Growth parameters in mid-trimester fetal Turner syndrome

Growth failure is a consistent finding at birth in infants with Turner syndrome. However, the time of onset and pattern of growth deficiency is unknown. To determine the presence of growth failure in the second trimester in fetuses with Turner syndrome, second trimester fetuses that had a complete autopsy at the Central Laboratory for Human Embryology at the University of Washington were studied. A control group of specimens with normal findings was selected and compared with a study group with Turner syndrome documented by karyotype. Footlength and crown-rump length were measured directly with a ruler and femur, tibia, fibula, humerus, ulna and radius were measured from X-rays. Crown-rump length was used as the indicator of gestational age. Statistical comparisons between the normal and study groups were performed by multiple regression. Long bone measurements were made on 105 normal and 13 Turner fetuses. Footlength and the six long bones showed evidence of statistically significant growth failure. Fetuses with 45,X/46,XX mosaic Turner syndrome may demonstrate a lesser degree of growth retardation, at least for footlength, than those with a 45,X karyotype, but small numbers limited the analysis. We conclude that the growth failure consistently demonstrated in newborns with Turner syndrome begins early in gestation and is well-established by mid-pregnancy.