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Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from mechanical trauma Bacteriostatic Development of both the lungs and the limbs. Fetal diagnosis Volume 10 mL at 8 weeks 630 mL at 22 weeks 770 mL at 28 weeks After 30 weeks, the increase slows 515 mL at 41 weeks Amniotic fluid volume (mL) Gestational age (weeks) 0 500 1000 1500 2000 2500 8 12 16 20 24 28 32 36 40 44 1% 5% 25% 50% 75% 95% 99%
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Page 1: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Amniotic fluid and cord prolapse

Dr. Wajeih ALAali, SSCOG, ABOG, MFMConsultant OBGYN and Fetal medicine

Amniotic fluid

❖ Protects the fetus from mechanical trauma

❖ Bacteriostatic

❖ Development of both the lungs and the limbs.

❖ Fetal diagnosis

Volume

❖ 10 mL at 8 weeks

❖ 630 mL at 22 weeks

❖ 770 mL at 28 weeks

❖ After 30 weeks, the increase slows

❖ 515 mL at 41 weeks

48 PART 1 Scientific Basis of Perinatal Biology

mechanisms act to maintain AF volume, and there is some evidence that they may be regulated to normalize AF volume in pathologic conditions.

The major contributors to AF volume in the latter portion of pregnancy are fetal urine and fluid produced by the fetal lung. Minor contributors are transudation across the umbilical cord and skin and water produced as a result of fetal metabo-lism. Although some data on these processes in the human fetus are available, the bulk of the information about fetal AF circula-tion derives from animal models, primarily the sheep.

URINE PRODUCTION

Although the mesonephros can produce urine by 5 weeks of gestation, the metanephros (the adult kidney) develops later, with nephrons formed at 9 to 11 weeks,20 at which time fetal urine is excreted into the AF. The amount of urine produced increases progressively with advancing gestation, and it consti-tutes a significant proportion of the AF in the second half of pregnancy.21 The amount of urine produced by the human fetus has been estimated by the use of ultrasound assessment of fetal bladder volume.22 Although there continues to be uncertainty regarding the accuracy of noninvasive measurements, human fetal urine output appears to increase from 110 mL/kg/24 hr at 25 weeks to almost 200 mL/kg/24 hr at term,22,23 in the range of 25% of body weight per day or almost 1000 mL/day near term.22,24-26 In near-term fetal sheep, with direct methods used for measuring urine production rates, similar high values have been found.27-29 There may be a tendency for the urine flow rate to decrease after 40 weeks’ gestation, particularly if oligohy-dramnios is present.30

Reduction or absence of fetal urine flow is commonly associ-ated with oligohydramnios, indicating that urine flow is

latter half of pregnancy, most commonly in the sheep model. Evidence suggests that the entire volume of AF turns over on a daily basis,18 making this a highly dynamic system. The volume of AF is influenced by a complex interplay of productive and absorptive mechanisms (Fig. 3-2).19 These

Figure 3-1 Amniotic fluid volumes from 8 to 44 weeks of human gestation. Dots repre-sent mean measurements for each 2-week interval. Shaded area indicates the 95% confi-dence interval (2.5 to 97.5 percentiles). (From Brace RA, Wolf EJ: Normal amniotic fluid volume changes throughout pregnancy, Am J Obstet Gynecol 161:382–388, 1989.)

Am

niot

ic fl

uid

volu

me

(mL)

Gestational age (weeks)

0

500

1000

1500

2000

2500

8 12 16 20 24 28 32 36 40 44

1%5%25%50%

75%

95%

99%

Figure 3-2 Circulation of amniotic fluid water to and from the fetus. (Modified from Seeds AE: Current concepts of amniotic fluid dynamics, Am J Obstet Gynecol 138:575, 1980.)

Lung fluid

Swallowing

Urine

Intramembranouspathway

Amnion

Chorionlaeve

Placenta

Amniotic fluid

Page 2: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Composition of Amniotic Fluid

❖ First trimester: isotonic with maternal or fetal plasma minimal protein components. extremely low oxygen tension and an increased concentration of sugar alcohols

❖ Second half of pregnancy: urea, creatinine, and uric acid increase

Production of Amniotic Fluid ❖ Early pregnancy:

✓ nonkeratinized fetal skin

✓ From the mother across the uterine decidua or the placenta surface

❖ Second half of pregnancy

✓ Urine production

✓ Fetal lung fluid

48 PART 1 Scientific Basis of Perinatal Biology

mechanisms act to maintain AF volume, and there is some evidence that they may be regulated to normalize AF volume in pathologic conditions.

