Private maternity services might be able to offer women some advice when it comes to drinking alcohol during pregnancy.
But the number of conflicting reports and studies mean that the safest option for many women is to drink no alcohol at all while pregnant.
Jacqui Clinton, health campaigns director for Tommy's, said that the number of mixed messages regarding alcohol and pregnancy can be confusing for mums-to-be.
She added: "Because more research is clearly needed into what actually constitutes a safe level, we say that the safest level of alcohol to drink in pregnancy is none."
Earlier this year, a report in the BMC Pregnancy and Childbirth journal confirmed that research on a drinking while pregnant is often conflicting.
However, drinking while pregnant is associated with an increased chance of premature birth.
Ms Clinton added that there are a number of other lifestyle factors that can influence pregnancy in this way, including being over or under weight, smoking and having a poor diet.