A–Z Glossary

Polyhydramnios

Idiopathic polyhydramnios is excess amniotic fluid for which no definite underlying cause can be identified.

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Search results for: Polyhydramnios

Non-stress test (NST) and biophysical profile (BPP)

Non-stress test (NST) and biophysical profile (BPP)

What is a non-stress test? A non-stress test, or NST, is a fetal monitoring test that records the fetal heart rate over time, usually along with uterine activity. It is called “non-stress” because it does not intentionally stress the fetus or trigger contractions. Instead, it observes the fetal heart rate pattern under usual conditions. The […]

Anatomy scan (20-week ultrasound)

Anatomy scan (20-week ultrasound)

What is the anatomy scan? The anatomy scan is a structured ultrasound examination performed in the second trimester to evaluate fetal anatomy and growth. It is commonly called the 20-week ultrasound because it often takes place near the halfway point of a 40-week pregnancy, though the usual window is approximately 18 to 22 weeks. Unlike […]

Oligohydramnios and polyhydramnios explained

Oligohydramnios and polyhydramnios explained

Why amniotic fluid matters Amniotic fluid is not simply “water around the baby.” In early pregnancy, it is largely derived from maternal plasma and fluid movement across fetal membranes. Later, fetal urine becomes a major contributor, while fetal swallowing, lung fluid movement, membrane exchange, and placental dynamics help regulate the total volume. Because production and […]