The major contributors to AF volume in the latter portion of pregnancy are fetal urine and fluid produced by the fetal lung. Minor contributors are transudation across the umbilical cord and skin and water produced as a result of fetal metabo-lism. Although some data on these processes in the human fetus are available, the bulk of the information about fetal AF circula-tion derives from animal models, primarily the sheep.

URINE PRODUCTION

Although the mesonephros can produce urine by 5 weeks of gestation, the metanephros (the adult kidney) develops later, with nephrons formed at 9 to 11 weeks,20 at which time fetal urine is excreted into the AF. The amount of urine produced increases progressively with advancing gestation, and it consti-tutes a significant proportion of the AF in the second half of pregnancy.21 The amount of urine produced by the human fetus has been estimated by the use of ultrasound assessment of fetal bladder volume.22 Although there continues to be uncertainty regarding the accuracy of noninvasive measurements, human fetal urine output appears to increase from 110 mL/kg/24 hr at 25 weeks to almost 200 mL/kg/24 hr at term,22,23 in the range of 25% of body weight per day or almost 1000 mL/day near term.22,24-26 In near-term fetal sheep, with direct methods used for measuring urine production rates, similar high values have been found.27-29 There may be a tendency for the urine flow rate to decrease after 40 weeks’ gestation, particularly if oligohy-dramnios is present.30

Reduction or absence of fetal urine flow is commonly associ-ated with oligohydramnios, indicating that urine flow is

latter half of pregnancy, most commonly in the sheep model. Evidence suggests that the entire volume of AF turns over on a daily basis,18 making this a highly dynamic system. The volume of AF is influenced by a complex interplay of productive and absorptive mechanisms (Fig. 3-2).19 These

Figure 3-1 Amniotic fluid volumes from 8 to 44 weeks of human gestation. Dots repre-sent mean measurements for each 2-week interval. Shaded area indicates the 95% confi-dence interval (2.5 to 97.5 percentiles). (From Brace RA, Wolf EJ: Normal amniotic fluid volume changes throughout pregnancy, Am J Obstet Gynecol 161:382–388, 1989.)

Am

niot

ic fl

uid

volu

me

(mL)

Gestational age (weeks)

0

500

1000

1500

2000

2500

8 12 16 20 24 28 32 36 40 44

1%5%25%50%

75%

95%

99%

Figure 3-2 Circulation of amniotic fluid water to and from the fetus. (Modified from Seeds AE: Current concepts of amniotic fluid dynamics, Am J Obstet Gynecol 138:575, 1980.)

Lung fluid

Swallowing

Urine

Intramembranouspathway

Amnion

Chorionlaeve

Placenta

Amniotic fluid

Amniotic fluid abnormality

❖ Polyhydraqmnios: Amniotic fluid index (AFI) > 24 cm or a single pocket of fluid at least 8 cm in depth that results in an amniotic fluid volume of more than 2000 mL

❖ Oligohydramnios: AFI < 7 cm or the absence of a fluid pocket 2-3 cm in depth.

Page 3: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Polyhydramnios Causes:

❖ Poorly controlled maternal diabetes mellitus

❖ Fetal anomalies: CNS abnormalities and neuromuscular diseases

❖ Congenital cardiac-rhythm anomalies , hydrops

❖ twin-to-twin transfusion syndrome

❖ Fetal infection- TORCH

❖ Chromosomal abnormalities

❖ Fetal akinesia syndrome

❖ Idiopathic

Polyhydramnios Laboratory Workup:

❖ OGTT

❖ Kleihauer-Betke test to evaluate fetal-maternal hemorrhage

❖ Hemoglobin Bart in patients of Asian descent (who may be heterozygous for alpha-thalassemia)

❖ Fetal karyotyping for trisomy 21, 13, and 18

❖ TORCH

❖ Blood group and antibody assessment

Polyhydramnios Ultrasound Workup:

❖ Evaluate the fetal anatomy; assess for diaphragmatic hernia, lung masses, and the absence of the stomach bubble. The double-bubble sign!

❖ A macrosomic fetus is observed in association with poorly controlled maternal diabetes.

❖ Assess the blood flow velocity in the middle cerebral artery of the fetus for fetal anemia.

❖ Test for fetal arrhythmias and malformations

❖ Large abdominal circumference may be observed with ascites and hydrops fetalis.

Polyhydramnios

Medical care:

❖ Higher incidence of preterm labor secondary to overdistention of the uterus.

