The correlation between the physiological state of the thyroid of the mother and of the fetus

Abstract

The starting point of this investigation was some observations (incidental to other work on the thyroids) that pups born of mothers having active hyperplasia of the thyroids seemed to have much larger thyroids than the pups born of mothers with normal thyroids or with colloid goiters. The size of the thyroid in pups from mothers with marked thyroid hyperplasia is in many cases so great that they produce the distortion of the neck similar to goiter in adults. These pups are apparently born with goiter.

The work was begun in the spring of 1912, and so far data have been obtained on mother and offsprings in the case of 16 cats and 14 dogs; the work is being continued and extended to other species.

It is well known that goiter (active hyperplasia and colloid) is prevalent in dogs in the Great Lakes region of United States, while in cats in the same region goiter is practically unknown. The goiter of the newborn of mothers with thyroid hyperplasia may be (1) primarily hereditary, that is, due to defects in the germ plasm, or (2) it may be due to some temporary metabolic disturbance in the mother,—toxins or abnormal concentration of normal products of metabolism, acting alike both on the maternal and on the fetal thyroid. If the fetal goiter is due primarily to the constitution of the ovum rather than to the maternal environment during intrauterine life, we would expect the goitre to persist in varying degrees after birth.

1. Results in Dogs.—During intrauterine life the body increases in weight faster than the thyroid gland so that the ratio of the weight of the thyroid to the body weight becomes gradually larger. But in the case of mothers with normal (or nearly normal) thyroids, the ratio of thyroid to body weight is always greater in the mother than in the pups; in the case of mothers with colloid glands the ratio may be greater in the pups than in the mother while in the case of mothers with thyroid hyperplasia the ratio may be the same, or it may be higher or lower, depending on the degree of hyperplasia of the maternal thyroid.