Causes of IUGR in the second trimester

Sometimes a fetus measures small because the pregnancy dates differ from those first estimated or because small size runs in the family. A single measurement cannot reliably separate a constitutionally small fetus from restricted growth, so clinicians assess the pattern and wider findings.

The placenta may not transfer oxygen and nutrients as effectively as needed. Maternal high blood pressure, kidney disease, autoimmune illness, severe anaemia, smoking or substance exposure can contribute. Fetal chromosome or structural differences and certain infections are also considered, especially when restricted growth appears early or accompanies an ultrasound finding.

A detailed growth scan checks fetal measurements, anatomy, amniotic fluid and blood-flow patterns. Comparing scans over time shows growth direction more clearly than one estimate. The team may revisit pregnancy dating and offer targeted blood tests or diagnostic discussions based on the scan and medical history.

Attend the planned specialist and ultrasound appointments, because the interval pattern guides care. The team may monitor your blood pressure, urine, blood results, fetal anatomy, placental blood flow and growth. Take prescribed medicine as directed and tell the team about nicotine, vaping, recreational substances and all other products so support can be tailored safely.

There is no home remedy that makes a restricted fetus grow faster. Regular meals, appropriate pregnancy nutrition and rest support general health, but they do not replace surveillance. Decisions about further testing and timing of birth depend on the overall maternal and fetal picture.

Contact your maternity unit urgently for vaginal bleeding, leaking fluid, severe abdominal pain, a severe or persistent headache, visual disturbance, sudden swelling of the face or hands, chest pain, breathing difficulty, or feeling very unwell. These symptoms require assessment independently of how small the fetus measures.

Follow the maternity team's advice about fetal movement. Movement patterns may not yet be consistent early in the second trimester, but a clear reduction after movements have become familiar should be reported promptly rather than watched at home.

Ask whether pregnancy dating is secure, whether growth is proportionate, whether anatomy or placental blood flow looks unusual, which maternal conditions are being checked, and when another scan is planned. You can also ask what findings would change monitoring, prompt diagnostic testing or lead to discussion of earlier birth.