❖ Weekly or twice weekly perinatal visits and cervical examinations.

❖ Bed rest to decrease the likelihood of preterm labor.

❖ Serial ultrasonography to determine the AFI and document fetal growth.

❖ Fetal anemia

Page 4: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Oligohydramnios

Oligohydramnios Causes:

❖ PROM and chronic leakage of the amniotic fluid

❖ Fetal urinary tract anomalies, such as renal agenesis, polycystic kidneys, or any urinary obstructive lesion

❖ Placental insufficiency, as seen in pregnancy-induced hypertension (PIH), maternal diabetes, or postmaturity syndrome

❖ Maternal use of prostaglandin synthase inhibitors or ACE inhibitors

Oligohydramnios

Laboratory Workup:

❖ Nitrazine test

❖ Ferning test

❖ PAMG-1 test

❖ placental insufficiency tests

Oligohydramnios Ultrasound Workup:

❖ Visualize the fetal kidneys, collecting system, and bladder. If these are normal, suspect the chronic leakage of amniotic fluid or hypertensive disorders.

❖ Assess fetal growth. If PROM or urinary tract anomalies are absent, consider placental insufficiency and IUGR.

❖ Uterine artery Doppler study findings may aid in the diagnosis of placental insufficiency.

Page 5: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Cord prolapse

Cord prolapse

❖ The cord lies in front of the presenting part and the fetal membranes are ruptured

❖ umbilical cord passes through the cervix at the same time as or in advance of the fetal presenting part.

Cord prolapse

❖ Occult: cord passes through the cervix alongside the fetal presenting part; it is neither visible nor palpable.

❖ Overt: cord presents in advance of the fetus and is visible or palpable within the vaginal vault or even past the labia.

Page 6: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Risk factors

9/8/16, 10:25 PMUmbilical cord prolapse | Contemporary OB/GYN

Page 2 of 9http://contemporaryobgyn.modernmedicine.com/contemporary-obgyn/content/tags/bradley-holbrook-md/umbilical-cord-prolapse?page=full

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UCP can be occult or overt. Occult prolapse occurs when the cord passes through the

cervix alongside the fetal presenting part; it is neither visible nor palpable. In overt

prolapse, the cord presents in advance of the fetus and is visible or palpable within the

vaginal vault or even past the labia.

Prolapse of the cord often leads to cord compression which, in turn, leads to abnormal

findings on fetal heart rate (FHR) tracings in 41% to 67% of cases. These changes may

present as a severe, sudden deceleration, often with prolonged bradycardia, or recurrent

moderate-to-severe variable decelerations. The diagnosis of overt UCP is made on vaginal

examination, which will reveal a palpable umbilical cord (usually a soft, pulsating mass)

within or visibly extruding from the vagina. A confirmed diagnosis of occult UCP is rare,

because it cannot be definitively diagnosed even when Doppler ultrasound imaging is

employed. Attempts to identify occult prolapse with imaging could delay necessary

treatment for this emergent condition. Occult UCP likely is the cause of some cases of

urgent cesarean delivery for unexplained fetal bradycardia.

NEXT: RISK FACTORS >>NEXT: RISK FACTORS >>

Risk factorsRisk factors

Several factors increase the risk of cord prolapse. The main precipitating event is rupture of

membranes (ROM), either spontaneous or performed artificially by a healthcare provider.

Most risk factors for UCP can be separated into two categories: spontaneous and

iatrogenic (Table 1).

Spontaneous causes may be related to fetal factors, uterine distention, or pregnancy

complications. Fetal risk factors include malpresentation, fetal anomalies, fetal growth

restriction/small for gestational age, funic presentation, and cord abnormalities. Factors

related to uterine distention include polyhydramnios, multiple gestation (although this may

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HOME PUBLICATIONS BUSINESS EDUCATION CAREERS CONTACT US LOG IN | REGISTER Prevention

❖ Avoid amniotomy unless the fetal head is well-engaged

Diagnosis

❖ Fetal heart rate abnormalities

❖ Visual of prolapsed cord

Management

❖ It is a top emergency

❖ NEEDS URGENT DELIVERY

❖ However, Lethal anomaly, demised foetus.

