IUGR and oligohydramnios: what should you know?

IUGR means the baby is measuring smaller than expected or has not followed the expected growth pattern. Oligohydramnios means there is less amniotic fluid than expected on assessment. Ultrasound fluid measurements are interpreted with gestational age, fetal growth, placenta-related blood flow, kidney and bladder observations, and the wider clinical picture. Low fluid can occur for different reasons, including fluid leakage or reduced placental function, so the scan label does not identify a single cause. Neither finding alone tells you exactly when birth will be needed.

Expect closer contact with your maternity service and attend reviews as scheduled. A growth scan can reassess size and fluid, while blood-flow measurements help evaluate placental circulation. Your team may also check blood pressure, ask about fluid leakage and assess fetal movements. Keep track of your baby’s usual movement pattern and follow the instructions given for returning if it changes. If the findings remain concerning, clinicians may discuss hospital observation or induction of labour; the recommendation depends on the full assessment.

Call your maternity unit immediately if you think fluid is leaking, movements are reduced or changed, or you have bleeding, regular painful contractions or severe abdominal pain. Severe headache, vision changes, sudden swelling or feeling seriously unwell also warrant urgent review. Do not wait for a routine scan when these symptoms occur, because they may need assessment independently of the ultrasound findings.

Ask how low the fluid appears and whether fluid leakage has been excluded. Ask what the growth and blood-flow measurements show, how often a growth scan is needed, and which movement changes require immediate contact. Ask what would make the team recommend hospital review, induction of labour or another birth plan, and who to call outside clinic hours.