Dystocia in Numbers – Evidence-based Parameters for Intervention: Really Causes for Dystocia and When and How to Treat?

Introduction - Dystocia is defined as difficult birth, when a normal delivery of the fetus through the birth canal is disturbed and therefore impossible. The aim is to try to maximize neonatal survival and to protect the dams life both for ethical and also financial reasons (1). To understand causes of difficult birth and to get a diagnosis in timely manner knowledge of some cornerstones of normal parturition is essential:
Onset of parturition takes place 58-72 days after mating, 64-66 days from LH-Peak, 62-63 days from ovulation, 60-61 days from the first day of fertilisation, 58-59 days from the 1st day of cytologic diestrus. In most bitches, body temperature declines below 37°C 12-24 hrs. to beginning of expulsion (second stage labour), according to the prepartum decrease of progesterone level (<2-3 ng/ml). The first fetus usually comes from the uterine horn containing most puppies. Normally, the puppies are expelled alternately from both uterine horns(2). Dystocia can result from maternal causes (birth canal, uterine, abdominal forces), from fetal causes (oversize, faulty disposition, fetal death), or a combination of both (3,4,5,6,7). Depending on the causes for dystocia and on the variation of duration of expulsion time from several to nearly 24 hours early diagnosis and therefore decision for a prompt and correct intervention are sometimes difficult to make. Diagnostic problems make some obstetric cases to court cases. Therefore, there is really a need for new diagnostic approaches with reliable information, e.g. concerning the status of uterine contraction patterns or the time that is left to get living puppies with high probability. [...]