Pregnant women should be breath-tested during antenatal visits to check whether they are smoking, a new Irish study recommends.

Women who hide their smoking habit miss out on vital monitoring of their pregnancy and end up having more problems as a result, according to the study of women attending the Coombe hospital in Dublin.

It found a substantial number of women with high carbon monoxide levels – an indicator of smoking – had not declared their tobacco use.

The authors, from the Coombe and University College Dublin, said this finding strengthens the case for universal BCO screening at the first antenatal visit. A high reading should result in referral of the woman to smoking cessation services and close monitoring of the baby, they say.

Women who fail to disclose their smoking do not get the level of monitoring during pregnancy they and their unborn child actually require, the study, published in the European Journal of Obstetrics & Gynecology and Reproductive Biology, points out.