Pregnancy Monitoring and Management of High Risk Pregnancy in the Dog

All pregnancies are high risk. The well being of both the dam and the fetuses is jeopardized by the process. Pregnancy physiologically and physically stresses the dam’s metabolism and body, affecting every organ system directly or indirectly. Maternal cardiac output and renal tubular perfusion increase. The immune system is mildly suppressed by progesterone (P4) and concomitantly challenged by the presence of foreign proteins on the embryo and placenta. The gastro-intestinal system must increase nutritional absorption while being compressed. The skin is stretched. The musculoskeletal system is forced to bear greater weight while having its underlying support system stripped away one calcium atom at a time. The dam’s pulmonary effort is increased, and the hepatic system is working overtime trying to compensate for increase energy demands, alternating glucose excesses and deficiencies, increased toxins and increased hormone metabolism. Given the array of physical challenges, it is truly amazing how rarely we see pregnancy associated disease of the dam.

Gestational Diabetes Mellitus (GDM), also called Preg- nancy-Induced Insulin Resistance is perhaps the most significant metabolic condition we see in the pregnant bitch; and it can be life-threatening. P4 and growth hormone induce insulin resistance, by some as yet unknown mechanism, at the level of the insulin receptors.1 The resulting decreased cellular uptake of glucose, in the presence of normal or elevated insulin levels, results in hyperglycemia which eventually spills out into the urine, creating the characteristic polyuria/ polydypsia of DM. If the condition persists long enough and the cells become deprived of glucose, ketones accumulate in the circulation resulting in diabetic ketoacidosis. Management of GDM requires careful monitoring of the dam and higher than expected insulin doses to control hyperglycemia. Termination of the pregnancy by C-section may be necessary to remove the offending P4. If C-section is done on or after day 62 from the LH surge (d62), fetal survival is possible as fetal lung maturation should be complete.2 After whelping, most bitches return to euglycemia; however, some will remain permanently afflicted. Ovariohyster- ectomy is recommended to prevent GDM from reoccurring in subsequent pregnancy or diestrus (under the influence of P4).  [...]