Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the
amnionof a pregnant woman.
The amnion grows and begins to fill, mainly with water, around two weeks after
fertilization. After a further 10 weeks the liquid contains proteins, carbohydrates, lipids and phospholipids, ureaand electrolytes, all which aid in the growth of the fetus. In the late stages of gestation much of the amniotic fluid consists of fetal urine.
The amniotic fluid increases in volume as the fetus grows. The amount of amniotic fluid is greatest at about 34 weeks after conception or 34 weeks ga (gestational age). At 34 weeks ga, the amount of amniotic fluid is about 800 ml. This amount reduces to about 600 ml at 40 weeks ga when the baby is born.
Amniotic fluid is continually being swallowed and "inhaled" and replaced through being "exhaled", as well as being urinated by the baby. It is essential that the amniotic fluid be breathed into the lungs by the fetus in order for the lungs to develop normally. Swallowed aminotic fluid contributes to the formation of
Analysis of amniotic fluid, drawn out of the mother's abdomen in an
amniocentesisprocedure, can reveal many aspects of the baby's genetic health. This is because the fluid also contains fetal cells which can be examined for genetic defects. Recent research by researchers led by Anthony Atalaof Wake Forest Universityand a team from Harvard Universityhas found that amniotic fluid is also a plentiful source of non-embryonic stem cells. [cite web |url=http://www.nature.com/nbt/journal/v25/n1/abs/nbt1274.html |title=Isolation of amniotic stem cell lines with potential for therapy : Abstract : Nature Biotechnology |accessdate=2007-10-13 |format= |work=] These cells have demonstrated the ability to differentiate into a number of different cell-types, including brain, liver and bone.
Amniotic fluid also protects the developing baby by cushioning against blows to the mother's abdomen, allows for easier fetal movement, promotes muscular/skeletal development, and helps protect the fetus from heat loss.
The forewaters are released when the amnion ruptures, commonly known as when a woman's "water breaks". When this occurs during labour at term, it is known as "spontaneous rupture of membranes" (SROM). If the rupture precedes labour at term, however, it is referred to as "premature rupture of membranes" (PROM). The majority of the hindwaters remain inside the womb until the baby is born. [ [http://www.babyworld.co.uk/faq/individualfaq.asp?Section=Pregnancy&SubSection=Your+body&query=&opt=&page=&question=1711 Forewaters and hindwaters in Q&A section at babyworld.co.uk] ]
Complications related to amniotic fluid
Too little amniotic fluid (
oligohydramnios) or too much ( polyhydramniosor hydramnios) can be a cause or an indicator of problems for the mother and baby. In both cases the majority of pregnancies proceed normally and the baby is born healthy but this isn't always the case. Babies with too little amniotic fluid can develop contractures of the limbs, clubbing of the feet and hands, and also develop a life threatening condition called hypoplastic lungs. If a baby is born with hypoplastic lungs, which are small underdeveloped lungs, this condition is potentially fatal and the baby can die shortly after birth.
On every prenatal visit, the obstetrician/gynaecologist or midwife should measure the patient's
fundal heightwith a tape measure. It is important that the fundal height be measured and properly recorded to insure proper fetal growth and the increasing development of amniotic fluid. The obstetrician/gynaecologist should also routinely ultrasound the patient—this procedure will also give an indication of proper fetal growth and amniotic fluid development. Oligohydramnios can be caused by infection, kidney dysfunction or malformation (since much of the late amniotic fluid volume is urine), procedures such as chorionic villus sampling(CVS), and preterm premature rupture of membranes (PPROM).
Oligohydramnios can sometimes be treated with
bed rest, oral and intravenous hydration, antibiotics, steroids, and amnioinfusion. Polyhydramniosis a predisposing risk factor for cord prolapseand is sometimes a side effect of a macrosomic pregnancy. Hydramnios is associated with esophageal atresia. Amniotic fluid is primarily produced by the mother until 16 weeks of gestation.
Preterm premature rupture of membranes (PPROM) is a condition where the amniotic sac leaks fluid before 38 weeks of gestation. This can be caused by a bacterial infection or by a defect in the structure of the amniotic sac, uterus, or cervix. In some cases, the leak can spontaneously heal, but in most cases of PPROM, labor begins within 48 hours of membrane rupture. When this occurs, it is necessary that the mother receive treatment to avoid possible infection in the newborn.
Color of the amniotic fluid, with possible meanings:
* GREEN - neco state
* YELLOW - hemolitic disease
* BROWN - infection
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Look at other dictionaries:
amniotic fluid — ► NOUN ▪ the fluid surrounding a fetus within the amnion … English terms dictionary
Amniotic fluid — The fluid bathing the fetus and serving as a shock absorber. * * * amniotic fluid n the serous fluid in which the embryo and fetus is suspended within the amnion * * * the fluid contained within the amniotic cavity. It surrounds the growing fetus … Medical dictionary
amniotic fluid — the fluid contained within the amniotic cavity. It surrounds the growing fetus, protecting it from external pressure. The fluid is initially secreted from the amnion and is later supplemented by urine from the fetal kidneys. Some of the fluid is… … The new mediacal dictionary
amniotic fluid — noun the serous fluid in which the embryo is suspended inside the amnion before a woman gives birth her waters break • Syn: ↑amnionic fluid, ↑waters • Hypernyms: ↑liquid body substance, ↑bodily fluid, ↑body fluid, ↑ … Useful english dictionary
amniotic fluid — Liquid contents of the amniotic sac of higher vertebrates, containing foetal, but not maternal cells … Glossary of Biotechnology
amniotic fluid — noun Date: circa 1855 the serous fluid in which the embryo or fetus is suspended within the amnion … New Collegiate Dictionary
amniotic fluid — Anat., Zool. the watery fluid in the amnion, in which the embryo is suspended. * * * … Universalium
amniotic fluid — noun In placental mammals, a fluid contained within the amnion membrane that surrounds a developing embryo or fetus … Wiktionary
amniotic fluid — noun the fluid surrounding a fetus within the amnion … English new terms dictionary
amniotic fluid — UK [ˌæmnɪɒtɪk ˈfluːɪd] / US [ˌæmnɪɑtɪk ˈfluɪd] noun [uncountable] biology the liquid that a baby lives in inside its mother s womb … English dictionary