How much amniotic fluid is there

Cohort studies have shown an association between oligohydramnios and higher rates of labor induction and cesarean section because of non reassuring FHR tracing, 20 as well as adverse perinatal outcome. Indeed, the literature lacks randomized clinical trials to explore whether interventions result in improved perinatal outcome.

Certain fetal anomalies associated or not with genetic conditions are more often associated with severe polyhydramnios; the combination of FGR and polyhydramnios is suggestive of chromosomal aneuploidy ie, Trisomy 18 or These complications increase the risk of cesarean delivery and neonatal intensive care admission.

This observation suggests that diagnosing polyhydramnios based on the AFI is more accurate. Observe fetal movement to rule out neurologic conditions. Obtain peak systolic velocity in the middle cerebral artery to rule out fetal anemia. Examine the placenta with color and power Doppler to rule out placental hemangiomas. If it has not been done, screen for diabetes mellitus, because a linear relationship has been reported between AFI and birth weight centiles in a poorly controlled diabetic population.

If fetal hydrops is detected , request indirect Coombs to rule out an immune etiology as well as maternal testing to rule out congenital infections. Also evaluate for signs of cardiac failure eg, triscuspid regurgitation, pulsations in umbilical vein. If polyhydramnios is associated with other conditions, management is based on the underlying condition.

Monitor fetal well being Because of the above-mentioned associations between polyhydramnios and adverse obstetric outcome, some experts have suggested institution of fetal testing in the presence of polyhydramnios eg, NST weekly until delivery.

Use caution in interpreting the BPP score in the presence of polyhydramnios, since the 2 points for AFV in these cases are not necessarily reassuring. In addition to monitoring fetal well being, measures can be implemented to reduce the amount of amniotic fluid, including amnioreduction Table 7. Before 34 weeks, the procedure can be preceded by prophylactic maternal administration of steroids for fetal lung maturity enhancement in case the procedure results in preterm labor and delivery or triggers placental abruption.

Although fetal lung maturity tests can be assessed at the time of amnioreduction after 34 weeks, their utility is limited because timing of delivery is mostly affected by the coexisting anomalies with possible need for neonatal corrective surgeries and maternal symptoms.

For mild to moderate polyhydramnios with reassuring fetal testing, there is no need to change standard obstetric management. For severe polyhydramnios, care should be taken at the time of membrane rupture to avoid umbilical cord prolapse or abruption.

One solution is to perform an amnioreduction in early labor; alternatively the membranes can be needled to allow gradual spillage of fluid, or can be ruptured at early cervical dilation, because prolapse of a loop of cord is more common as cervical dilation increases. AFV abnormalities-whether diminished or excessive-should prompt an evaluation for underlying causes.

Association and prediction of amniotic fluid measurements for adverse pregnancy outcome: systematic review and meta-analysis. Sonographic estimation of amniotic fluid volume. Subjective assessment versus pocket measurements. J Ultrasound Med. Ultrasound estimate of amniotic fluid volume: color Doppler overdiagnosis of oligohydramnios.

Obstet Gynecol. Amniotic fluid volume estimation and the biophysical profile: a confusion of criteria. At the author's institution, the amniotic fluid volume is initially assessed subjectively. If it is normal, no AFI or largest vertical pocket is measured. However, if the fluid subjectively appears decreased, an AFI is calculated.

The variability in definitions of ultrasound-based oligohydramnios was highlighted in a clinical commentary by Magann and colleagues, which included a plea for future studies that correlate amniotic fluid volume assessment to clinically relevant perinatal outcomes. Indices evaluated included the largest vertical pocket, largest transverse pocket, AFI, largest pocket product vertical x transverse , sum of all pocket measurements, and the sum of the pocket products. They found that the largest vertical pocket, the AFI, and the sum of all pockets were significantly different between the normal and abnormal perinatal outcome groups.

Using receiver operating characteristic curves to establish optimal threshold values, a vertical pocket of 2. Chauhan and colleagues performed a prospective randomized clinical trial comparing the AFI to the largest vertical pocket.

