Infection presents a particular challenge in pregnancy. Symptoms of infection may be subtle, unusual in presentation, or masked by other pregnancy-related symptoms. Infection may affect both the mother and fetus; antibiotic choices may be limited by concerns related to pregnancy and fetal development. As with most elements of obstetrical care, management of infection in pregnancy ideally begins in the preconception period. The preconception history can provide important data concerning infection risk such as recent exposures (toxoplasmosis, tuberculosis, cytomegalovirus), immunization status (influenza, measles, and varicella), and chronic infectious conditions (HIV, herpes, viral hepatitis). For some of these infections, appropriate preconception planning and risk reduction are the only effective intervention. A thorough physical examination may reveal evidence of such infections as active herpes, gonorrhea, or chlamydia. Preconception screening for HIV, tuberculosis, and syphilis, among other conditions, may allow for treatment prior to pregnancy, thereby decreasing the likelihood of adverse prenatal outcomes. Pregnancy is associated with increased risk for infections with influenza and COVID-19.