There's a very strong link between drinking and birth defects. I understand that there are issues with setting this with regards to precedent, but expectant mothers should not have the capacity to put their children through excess harm.

I know it is at least frowned upon, from my country, anyway. I'm not sure about what laws surround it, but I know that women still do it sometimes and I believe it causes fecal alcohol spectrum disorder and causes birth defects. I also believe that it has been researched and there is 'no safe level of alcohol to drink while pregnant'... some women drink occasionally while pregnant and their children have turned out fine, but, is it an unnecessary risk? Very likely so. It has also been pointed out that some women have more of the specific enzyme that breaks down alcohol, while some women have less of it and the alcohol circulates in their system for longer.

My personal opinion is that it should be completely avoided, because there is more chance of it causing harm, than not.

Not sure what you mean by "ban" here...

I would suspect that most women who have access to education and healthcare during their pregnancy would be advised not to drink alcohol. So by "ban", are we talking a legal intervention here? Criminalising women's alcohol consumption...?

The biggest issue here is education. Many women simply don't know that alcohol can have an effect on their unborn child. We need better education for families, not more pathologisation.