am J Obstet Gynecol.1994; 170:1160 

36. It is worth remembering that oligohydramnios may appear idiopathic at diagnosis, but may be a sign of an anomaly not detected until after birth.
Chromosomal anomalies have been found in 13% of pregnancies with oligohydramnios [27], and late diagnosis of oligohydramnios in pregnancies with normal anatomy has also been found to be associated with undiagnosed renal anomalies up to 9.8% of the time [28].
27-Stoll C, et al. Community Genet 1998; 1: 71–77.
28-Leibovitch L, et al. Acta Paediatr 2012; 101: 727–30.

37. Oligohydramnios in Labor
Multiple investigators have studied amnioinfusion as a technique by which to treat variable decelerations in labor. 
Although most report a decrease in the frequency of variable decelerations, few have demonstrated any decrease in perinatal morbidity or mortality or in the cesarean delivery rate [29,30,31].
29-Nageotte MP, et al. Obstet Gynecol.1991;77:677 
30-Ogundipe OA, et al. Obstet Gynecol.1994; 84:544 
31-Schrimmer DP, et al. Am J Obstet Gynecol 1991; 165:972 

38. A more recent, multicenter, randomized trial of women in labor at 36 weeks’ gestation or later with thick meconium did not find that amnioinfusion reduced the risk of moderate or severe meconium aspiration syndrome or perinatal death [32].
Based on this large multicenter trial, ACOG recommends against routine prophylactic amnioinfusion for the dilution of meconium– stained amniotic fluid [33].
32-Fraser WD, et al. N Engl J Med. 2005;353:909
33-ACOG Committee on Obstetric Practice: Committee Opinion No. 346: Amnioinfusion does not prevent meconium aspiration syndrome. 2014

40. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists recommend a pregnancy with oligohydramnios be referred to a specialist Obstetrician [34].
The American College of Obstetrics and Gynecology indicates that oligohydramnios may be an indication for induction of labour [35].
The Society of Obstetricians and Gynaecologists of Canada states that antepartum testing may be beneficial [36].
34-RANZCOG. Maternal suitability for models of care, and indications for referral within and between models of care (C-Obs 30)
35-Practice Bulletin No AC. 107: Induction of labor. Obstet Gynecol 2009; 114: 386–97.
36-ACOG practice bulletin. Antepartum fetal surveillance. Int J Gynaecol Obstet 2000; 68: 175–85.

41. POLYHYDRAMNIOS
Polyhydramnios has been defined as an AFV of greater than 2000 mL [37].
By ultrasound techniques, it has been estimated as
SDP greater than 8 cm [38],
AFI greater than 25 cm [39],
above the 95th percentile for gestational age [40],
subjectively high AFV [41].
37-Magann EF, et al. Obstet Gynecol 1994; 83: 959–62.
38-Chamberlain PF, et al. Am J Obstet Gynecol 1984; 150: 245–49.
39-Baron C, et al. Am J Obstet Gynecol 1995; 173: 167–74.
40-Moore TR, et al. Am J Obstet Gynecol 1990; 162: 1168–73.
41-Magann EF, et al. J Clin Ultrasound 1997; 25: 249–53.

43. The incidence of polyhydramnios is 1% to 2%
The incidence of polyhydramnios is 1% to 2%. The earlier in gestation polyhydramnios occurs and the greater the amount of fluid, the higher the perinatal morbidity and mortality [42].
Hill and colleagues divided their patients with polyhydramnios into three groups [43].  
mild (MVP 8 to 11 cm), 
moderate (MVP 12 to 15 cm),
 severe (MVP ≥16 cm).
42-Wier PE, et al. Br J Obstet Gynaecol. 86:849 197
43-Hill LM, et al. Obstet Gynecol. 69:21 1987

45. Severe polyhydramnios in the second trimester has a significant PMR due to prematurity or aneuploidy [44,45].  
Pregnancy complications associated with polyhydramnios have been reported to increase the risk for placental abruption and postpartum hemorrhage as a result of overdistension or rapid deflation of the uterus.
44-Pauer HU, et al. Arch Gynecol Obstet. 2003;268:52 
45-Desmedt EJ, et al. Br J Obstet Gynaecol. 1990;97:1115 

46. Evaluation and Treatment of Polyhydramnios
Management of pregnancies with polyhydramnios, if identified early, should include;
sonographic evaluation for anatomical causes,
evaluation for maternal diabetes,
TORCH serology testing,
consideration of isoimmunisation as a cause.
If polyhydramnios is present with a growth restricted fetus, evaluation for chromosomal abnormalities should be undertaken [46].
46-Barnhard Y, et al. Am J Obstet Gynecol 1995; 173: 1523–27.

47. The pregnant woman who presents with a rapidly enlarging uterus in mid pregnancy, with or without preterm labor, needs to be evaluated by an ultrasound examination to measure the AFV and assess fetal anatomy.
When a structural defect is seen in a fetus with polyhydramnios, consideration should be given to performing an amniocentesis for microarray analysis.

48. Antenatal testing should be initiated at 24 weeks gestation, although there is no consensus on what type of testing should be begun, or at what interval [47].
Therapeutic approaches to polyhydramnios include amnioreduction and the use of indomethacin, which have been studied in randomized controlled trials.
Comparisons of rapid versus slow drainage, large volume versus repeated small volumes, and the use of tocolysis during amnioreduction have not shown significant differences.
47-O’Neill E, Thorp J. Clin Obstet Gynecol 2012; 55: 722–30.

49. As amniotic fluid is removed, expansion of the placenta drains blood from the fetus, which can cause long-term central nervous system and cardiac injury.
Serial amniodrainage has been successfully conducted in a number of cases, reducing the impact of prematurity.
This benefit must be weighed against the potential risk to mother and fetus should aggressive preterm labor or placental abruption follow the procedure.

50. With severe polyhydramnios associated with preterm labor, one medical treatment option involves the administration of a prostaglandin inhibitor such as indomethacin, which decreases fetal urine production [48,49].
48-Stevenson KM, et al. J Dev Physiol. 1992;17:257
49-Mamopoulos M, et al. Am J Obstet Gynecol. 1990;162:1225 

51. narrowing of the ductus arteriosus within the fetal heart,
Although indomethacin has been shown to be relatively safe when given over a short period of time, such as 72 hours, prolonged use may be associated with risks to the fetus such as
premature closure,
narrowing of the ductus arteriosus within the fetal heart,
renal abnormalities in the newborn period [50,51].
50-Kirshon B, et al. Obstet Gynecol. 1988;72:51 
51-Mamopoulos M, et al. Am J Obstet Gynecol. 1990;162:1225 

52. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists recommend a pregnancy with polyhydramnios be referred to a specialist Obstetrician [52].
There are currently no practice management recommendations from the American College of Obstetrics (ACOG), Royal College of Obstetrics and Gynaecology (RCOG) or the Society of Obstetricians and Gynaecologists of Canada (SOGC) beyond the statement that antepartum testing may be beneficial by ACOG and SOGC [53,54].
52-RANZCOG. Maternal suitability for models of care, and indications for referral within and between models of care (C-Obs 30)
53-ACOG practice bulletin. Antepartum fetal surveillance.. Int J Gynaecol Obstet 2000; 68: 175–85.
54-Liston R, et al. J Obstet Gynaecol Can 2007; 29: S3–56.

53. Thank you for attention