Pregnancy is accompanied by a progressive increase in the basal oxygen consumption. There is, moreover a considerable amount of evidence tending to support the view that the thyroid is involved in the metabolic reaction of the normal woman to pregnancy. A group of Ohio State investigators1 have recently reported a study of the factors affecting the increase in metabolism occurring in pregnancy, the urinary iodine excretion and the effects of advancing pregnancy on vital capacity and tidal air.
Eight subjects were used in these studies. Seven were primiparas ranging in age from 15 to 20 years, who were inmates of a home for unmarried mothers and therefore had uniform dietary and sleeping habits. All were normal cases of pregnancy terminating in uncomplicated labor and healthy infants. None of them showed any symptoms of thyroid dysfunction.
All determinations of basal metabolism were made by means of the closed circuit type
BASAL METABOLISM AND IODINE EXCRETION DURING PREGNANCY. JAMA. 1935;105(19):1525–1526. doi:10.1001/jama.1935.02760450045014