Comparison of alterations in fetal regional arterial vascular resistance in appropriate-for-gestational-age singleton, twin and triplet pregnancies

The objective of this longitudinal study was to evaluate alterations in fet al vascular resistance of fetal peripheral arteries with advancing gestatio n in singleton appropriate-for-gestational-age (S-AGA), twin appropriate-fo r-gestational-age (Tw-AGA) and triplet appropriate-for-gestational-age (Tri -AGA) infants. Colour Doppler how imaging and pulsed Doppler ultrasonograph ic examinations were performed on 35 S-AGA, 52 Tw-AGA and 12 Tri-AGA fetuse s. The pulsatility index for middle cerebral artery (MCAPI), umbilical arte ry (UAPI), descending aorta (DAPI), splenic artery (SAPI), renal artery (RA PI) and femoral artery (FAPI) was measured as vascular resistance every 2 w eeks after 15 weeks of menstrual age until delivery. Optimal models and nor mal ranges for pulsatility index for each artery in each group were generat ed. The alterations in various fetal regional arterial pulsatility indices with advancing gestational age showed no significant differences in S-AGA, Tw-AGA and Tri-AGA infants, respectively. These results suggest that there is no significant difference for regional arterial vascular resistance in A GA fetuses among singleton, tw in, and triplet pregnancies, whereas there w as a slight difference in fetal growth pattern among singleton, twin, and t riplet pregnancies described in our previous investigation.