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 during early pregnancy influence placental growth and subsequently the cardiovascular system as assessed non-invasively by ultrasonography in the sheep fetus.
Methods: 21 ewes bearing singletons of uniform age were randomly assigned for the first half of pregnancy to one of the following study groups: fed 100% of their nutritional requirements (i.e. controls), global reduction in total 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 three dietary groups for either the aortic or the umbilical Doppler velocimetry parameters and the fetal heart rate or heart size.
Conclusions: The present study shows that early mild maternal undernutrition produces subtle changes in cotelydonary weight. However, Doppler and echocardiographic parameters were not affected by these changes.