Mild maternal undernutrition in the first half of ovine pregnancy influences placental morphology but not fetal Doppler flow velocity waveforms and fetal heart size

Aims. We wanted to investigate whether experimental dietary manipulations d uring early pregnancy influence placental growth and subsequently the cardi ovascular system as assessed non-invasively by ultrasonography in the sheep fetus. Methods. 21 ewes bearing singletons of uniform age were randomly assigned f or the first half of pregnancy to one of the following study groups: fed 10 0% of their nutritional requirements (i.e. controls), global reduction in t otal intake by 30% (i.e. 70% global) and reduction in protein intake by 30% (i.e. 70% protein). Results. Placentas from the 70% protein group had significantly more small placentomes, but significantly fewer large placentomes compared to the 70% global group. However, there were no significant differences between the th ree dietary groups for either the aortic or the umbilical Doppler velocimet ry parameters and the fetal heart rate or heart size. Conclusions. The present study shows that early mild maternal undernutritio n produces subtle changes in co-telydonary weight. However, Doppler and ech ocardiographic parameters were not affected by these changes.