They defined oligohydramnios as either an AFI of 5 cm or less, or the absence of a fluid pocket measuring at least 2 x 1 cm.

The authors concluded that using the AFI increases the number of interventions for oligohydramnios without improving perinatal outcome. They also observed that both techniques of amniotic fluid assessment are poor diagnostic tests for predicting adverse perinatal outcome.

Difficulties arise when comparing various criteria for oligohydramnios. One variable not often addressed in studies is the inclusion or exclusion of fluid pockets that contain loops of umbilical cord.

With oligohydramnios, the umbilical cord makes up an increased proportion of fluid pockets. Some studies excluded any pocket that contained cord, while others measured the dimensions of fluid that surrounded cord.

A frequently overlooked but critically important issue is that of transducer positioning. In some reports, the transducer was held at right angles to the uterine contour, 54 , 58 whereas in others the plane of the ultrasound was perpendicular to the floor or sagittal plane of the abdomen. Orientation is critical in evaluating vertical diameter. If the transducer is held perpendicular to the uterine contour, a view from the lateral aspect of the uterus might falsely create a vertical pocket on the ultrasonography screen.

For the sake of consistency, it is recommended that the transducer be oriented longitudinally and perpendicular to the plane of the floor the plane in which the fluid has layered , thereby minimizing differences if the subject is laterally displaced. The literature suggests that oligohydramnios does increase the risk in a fetus with no major anomalies.

However, the clinical significance of oligohydramnios differs between studies, depending on criteria used and end points evaluated. Overall, decreased amniotic fluid is associated with a higher incidence of SGA infants less than the 10th percentile for gestational age , postmaturity syndrome, variable and late decelerations in labor, cesarean section for nonreassuring fetal heart rate tracing, lower umbilical artery pH, lower Apgar scores, and higher perinatal mortality.

Second-trimester oligohydramnios is especially associated with adverse perinatal outcomes, as a result of both pulmonary hypoplasia and lethal congenital anomalies. The relative degree to which the increased morbidity results from either the underlying condition producing the oligohydramnios or from a direct effect of the reduced fluid i.

However, there is some suggestion that part of the risk of cord compression may be reversible, as indicated by studies in which fluid was removed versus those in which fluid was replaced amnioinfusion to determine clinical effect. Gabbe and colleagues noted that removal of amniotic fluid from the amniotic cavity of fetal monkeys resulted in variable decelerations secondary to cord compression.

In the absence of membrane rupture or fetal urinary obstruction, there is no known direct treatment for antepartum oligohydramnios. Oligohydramnios in the absence of major congenital anomalies may be a marker for prior fetal adjustment to chronic uteroplacental insufficiency or partial cord occlusion, as well as a predisposing factor for cord compression.

Therefore, it is generally recommended that, depending on gestational age, these patients be either followed closely with serial antenatal testing nonstress test, biophysical profile including assessment for the presence of variable decelerations, or else delivered. However, when oligohydramnios is present, there is no consensus at this time about a critical diagnosis-to-delivery interval.

In the presence of marked oligohydramnios at term, delivery should be initiated within 24 to 48 hours after diagnosis, or earlier in the presence of associated findings such as spontaneous variable decelerations. Further study is indicated to determine the benefits of such an approach on both short- and long-term morbidity.

Oligohydramnios resulting from congenital urinary tract obstruction e. Oligohydramnios increases the risk of cord compression during labor; consequently, the fetus should be followed closely for variable decelerations.

Persistent, moderate or severe variable decelerations may be ameliorated with the use of amnioinfusion during labor. Amniotic fluid is the product of complex and dynamic fetal and placental physiologic processes. Disruption of the fine balance may result in overproduction or underproduction of fluid. Both polyhydramnios and oligohydramnios may be associated with either major congenital anomalies or adverse perinatal outcomes.

Although the ultrasonographic diagnostic criteria have yet to be firmly established, it is apparent that both subjective and objective criteria have been used successfully to identify these conditions. Polyhydramnios, particularly when severe and detected early in gestation, can be treated antenatally with serial amniocenteses. Oligohydramnios with intact membranes, especially when severe and in the absence of anomalies, is usually managed by delivery; however, further research is indicated to delineate management guidelines.

