Pregnancy is occasionally complicated by infections that necessitate antibiotic therapy. When considering therapeutic options for pregnant women, both the physiologic changes of pregnancy and the prenatal effects of the drug must be weighed. Antibiotics should be selected with regard to the trimester of pregnancy. Some antibiotics are safe for use throughout pregnancy, while others are completely contraindicated. Choosing the proper antibiotic requires balancing the seriousness of the infection with the antibiotic's safety and antimicrobial activity.