Pregnant women are being warned too many multi vitamins can do more harm than good

An Australian study reveals almost 90-percent of participants were using supplements to meet dietary requirements during pregnancy.

Lead researcher Dr Linda Gallo says over supplementing can pose health risks for both mother and baby, including diabetes, preeclampsia, low birth weight and poorer neurodevelopment outcomes for the child.

She says food is where good nutrition starts and will usually minimise the need for supplements.