AFV`s transabdominal ultrasound includes the use of the maximum vertical pocket (MVP) or amniotic fluid index (AFI), depending on the facility. The sonographer systematically scans the abdomen and gets an image showing the maximum vertical pouch – the deepest pocket of amniotic fluid that does not contain fetal umbilical cord or body parts. The measurement must be carried out from the 12 o`clock position to the 6 o`clock position. The normal range for MVP is 2 to 8 cm: A 8 is considered polyhydramnios. The Amniotic Fluid Index (AFI) is an alternative assessment of AFV. AFI can be determined at 20 weeks of pregnancy by dividing the uterus into four quadrants by the navel and determining the MVP in each quadrant. The sum of the four maximum vertical pockets is equal to the AFI. An AFI <5cm is compatible with oligohydramnios. [5] The development of oligohydramnios may be idiopathic or have a maternal, fetal or placental cause. [4] If you have signs of low amniotic fluid, your doctor will measure the amount of amniotic fluid in your uterus with an ultrasound. If the amount of fluid is less than the recommended amount for the gestational age of your fetus, you may have oligohydramnios. The care and treatment of patients with amniotic fluid diseases relies on interprofessional communication between multiple providers to ensure appropriate screening, diagnosis and management of these diseases during the antepartum, partial and postpartum periods. Clinically trained obstetricians or midwives often detect oligohydramnios during routine antenatal care visits.
Oligohydramnios is a disease of the amniotic fluid that causes a reduction in the volume of amniotic fluid at gestational age. Low volumes of amniotic fluid can be the result of many maternal, fetal or placental complications and lead to poor fetal outcomes. This activity will shed light on the pathophysiology, etiology, evaluation and treatment of oligohydramnios and will also explore the role of health teams in the assessment and treatment of this disease. After the initial diagnosis of oligohydramnios, the next step is to take a thorough medical history and physical examination, followed by diagnostic tests, if indicated. [2] There are several causes of oligohydramnios. Generally, it is caused by conditions that prevent or reduce the production of amniotic fluid. Factors associated with oligohydramnios include: Low levels of amniotic fluid or oligohydramnios are a potentially serious condition. This can lead to complications during your pregnancy and impair your baby`s growth. However, try to stay calm – most people diagnosed with low amniotic fluid levels have healthy babies. Your doctor will monitor you closely and work with you to determine the safest treatment plan. Attending all prenatal visits and sharing your pregnancy symptoms is the best way to identify potential problems.
Maybe. Some studies show that drinking water can help increase amniotic fluid levels in pregnant women. Talk to your doctor about increasing your water intake to treat oligohydramnios. Although there is some controversy about the timing of delivery in isolated oligohydramnios, current recommendations support delivery at 37 weeks` gestation, provided the membranes remain intact. [11] Idiopathic, uncomplicated and persistent oligohydramnios may be administered at 36 0/7 weeks – 37 6/7 weeks of pregnancy or at diagnosis if diagnosed later. [1] Fetal genitourinary abnormalities can therefore lead to the diagnosis of oligohydramnios after the 16th to 20th week of pregnancy. Examples include obstruction of the bladder outlet, dysplastic kidneys and renal agenesis. Fetal swallowing and intramembranous absorption, which is believed to occur by osmotic absorption of fluid directly through the amnion and into fetal blood vessels, are the main routes of amniotic absorption. Therefore, fetal gastrointestinal abnormalities, such as tracheoesophageal fistula (incidence rate of about 1 in 3500 live births), can lead to excessive fluid volume or polyhydramnios.
