Effects of the Estrus Cycle and Pregnancy on Echocardiographic Variables in Healthy Bitches

Dog exam

Purpose of Study: 

Pregnancy causes changes to the mother’s cardiovascular system related to the demands of carrying fetuses. These changes are well-described in human women, but have not been well-described in dogs. The purpose of this study is to better characterize the changes in the canine cardiovascular system throughout the estrus cycle and pregnancy, and to determine whether fetal echocardiography can tell us information about the cardiovascular demand of large litters of puppies. 

Eligibility: 

Intact breeding female dogs at the start of their reproductive cycles (just coming into heat) are eligible for enrollment in this study. The first visit will occur on day 3-5 of bleeding, and you must plan to breed the bitch during that cycle.

All visits will be scheduled through the ISU Theriogenology Service. 

Client Responsibilities: 

If you agree to have your bitch participate in this study, the participation will last for 4 visits to the hospital over the span of 5 months. You must be able to commit to bringing your bitch to the LVMC for all 4 visits. The first visit will occur in proestrus during day 3-5 of bleeding. The second visit will occur in early pregnancy at day 25-30 post-ovulation (to confirm pregnancy). If your dog is not found to be pregnant at that visit, she will be removed from the study. If your dog is pregnant, the third visit will occur during late pregnancy at day 45-60 post-ovulation. The fourth and final visit will occur during the nonreproductive period (anestrus), approximately 1 month post-weaning of the previous litter. During the study, you may expect the following procedures to be used: physical examination, vaginal examination, vaginal cytology, blood sample collection for progesterone levels and blood cell counts, noninvasive blood pressure measurement, echocardiography (heart ultrasound), fetal echocardiography (ultrasound of the mother’s abdomen to look at fetal hearts), and abdominal X-rays to count fetal number.  Your dog will be gently restrained (standing, sitting, or lying down) for all procedures.

Client Benefits: 

All study costs during the 4 study visits will be paid for by the study, including visit fees, progesterone levels, blood pressure measurement, echocardiography, fetal echocardiography, and abdominal X-rays.  At the conclusion of the study (at the anestrus visit), dogs will have OFA certification forms completed by a boarded cardiologist at no charge. You will be responsible for any other costs associated with breeding management and pregnancy, including all costs incurred at visits other than the 4 study visits, and any other testing deemed necessary during study visits.

Contact: 

Dr. Jessica Ward
515-294-4900