Fetal growth and fetal glucose and C-peptide levels in relation to the degree of anemia in fetuses affected by rhesus iso-immunization.

Fetal growth rate was determined by measuring the fetal biparietal diameter at 63 two-week time points during the second trimester in 14 patients with severe Rhesus isoimmunization. Growth rate was found to be related to the fetal hemoglobin concentration which was determined at the end of each 2-week period. Fetuses with a hemoglobin concentration of less than 30% of the normal value had a significantly decreased growth rate (p less than 0.01). These fetuses had also reduced C-peptide (p less than 0.05) and increased glucose levels (p less than 0.1) compared with less anemic fetuses. The physiological background to impaired fetal growth in cases of severe fetal anamia at Rhesus iso-immunization is discussed.