«If I was unaware of being pregnant, but still had alcohol on two separate occasions, what is the likelihood of that affecting the baby?»
Congratulations on your pregnancy! You are not the only one that has drunk before finding out you were pregnant (for what is worth- it happened to me also). Think that nearly half of all pregnancies in the US are unplanned, so there are lots of people that have been in your situation.
There is little reason to panic if you had some drinks. The American College of Obstetricians and Gynaecologists and the UK Royal College of Obstetricians and Gynaecologists both say harm from having a little alcohol before you were pregnant is unlikely.
The important thing is that now you know you are pregnant, that you stop drinking alcohol. There is no known safe amount of alcohol use during pregnancy so it is better not to have any at all. If you want more information, check the US Center for Disease Control and Prevention (CDC) guidelines and the advice from the NHS in the UK.
Try not to dwell in the past and enjoy your pregnancy. I wish you all the very best!
Ana
