How much amniotic fluid is normal at 30 weeks

Researchers need further evidence to know if increasing amniotic fluid in this way improves the health of the fetus. A study examined the use of L-arginine supplementation to treat oligohydramnios when amniotic fluid levels are very low. In the study, pregnant women with a diagnosis of oligohydramnios took 3-gram sachets of L-arginine, three times a day until an increase in amniotic fluid levels occurred.

The study concluded that L-arginine may help treat oligohydramnios by increasing amniotic fluid levels. The benefits include lengthening the pregnancy duration and decreasing the risk of complications.

A doctor may advise more bed rest and decreasing physical activity for women with low amniotic fluid levels. For this treatment, the doctor will introduce a saline solution via the cervix into the amniotic sac to increase fluid levels.

If amniotic fluid drops too low during the final stages of pregnancy, doctors may suggest early labor. Bringing labor forward can help to prevent any potential complications during delivery.

While oligohydramnios occurs when a woman has very low levels of amniotic fluid, polyhydramnios is when the fluid levels are extremely high. Oligohydramnios is a condition where a pregnant woman has too little amniotic fluid. Symptoms and signs of oligohydramnios include:.

Oligohydramnios is most common in the last 3 months of pregnancy, known as the third trimester. Polyhydramnios , or hydramnios, is when levels of amniotic fluid are too high. Hydramnios happens if there are problems with amniotic fluid leaving the body, or if the body is creating too much of it. Untreated polyhydramnios can cause complications for the pregnant woman and the developing fetus.

These complications can include early labor or congenital disabilities. A doctor will take a medical history to check for any preexisting conditions and carry out a physical examination. A doctor will use ultrasounds and measure amounts of amniotic fluid to check levels. Once a doctor has checked levels and found any possible causes, they can decide on the best treatment options. If a pregnant woman has low levels of amniotic fluid towards the end of a healthy pregnancy, they may not need any treatment.

A doctor may just carry out additional monitoring to keep a closer eye on levels, including more frequent ultrasounds. If a pregnant woman has a lower level of amniotic fluid than usual, they or their healthcare team can remedy this. Drinking more water is a simple way of increasing amniotic fluid while resting and decreasing physical exercise may also help. In other cases, an individual may need medical treatment. It is contained in the amniotic sac.

While in the womb, the baby floats in the amniotic fluid. The amount of amniotic fluid is greatest at about 34 weeks gestation into the pregnancy, when it averages mL. About mL of amniotic fluid surrounds the baby at full term 40 weeks gestation.

The amniotic fluid constantly moves circulates as the baby swallows and "inhales" the fluid, and then releases it. Too much amniotic fluid is called polyhydramnios.

This condition can occur with multiple pregnancies twins or triplets , congenital anomalies problems that exist when the baby is born , or gestational diabetes. Too little amniotic fluid is known as oligohydramnios. AFI is calculated by summing the depth in centimeters of 4 different pockets of fluid not containing cord or fetal extremities in 4 abdominal quadrants using the umbilicus as a reference point and with the transducer perpendicular to the floor. SDP refers to the vertical dimension of the largest pocket of amniotic fluid with a horizontal measure of at least 1 cm not containing umbilical cord or fetal extremities and measured at a right angle to the uterine contour and perpendicular to the floor.

Ultrasound estimates of AFV correlate poorly with direct measurements of amniotic fluid. The use of percentiles rather than fixed cut-offs does not improve the accuracy of AFI in identification of low or high AFV. A review comparing AFI and SDP has found that use of AFI results in overdiagnosis of oligohydramnios, leading to unnecessary interventions eg, labor induction , which often contribute to increased morbidity without an improvement in perinatal outcomes.

To improve reliability of findings, it may be helpful to repeat the measurements in the presence of abnormal values. The incidence of reduced AFV varies from 0. The etiologies vary according to the severity and the trimester in which oligohydramnios is diagnosed.

In the first trimester, oligohydramnios is a rare finding and is usually associated with a poor outcome. Causes include congenital heart anomalies, chromosomal aneuploidy, fetal demise, and ruptured membranes. At this stage oligohydramnios may also be due to iatrogenic causes ie, post chorionic villous sampling or its cause may be unknown.

Oligohydramnios is an infrequent finding in the second trimester. At this stage oligohydramnios may also be attributable to iatrogenic causes eg, ACE inhibitors or prostaglandin synthase inhibitors or unknown causes. In the second trimester, longer duration of oligohydramnios increases the risk of pulmonary hypoplasia, abnormal chest wall compliance, and limb deformities and contractures.

At term, oligohydramnios increases the risk of labor induction, the risk of category II fetal heart rate FHR tracings during labor, and recourse to cesarean delivery. Its effect on adverse neonatal outcome is less clearly documented. Insufficient evidence exists on which to base a recommendation for any intervention in the presence of borderline AFI 5. It is customary to monitor this condition eg, repeat AFV evaluation twice a week because it may worsen over time.

If a subsequent AFV evaluation is normal, surveillance can be discontinued. Ruling out fetal urinary anomalies, FGR, and PROM is important and can be done by assessing fetal anatomy if not done previously , measuring fetal biometry, and performing pertinent tests on vaginal secretions to confirm or rule out PROM ie, rapid dipstick tests. The type of assessment depends on the gestational age at the time oligohydramnios is diagnosed.

If visualization of fetal anatomy is hampered by oligohydramnios, transabdominal amnioinfusion can be considered Table 4. If the condition is compatible with perinatal survival, consultation with a pediatric urologist may shed light on the optimal timing for delivery in relation to fetal size and type of anomaly.

However, urinary anomalies typically have no impact on timing of delivery. If no comorbidities are found in a fetus shown to be growing normally, consider gestational age. A trial of maternal hydration can be attempted Box and the AFV can be reassessed a few hours later. In the presence of isolated and persistent oligohydramnios, fetal surveillance should be instituted twice weekly; delivery can be expedited for non-reassuring fetal testing or attainment of term pregnancy, when the potential risk associated with oligohydramnios is greater than that associated with delivery.

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.