Is C-type natriuretic peptide a maternal marker of fetal growth restriction and hypoxaemia?

Failure of the placenta to supply enough nutrition and oxygen to a baby during pregnancy can lead to fetal growth restriction (FGR) and small size at birth. FGR also decreases a baby’s chances of survival and can have negative consequences for health throughout life.

Current methods – ultrasound or simply measuring a pregnant woman’s tummy – can miss at least a third of FGR cases in New Zealand. These missed cases are at increased risk of stillbirth and other serious health complications.

FGR is usually accompanied by low oxygen content in the baby’s blood, because the placenta is not working properly. Measuring fetal blood oxygen content in utero is not possible in human babies as a routine screening, but we can measure blood oxygen content in fetal sheep blood.

A hormone called C-type natriuretic peptide (CNP), found in the maternal blood of both humans and sheep, may be a marker of low fetal blood oxygen and FGR. While promising, the data we have is still quite limited.

A team from the universities of Auckland and Otago is conducting research using sheep. The study will thoroughly investigate whether CNP in maternal blood could be a useful test for FGR and low fetal oxygen. This would enable more reliable detection using an inexpensive, non-invasive test that doesn’t require specialist skills.

Funding from Cure Kids is enabling this interesting project, which could lead to research in humans and a simple way to significantly improve the diagnosis of fetal growth restriction.