Ultrasound observations of fetal movements in the pig: an exploratory study

Abstract We studied the feasibility and practical conditions of repeated, non-invasive ultrasound scanning for fetal movements during late gestation in the pig. It appeared that, after a short training period of the sow, good quality recordings of fetal movements can be obtained for 60 min when using a 3.5 MHz ultrasound transducer of 12 or 18 cm long. Four different movement patterns were discerned in the fetal pig: general movement, isolated head and (fore)limb movements, and rotation. Head movements were the predominant types of fetal activity. Preliminary data are provided on their rate of occurrence. The observed large variation in movement incidence (% of time or number per hour) was found to be related to the gestational age at recording and in part to the size of the transducer. There was evidence of a decreasing trend in fetal activity towards parturition. This exploratory study demonstrated that longitudinal study on fetal movements in the pig is feasible. This approach also permits quantitative analysis of fetal motility under different (patho-) physiological and management conditions.