It said there may be an increased risk of miscarriage in this period, despite uncertainty over whether an occasional drink would harm the foetus.
Dr Gillian Leng, NICE deputy chief executive, said: ‘If they do choose to drink while pregnant, women should be advised to drink no more than one to two units once or twice a week.’
The guidance also said that screening for sickle cell diseases and thalassaemias should be offered as early as possible.
In separate guidance on women with diabetes planning for pregnancy, NICE said women should aim to keep fasting blood glucose between 3.5 and 5.9mmol/l.
Jackie Webb, diabetes nurse specialist and guideline development group member, said: ‘Women with diabetes in pregnancy are at a higher risk of complications but with the right care these risks can be minimised.’