Birthweight placental weight ratio of appropriate-for-dates and light-for-dates infants in preterm delivery.
Although birthweight placental weight ratio (BPR) may be a promising indicator which reflects pathophysiology of fetal growth restriction (FGR), the standard of BPR changes throughout gestation in a Japanese population has not been established as far as we know. Therefore, we first examined BPR of appropriate-for-dates (AFD) infants in each gestational week in preterm deliveries. We then compared it with that in a group of light-for-dates (LFD) infants born from mothers with and without pregnancy-induced hypertension (PIH). Placentas of a singleton pregnancy with 373 AFD and 110 LFD infants delivered from 22 to 36weeks of gestation in our hospital during the period between September 2000 and December 2008 were included. We examined the placental weight and BPR of each gestational week in AFD and LFD groups. And the mean BPR and placental weight in the three groups (AFD: LFD with PIH: LFD without PIH) were compared according to gestational periods. The placental weight and BPR were significantly correlated to the gestational week both in AFD and LFD groups. We found that although the mean BPR in LFD-PIH(-) group was significantly lower than those both in AFD group and in LFD-PIH(+) group in 22-29weeks, the mean BPR in 30-36weeks was not statistically different among these three groups. Our result in the AFD group may be useful as one of the standards of BPR changes throughout gestation in a Japanese population for future studies. We believe that BPR may be a clinically useful indicator which reflects pathophysiology of FGR.