A clinician quotes the WHO haemoglobin threshold for diagnosing anaemia in pregnancy. Which single value is correct?

Answer: A. Below 11 g/dL

Defining anaemia in pregnancy

Pregnancy lowers the haemoglobin through plasma volume expansion (physiological/dilutional anaemia), so a pregnancy-specific threshold is used.

Threshold

• The WHO threshold is a haemoglobin below 11 g/dL throughout pregnancy.
• In practice, below 10.5 g/dL is often used as the cut-off in the second and third trimesters.

Why it matters

• Anaemia increases the risks of preterm birth, low birth weight, poor tolerance of blood loss at delivery, and (if severe) heart failure.

So anaemia in pregnancy is a haemoglobin below 11 g/dL.