What is the normal range for the amniotic fluid index at 39 weeks of pregnancy?

The amniotic fluid index (AFI) is a critical parameter physicians use to assess whether a pregnant woman’s amniotic fluid volume is within the normal range. The AFI can be measured via B-mode ultrasound (B-ultrasound). Specifically, the uterus is divided into four quadrants—left upper, right upper, left lower, and right lower—and the maximum vertical depth of amniotic fluid in each quadrant is measured separately; the four measurements are then summed to obtain the AFI. So, what is the normal AFI range at 39 weeks of gestation?

What Is the Normal Amniotic Fluid Index at 39 Weeks’ Gestation?

At 39 weeks’ gestation, the normal AFI range is 8–25 cm. An AFI exceeding 25 cm is termed polyhydramnios (excessive amniotic fluid), whereas an AFI below 5 cm is termed oligohydramnios (insufficient amniotic fluid). An AFI between 5 and 8 cm is also classified as oligohydramnios.

At 39 weeks’ gestation, the pregnancy is considered full-term. If the AFI falls below 5 cm, prompt termination of pregnancy is indicated. Prolonged delay increases the risk of fetal hypoxia. If cervical conditions are favorable, artificial rupture of membranes (AROM) may be performed first, followed by assessment of amniotic fluid color. If the fluid appears clear and normal, intravenous oxytocin infusion may be initiated to induce labor. However, if the fluid is discolored (e.g., meconium-stained or turbid), immediate cesarean delivery is warranted to terminate the pregnancy.

Both polyhydramnios and oligohydramnios can adversely affect normal fetal development. Pregnant women should undergo routine B-ultrasound examinations as scheduled to continuously monitor their health status. During pregnancy, maintaining comprehensive and balanced nutrition is essential. Moderate outdoor activity is encouraged to promote physical well-being and emotional relaxation. We hope this information proves helpful!