GESTATION 



100.^ 



adrenal corticoids in pregnancy is con- 

 cerned with stimulation of appetite and 

 mobilization and degradation of proteins 

 to amino acids. The latter action would 

 permit the replacement of body protein in 

 the absence of a normal jirotcin intake. 



C. PANCREAS 



The impact of diabetes mellitus on the 

 course of pregnancy has been of interest 

 to the clinician for many years. In a recent 

 review of the subject, Reis, DeCosta and 

 Allweiss (1952) came to the conclusion that 

 "the carefully controlled diabetic aborts 

 no more frequently than the nondiabetic." 

 On the other hand, it has been well known 

 for many years that uncontrolled diabetes 

 and pregnancy are basically incompatible 

 (Eastman, 1946). 



Studies in the rat have given contro- 

 versial results with regard to the influence 

 of insulin on pregnancy. Davis, Fugo and 

 Lawrence (1947) reported that in the al- 

 loxan diabetic rat pregnancy was normal for 

 the first 12 days. Thereafter death of the 

 fetuses occurred followed by resorption. 

 Sinden and Longwell (1949) and Levi and 

 Weinberg (1949) reported no detrimental 

 effect from diabetes on the course of i^reg- 

 nancy. The latter group obtained 12 preg- 

 nancies from 25 rats made permanently dia- 

 betic with alloxan. Eleven of the 12 rats 

 went to term and delivered normal fetuses 

 and 1 died during pregnancy. Recently, 

 Wells, Kim, Runge and Lazarow (1957) 

 reported a 14 per cent loss in fetal weight, 

 an increase in gestation length from a nor- 

 mal of 538 to 563 hours, and an increase in 

 fetal or neonatal mortality in the pregnant 

 rat made diabetic by pancreatectomy or 

 treatment with alloxan. 



In general, the clinical data indicate that 

 uncontrolled diabetes has a detrimental ef- 

 fect on pregnancy, but that the abortion 

 rate in the controlled diabetics approaches 

 that seen in the ''normal" population. Since 

 the crux of the matter seems to hinge on the 

 severity of the diabetes, one might conclude 

 that the effect of insulin is an indirect one 

 by virtue of its action in maintaining a good 

 metabolic state. The conflicting reports 

 from animal experimentation may be due 



to the differences resulting from uncon- 

 trolled environmental and dietary factors. 



D. ovary: progesterone, estradiol, 



AND RELAXIN 



Marshall and Jolly (1905) were probably 

 the first to point out that ovariectomy dur- 

 ing pregnancy leads to abortion or resorp- 

 tion of the fetuses in the rat. Subsequently, 

 a number of investigators repeated these 

 experiments and confirmed the findings in 

 all species tested thus far, provided ovariec- 

 tomy is performed before implantation. Re- 

 moval of the ovaries after gestation is well 

 under way, however, does not disturb the 

 course of pregnancy in all species. The hu- 

 man being, monkey, horse, ewe, and cow are 

 examples of species not dependent on the 

 ovary for the maintenance of pregnancy 

 once it has been well established. Species 

 such as the rabbit and the rat require the 

 presence of the ovary throughout preg- 

 nancy. 



The importance of progesterone for i)reg- 

 nancy was established by Allen and Corner 

 (1929) who first showed that an extract 

 of the corpus luteum will maintain preg- 

 nancy in the castrated rabbit. Identification 

 of the active substance in the extract as 

 progesterone led to the use of the hormone 

 in many other species. Allen (1937) reported 

 that crystalline progesterone was inferior 

 to the crude luteal extract in the mainte- 

 nance of pregnancy in the castrated rabbit. 

 From these and other data, such as the en- 

 hancing action of estrogen on the proges- 

 terone-induced progestational reaction, he 

 inferred that a combination of estrogen and 

 progesterone should be superior to proges- 

 terone alone in the maintenance of preg- 

 nancy. However, he pointed out with proper 

 caution that the dosages would have to be 

 carefully regulated because estrogen could 

 also antagonize progesterone. Although Rob- 

 son (1936) failed to enhance the action of 

 progesterone with estrone in the pregnant 

 hypophysectomized rabbit, Pincus and 

 Werthessen (1938) obtained enhancement 

 with both the androgens and estrogen. 

 Whereas the early work indicated that a 

 pregnancy maintenance dose of progester- 

 one varied from 0.5 to 2 mg. (Allen and 

 Corner, 1930), later experimentation indi- 



