Placenta flow index in posterior wall placentas measured with 99mtechnetium-labelled human serum albumin.

Measurement of the perfusion of posterior wall placentas with the isotope technique may pose a problem owing to attenuation of the gamma radiation. The present investigation compares the placenta flow index (PFI) in 34 pregnant women with anterior wall placenta and 13 with posterior wall placenta. We found no difference in the shortest skin-to-placenta distance on ultrasound scanning and no difference in PFI between the anterior and the posterior wall placentas.