The evolution of prenatal care delivery guidelines in the United States.

The coronavirus disease 2019 pandemic led to some of the most drastic changes in clinical care delivery ever seen in the United States. Almost overnight, providers of prenatal care adopted virtual visits and reduced visit schedules. These changes stood in stark contrast to the 12 to 14 in-person prenatal visit schedule that had been previously recommended for almost a century. As maternity care providers consider what prenatal care delivery changes we should maintain following the acute pandemic, we may gain insight from understanding the evolution of prenatal care delivery guidelines. In this paper, we start by sketching out the relatively unstructured beginnings of prenatal care in the 19th century. Most medical care fell within the domain of laypeople, and childbirth was a central feature of female domestic culture. We explore how early discoveries about "toxemia" created the groundwork for future prenatal care interventions, including screening of urine and blood pressure-which in turn created a need for routine prenatal care visits. We then discuss the organization of the medical profession, including the field of obstetrics and gynecology. In the early 20th century, new data increasingly revealed high rates of both infant and maternal mortalities, leading to a greater emphasis on prenatal care. These discoveries culminated in the first codification of a prenatal visit schedule in 1930 by the Children's Bureau. Surprisingly, this schedule remained essentially unchanged for almost a century. Through the founding of the American College of Obstetricians and Gynecologists, significant technological advancements in laboratory testing and ultrasonography, and calls of the National Institutes of Health Task Force for changes in prenatal care delivery in 1989, prenatal care recommendations continued to be the same as they had been in 1930-monthly visits until 28 weeks' gestation, bimonthly visits until 36 weeks' gestation, and weekly visits until delivery. However, coronavirus disease 2019 forced us to change, to reconsider both the need for in-person visits and frequency of visits. Currently, as we transition from the acute pandemic, we should consider how to use what we have learned in this unprecedented time to shape future prenatal care. Lessons from a century of prenatal care provide valuable insights to inform the next generation of prenatal care delivery.