Editing Polyhydramnios

{{short description|Excess of amniotic fluid in the amniotic sac}}
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'''Polyhydramnios''' is a medical condition describing an excess of [[amniotic fluid]] in the [[amniotic sac]]. It is seen in about 1% of pregnancies.<ref>{{cite journal | author = Alexander ES, Spitz HB, Clark RA | year = 1982 | title = Sonography of polyhydramnios | journal = AJR Am J Roentgenol | volume = 138 | issue = 2 | pages = 343–6 | doi = 10.2214/ajr.138.2.343 | pmid = 7034509 }}</ref><ref>{{cite journal | pmid = 3540761 | volume=69 | title=Polyhydramnios: ultrasonically detected prevalence and neonatal outcome | date=January 1987 | author=Hill LM, Breckle R, Thomas ML, Fries JK | journal=Obstet Gynecol | issue=1 | pages=21–5 }}</ref><ref>{{cite journal | pmid = 453266 | volume=134 | title=Ultrasound in the diagnosis of congenital anomalies | date=June 1979 | author=Hobbins JC, Grannum PA, Berkowitz RL, Silverman R, Mahoney MJ | journal=Am. J. Obstet. Gynecol. | issue=3 | pages=331–45 | doi=10.1016/s0002-9378(16)33043-5 }}</ref>  It is typically diagnosed when the [[amniotic fluid index]] (AFI) is greater than 24&nbsp;cm.<ref name="Barnhard">{{cite journal | author = Barnhard Y, Bar-Hava I, Divon MY | date = Nov 1995 | title = Is polyhydramnios in an ultrasonographically normal fetus an indication for genetic evaluation? | journal = Obstet Gynecol | volume = 173 | issue = 5| pages = 1523–7 | doi = 10.1016/0002-9378(95)90643-6 | pmid = 7503195 }}</ref><ref>{{cite journal | author = Brady K, Polzin WJ, Kopelman JN, Read JA | year = 1992 | title = Risk of chromosomal abnormalities in patients with idiopathic polyhydramnios | journal = Obstet Gynecol | volume = 79 | issue = 2 | pages = 234–8 | pmid = 1731291 }}</ref>
There are two clinical varieties of polyhydramnios: chronic polyhydramnios where excess amniotic fluid accumulates gradually, and acute polyhydramnios where excess amniotic fluid collects rapidly.

The opposite to polyhydramnios is [[oligohydramnios]], not enough amniotic fluid.

==Presentation==
===Associated conditions===
Fetuses with polyhydramnios are at risk for a number of other problems including [[cord prolapse]], [[placental abruption]], [[premature birth]] and perinatal death. At delivery the baby should be checked for congenital abnormalities.

==Causes==
[[File:Ultrasound Scan ND 152505 1531230 cr.png|thumb]]
In most cases, the exact cause cannot be identified. A single case may have one or more causes, including intrauterine infection ([[TORCH complex|TORCH]]), [[Rh disease|rh-isoimmunisation]], or [[chorioangioma]] of the placenta. In a multiple gestation pregnancy, the cause of polyhydramnios usually is [[twin-to-twin transfusion syndrome]]. Maternal causes include [[cardiac]] problems, [[kidney]] problems, and maternal [[diabetes mellitus]], which causes fetal [[hyperglycemia]] and resulting [[polyuria]] (fetal urine is a major source of amniotic fluid).

A recent study distinguishes between mild and severe polyhydramnios and showed that [[Apgar score]] of less than 7, perinatal death and structural malformations only occurred in women with severe polyhydramnios.<ref>Bundgaard A, Andersen BR, Rode L, Lebech M, Tabor A, Prevalence of polyhydramnios at a Danish hospital—a population-based study. Acta Obstet Gynecol Scand. 2007; 86(12): 1427–31.</ref> 
In another study, all patients with polyhydramnios, that had a sonographically normal fetus, showed no chromosomal anomalies.<ref name="Barnhard" />

These anomalies include:

