Gestational Weight Gain: Historical Evolution of a Contested Health Outcome
Authors: Shenassa Edmond D. , Kinsey Celena , Moser Jones Marian , Fahey Jenifer 
Published: July 2017

The history of research on gestational weight gain (GWG) in the United States and United Kingdom provides a context for current clinical practice. We trace the evolution of research on GWG in scientific literature from the 19th century to the present and examine its implications for contemporary clinical and public health practice. Obstetricians, beginning in the late 1800s, recommended dieting during pregnancy in order to limit GWG to 20 lb or less, driven by a belief that excessive weight gain was a cause of toxemia. Beginning in the 1930s, a burgeoning focus on nutrition and health allowed a better understanding of the effect of GWG on the health of the fetus and the newborn. Increased awareness of disparities in infant mortality in the 1960s, followed by systematic review of the literature, produced further refinements in GWG recommendations in the 1970s, which continue today. Current research focuses on epigenetic influences over the life course and has emphasized individualized recommendations. The complex historical perspective that this article provides serves as a reminder of both the interplay and the gaps between research and practice. These gaps result from the fact that clinical guidelines often reflect a specific point in a perpetually evolving state of knowledge that is influenced not only by advances in bench research, but also by refinements in statistical and epidemiologic methods, as well as by the political realities of the time in which they are drafted.

Importance
Gestational weight gain and its relationship to maternal, fetal, and infant health are areas of active inquiry.

Objective
We critically review evolution of scientific understanding of GWG from the 19th century to the present, and examine its implications for contemporary obstetric practice.

Evidence Acquisition
We reviewed all English-language medical studies related to GWG published through 1930s as well as widely cited influential works from 1940s through present time.

Results
During the past century, recommendations for GWG have reversed from emphasizing dieting during pregnancy to the importance of proper nutrition during pregnancy. Obstetricians’ focus has also evolved from being exclusively on the newborn to include the health of mothers. Contemporary obstetric practice seeks to achieve a balance between mothers’ and infants’ risk of adverse outcomes.

Conclusions
Historical and social contexts of the United States and the United Kingdom led to distinct GWG policies in the 2 countries. Changes in GWG recommendations over the past century reflect developments in the allied fields, such as epidemiology and nutrition, as much as progress in obstetrics and gynecology.

Relevance
The complex historical perspective that this article provides serves as a reminder of both the interplay and the gaps between research and practice. These gaps result from the fact that clinical guidelines often reflect a specific point in a perpetually evolving state of knowledge that is influenced not only by advances in bench research, but also by refinements in statistical and epidemiologic methods, as well as by the political realities of the time in which they are drafted.

Target Audience
Obstetricians and gynecologists, family physicians.

Learning Objectives
After completion of this educational activity, the learner should be better able to describe how and why GWG recommendations changed over 100 years from dietary restriction during pregnancy to the current Institute of Medicine guidelines; distinguish how changing goals and roles of obstetricians influenced GWG recommendations; evaluate the role that nutrition science has played in evolving perspectives on GWG; identify the methodological errors that led to faulty conclusions about the dangers of “excessive GWG” and discern how these errors were corrected in subsequent research; explain the reasons behind the recent development of different GWG guidelines for different populations; contrast the differing US and UK approaches to GWG as they unfolded within diverging health care systems; and apply an understanding of historical debates in GWG to current controversies in GWG recommendations.