[4] Oligohydramnios is a medical condition during pregnancy characterized by a lack of amniotic fluid, the fluid that surrounds the fetus in the abdomen, in the amniotic sac. It is usually diagnosed by ultrasound when the amniotic fluid index (AFI) is less than 5 cm or when the smallest deepest pouch (SDP) of amniotic fluid is less than 2 cm. [1] Amniotic fluid is necessary to allow normal fetal movement, lung development, and attenuation by uterine compression. [2] Low amniotic fluid levels can be attributed to a maternal, fetal, placental or idiopathic cause and can lead to poor fetal outcomes, including death. The prognosis of the fetus depends on the etiology, gestational age at diagnosis and severity of oligohydramnios. In addition to treating the underlying cause, antenatal management includes maximum weekly measurements of vertical pockets and non-stress tests, which have been shown to reduce the occurrence of unexplained fetal death. Fetal growth should be evaluated in series. Maternal hydration status also plays an important role in treatment, especially with oligohydramnios isolated in the third trimester. [10] “As your pregnancy develops, the amount of amniotic fluid changes,” says Dr. Anita Sabharwal Anand, a well-known gynecologist at Sitaram Bhartia Hospital, south of Delhi| “If this fluid is lower after a quarter of the woman, then this condition becomes oligohydramnios (oligohydramnios meaning| The use of the maximum vertical bag tends to overdiagnose cases of polyhydramnios, while the use of AFI tends to underdiagnose cases of oligohydramnios. With this in mind, some institutions choose to use MVP in pregnancies with low AFV and use AFI in cases of high AFV.
MVP should be used to assess oligohydramnios in multifetal pregnancies as you cannot measure all four quadrants for each fetus. [3] [2] In oligohydramnios diagnosed in the second trimester, pulmonary hypoplasia is the most significant predictor of fetal mortality. The mortality rate of oligohydramnios in the second trimester can be as high as 90%, with pulmonary hypoplasia accounting for 87% of these deaths. The most severe pulmonary hypoplasia occurs with oligohydramnios before or during the gestational age of 16 to 24 weeks, when the terminal sacs of the fetal lung develop. Low AFV in the second and early third trimester also increases the likelihood of limb contractures and birth defects due to compression of the fetal parts. [12] If you are diagnosed with oligohydramnios in the last trimester (weeks 28 to 40) of pregnancy, complications may be: The use of oligohydramnios as a predictor of pregnancy complications is controversial. [9] [10] Potter`s syndrome is a condition caused by oligohydramnios. Affected fetuses develop pulmonary hypoplasia, limb deformities and characteristic faces. Bilateral agenesis of the fetal kidneys is the most common cause due to lack of fetal urine. After diagnosis, it is often necessary to consult with maternal-fetal medicine specialists and neonatologists who can help develop an optimal care plan to limit the risk of complications for both the mother and the fetus. Care plans include antepartum management, timing of delivery, and postpartum care, each targeting the underlying etiology of oligohydramnios. [13] Treatment and prognosis for oligohydramnios vary considerably depending on the underlying etiology, gestational age at diagnosis, and severity of oligohydramnios.
Diagnosis of oligohydramnios in the second trimester is more likely to be associated with fetal or maternal abnormalities, while diagnosis in the third trimester is more likely to be of unexplained origin. In one study, the etiology of oligohydramnios was unexplained in only 4% of pregnancies in the second trimester, while 52% of patients diagnosed in the third trimester were idiopathic. Only 10.2 percent of fetuses diagnosed in the second trimester survived, while the survival rate of fetuses diagnosed in the third trimester was 85.3 percent. [12] Low levels of amniotic fluid, also called oligohydramnios, are a serious condition. This happens when the amount of amniotic fluid is less than expected for a baby`s gestational age. There is no treatment that can completely correct this condition. But short-term treatment options are available and may be helpful in some situations. Oligohydramnios complicates 4.4% of all pregnancies during downtime. The incidence of oligohydramnios is less than 1% in early pregnancy. [7] One to two liters of oral hydration may temporarily increase amniotic fluid in dehydrated patients with isolated oligohydramnios.
[6] The diagnosis of oligohydramnios is made by performing a transabdominal ultrasound of the abdomen.
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