To get human retinal cells at the same stage of development, however, would involve taking stem cells from a foetus during the second trimesterofpregnancy.
Those taking part in the study will be asked to go to the antenatal suite at Singleton Hospital in Swansea once during each trimesterof their pregnancy and again three months after their baby is born.
"Pregnant women are recommended to get a haemoglobin test at least once in every trimesterof their pregnancy but it is inconvenient for a women to walk to the nearest primary healthcare centre that could more than 5km away, " he said.