Page 7: AF and cord prolapse - Wikispacesand...Amniotic fluid and cord prolapse Dr. Wajeih ALAali, SSCOG, ABOG, MFM Consultant OBGYN and Fetal medicine Amniotic fluid Protects the fetus from

Management

9/8/16, 10:25 PMUmbilical cord prolapse | Contemporary OB/GYN

Page 4 of 9http://contemporaryobgyn.modernmedicine.com/contemporary-obgyn/content/tags/bradley-holbrook-md/umbilical-cord-prolapse?page=full

Elevation of the presenting fetal part. The key first step after identifying a UCP is to elevate

the presenting fetal part off the prolapsed cord. This is generally performed manually, with

the physician placing 2 fingers or an entire hand into the vagina to elevate the fetus off the

cord. Care should be taken to avoid palpation of the cord because that may cause

vasospasm, potentially leading to a worse outcome. Placing the patient in steep

Trendelenburg or in knee-chest position is believed to be helpful by taking advantage of

gravity to further relieve pressure on the cord.

In cases in which the interval to delivery is likely to be prolonged (that is, requiring maternal

transport to a facility where cesarean delivery can be performed), bladder filling may be a

better option. With this technique—commonly called Vago’s method, in reference to the

physician who first described the technique—a Foley catheter is placed and the bladder is

filled with 500 to 750 mL of saline, and then clamped. The patient’s enlarging bladder

provides upward pressure on the fetus, thus alleviating the compression on the cord. Vago

described this as an alternative to manual elevation, which he described as “effective, but .

. . unpleasant for the mother and wearying for the doctor.” He also noted that in his

experience, filling the bladder tends to calm uterine contractions, which would certainly

further relieve pressure on the cord. Over the years, studies have shown Vago’s method to

be effective. To employ this strategy requires that a cord prolapse tray be immediately

available (Figure 1). Comparison of manual elevation of the presenting part versus bladder

filling shows essentially equal outcomes between the 2 groups. It should be noted that

the combination of the 2 methods does not lead to any improvement over using either

alone.

2

9

10

10,11

12

Management

Management9/8/16, 10:25 PMUmbilical cord prolapse | Contemporary OB/GYN

Page 7 of 9http://contemporaryobgyn.modernmedicine.com/contemporary-obgyn/content/tags/bradley-holbrook-md/umbilical-cord-prolapse?page=full

ReferencesReferences

1. Kahana B, Sheiner E, Levy A, et al. Umbilical cord prolapse and perinatal outcomes. Int J GynaecolObstet. 2004;84:127–132.

2. Lin MG. Umbilical cord prolapse. Obstet Gynecol Surv. 2006;61:269–277.

3. Koonings PP, Paul RH, Campbell K. Umbilical cord prolapse. A contemporary look. J Reprod Med.

1990;35:690–692.

4. Boyle JJ, Katz VL. Umbilical cord prolapse in current obstetric practice. J Reprod Med. 2005;50:303–306.

5. Murphy DJ, MacKenzie IZ. The mortality and morbidity associated with umbilical cord prolapse. Br JObstet Gynaecol. 1995;102:826–830.

6. Usta IM, Mercer BM, Sibai BM. Current obstetrical practice and umbilical cord prolapse. Am J Perinatol.1999;16:479–484.

7. Holbrook BD, Phelan ST. Umbilical cord prolapse. Obstet Gynecol Clin North Am. 2013;40:1–14.

8. Critchlow CW, Leet TL, Benedetti TJ, Daling JR. Risk factors and infant outcomes associated with

umbilical cord prolapse: a population-based case-control study among births in Washington State. Am JObstet Gynecol. 1994;170:613–618.

9. Katz Z, Lancet M, Borenstein R. Management of labor with umbilical cord prolapse. Am J ObstetGynecol. 1982;142:239–241.

10. Vago T. Prolapse of the umbilical cord: a method of management. Am J Obstet Gynecol. 1970;107:967–

969.

11. Caspi E, Lotan Y, Schrever Pl. Prolapse of the cord: reduction of perinatal mortality by bladder instillation

and cesarean section. Isr J Med Sci. 1983;19:541–545.

12. Bord I, Gemer O, Anteby EY, Shenhav S. The value of bladder filling in addition to manual elevation of

presenting fetal part in cases of cord prolapse. Arch Gynecol Obstet. 2011;283:989–991.

13. Barrett JM. Funic reduction for the management of umbilical cord prolapse. Am J Obstet Gynecol.1991;165:654–657.

14. Leong A, Rao J, Opie G, Dobson P. Fetal survival after conservative management of cord prolapse for

three weeks. BJOG. 2004;111:1476–1477.

15. Siassakos D, Hasafa Z, Sibanda T, et al. Retrospective cohort study of diagnosis-delivery interval with

umbilical cord prolapse: the effect of team training. BJOG. 2009;116:1089–1096.

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