*[[gastrointestinal]] abnormalities such as [[esophageal atresia]] and [[duodenal atresia]] (causing inability to swallow amniotic fluid), anencephaly, facial cleft, neck masses, tracheoesophageal fistula, and diaphragmatic hernias. An annular pancreas causing obstruction may also be the cause. 
*Bochdalek's hernia, in which the pleuro-peritoneal membranes (especially the left) will fail to develop and seal the pericardio-peritoneal canals.  This results in the stomach protrusion up into the thoracic cavity, and the fetus is unable to swallow sufficient amounts of amniotic fluid.
* fetal [[renal]] disorders that result in increased urine production during pregnancy, such as in antenatal [[Bartter syndrome]].<ref name="pmid18695706">{{cite journal |author=Seyberth HW. |title=An improved terminology and classification of Bartter-like syndromes. |journal=Nat Clin Pract Nephrol  |volume=4 |issue=10 |pages=560–7 |year=2008 |pmid=18695706 |doi=10.1038/ncpneph0912|s2cid=205340294 }}</ref> Molecular diagnosis is available for these conditions.<ref>{{cite web|url=http://www.moldiag.de/en/dis/bartter.htm |title=Hereditary disease: Bartter syndrome |publisher=Moldiag.de |access-date=2012-09-28}}</ref> 
*neurological abnormalities such as [[anencephaly]], which impair the swallowing reflex. Anencephaly is failure of closure of the rostral neuropore (rostral neural tube defect). If the rostral neuropore fails to close there will be no neural mechanism for swallowing.
*chromosomal abnormalities such as [[Down syndrome]] and [[Edwards syndrome]], which is itself often associated with gastrointestinal abnormalities.
*Skeletal dysplasia, or dwarfism. There is a possibility of the chest cavity not being large enough to house all of the baby's organs causing the trachea and esophagus to be restricted, not allowing the baby to swallow the appropriate amount of amniotic fluid.
*sacrococcygeal [[teratoma]]

==Diagnosis==
There are several pathologic conditions that can predispose a pregnancy to polyhydramnios. These include a maternal history of [[diabetes mellitus]], [[Rh incompatibility]] between the fetus and mother, intrauterine infection, and [[multiple birth|multiple pregnancies]].

During the pregnancy, certain clinical signs may suggest polyhydramnios. In the mother, the physician may observe increased abdominal size out of proportion for her weight gain and gestation age, uterine size that outpaces gestational age, shiny skin with stria (seen mostly in severe polyhydramnios), dyspnea, and chest heaviness. When examining the fetus, faint fetal heart sounds are also an important clinical sign of this condition.

==Treatment==
Mild asymptomatic polyhydramnios is managed expectantly. A woman with symptomatic polyhydramnios may need hospital admission. [[Antacids]] may be prescribed to relieve heartburn and [[nausea]].
No data support dietary restriction of salt and fluid.{{citation needed|date=September 2012}}
In some cases, [[amnioreduction]], also known as therapeutic [[amniocentesis]], has been used in response to polyhydramnios.<ref name="pmid15301292">{{cite journal  |vauthors=Piantelli G, Bedocchi L, Cavicchioni O, etal |title=Amnioreduction for treatment of severe polyhydramnios |series=75 |journal=Acta Biomedica |volume=Suppl 1 |pages=56–8 |year=2004 |pmid=15301292 }}</ref>

== See also ==
*[[Amniotic fluid index]]

==References==
{{reflist}}

==External links==
{{Medical resources
 | DiseasesDB      = 10319 
 | ICD10           = {{ICD10|O|40||o|30}} 
 | ICD9            = {{ICD9|657}} 
 | ICDO            = 
 | OMIM            = 
 | MedlinePlus     = 003267 
 | eMedicineSubj   = radio 
 | eMedicineTopic  = 566 
 | MeshID          = D006831 
}}

* {{Chorus|00329}}

{{Pathology of pregnancy, childbirth and the puerperium}}

[[Category:Pathology of pregnancy, childbirth and the puerperium]]