Amniotic fluid volume remains an important component of any obstetric ultrasonographic examination. Standardized criteria for the diagnosis of polyhydramnios and oligohydramnios, which may be gestational age dependent, are necessary to improve comparisons between studies and to improve communication among those performing and interpreting sonographic assessments of amniotic fluid volume.

J Obstet Gynaecol Br Commonw , Abramovich DR: Fetal factors influencing the volume and composition of liquor amnii. Bronshtein M, Yoffe N, Brandes JM et al: First and early second-trimester diagnosis of fetal urinary tract anomalies using transvaginal sonography. Prenat Diagn , Am J Obstet Gynecol 15, Br J Obstet Gynaecol , Lancet 1: , Duenhoelter JH, Pritchard JA: Fetal respiration: Quantitative measurements of amniotic fluid inspired near term by human and rhesus fetuses.

Obstet Gynecol 74, Wallenburg HCS: The amniotic fluid. Water and electrolyte homeostasis. J Perinat Med 5: , Gillibrand PN: The rate of water transfer from the amniotic sac with advancing pregnancy. Lancet 2: , Am J Obstet Gynecol 34, Pedersen J: Glucose content of the amniotic fluid in diabetic pregnancies. Acta Endocrinol , Polyhydramnios and oligohydramnios. J Perinat Med 6: , Obstet Gynecol 1: , Cousins L, Benirschke K, Porreco R et al: Placentomegaly due to fetal congestive failure in a pregnancy with a sacrococcygeal teratoma.

J Reprod Med , The relationship of increased amniotic fluid volume to perinatal outcome. Bottoms SF, Welch RA, Zador IE et al: Limitations of using maximum vertical pocket and other sonographic evaluations of amniotic fluid volume to predict fetal growth: Technical or physiologic? Int J Gynecol Obstet , Pitkin RM: Acute polyhydramnios recurrent in successive pregnancies.

Obstet Gynecol 42S, Cabrol D, Landesman R, Muller J et al: Treatment of polyhydramnios with prostaglandin synthetase inhibitor indomethacin. Need help? Frequently asked questions Contact us.

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You've saved this page It's been added to your dashboard. In This Topic. How does amniotic fluid keep your baby healthy? How much amniotic fluid should there be? Anytime during your pregnancy, drinking a lot of water can make a huge difference. According to one study , hydration is very helpful for upping amniotic fluid levels in women between 37 and 41 weeks of pregnancy. While more research is needed, a Cochrane database review also found that simple hydration increased amniotic fluid levels.

The nice thing about this remedy? An amnioinfusion is when your doctor squirts a saltwater solution saline through your cervix and into the amniotic sac. This can at least temporarily increase the level of amniotic fluid.

Amniocentesis involves a thin needle being inserted directly into the amniotic sac through your abdomen. If you have low amniotic fluid before or during labor, your doctor may give you fluid via amniocentesis before delivering your baby. This can help your baby maintain their mobility and heart rate throughout the delivery, which may also help decrease your chances of a cesarean delivery.

Your doctor may recommend IV fluids. Since low amniotic fluid may be caused by underlying conditions such as high blood pressure or diabetes, treating these conditions may improve your levels. This may involve taking medication, monitoring your blood sugar, or making more frequent visits to your doctor.

Preexisting causes may create other issues during your pregnancy, too, so managing the cause is a win-win. But some doctors will still prescribe it in the case of low amniotic fluid. Resting in bed or on the couch except to go to the bathroom or shower may help improve blood flow to the placenta, which in turn helps increase amniotic fluid. Find that perfect Netflix show to binge on and let those around you wait on you hand and foot.

This may sound scary, but there are a couple of bonuses to extra monitoring: One, you get to see your baby more often! And two, your doctor will be able to treat any issues sooner than later.

Some research — only in animals, though — shows a modest negative effect on amniotic fluid levels when mom consumes a high fat diet. Fancy being on the safe side?