Is it safe to take penicillin in early weeks of pregnant?

If your doctor knows you are pregnant and you are not allergic, take it, he is prescribing it because it is the best antibiotic for your condition. Your baby is probably safe from the penicillin, but the infection may harm it. If a medication is going to damage a baby it is more likely in the early weeks as this is when the baby is forming. In the last weeks of pregnancy it is fully formed and is just maturing and putting on weight.