Association of placental histology with the pulsatility index of fetal and uteroplacental vessels during pregnancy and with birthweight z-score

Abstract

Aims: To compare macro- and microscopic features of the placenta with the pulsatility index (PI) of the uterine (UtA), umbilical (UA) and middle cerebral arteries (MCA) at 20-24 and 34-38 weeks’ gestation, and with birthweight z-scores (BWZS). Methods: Recruitment for the XXX Study (XXX), which investigated the association of alcohol and tobacco use with stillbirth and sudden infant death syndrome, were done from August 2007 to January 2015 at community clinics with assessments at XXX Hospital in XXX, XXX. The population represents a predominantly homogenous population of pregnant women from a low socioeconomic residential area. This study is a further analysis of the data of the XXX. It consists of 1205 singleton pregnancies for which placental histology was available, of whom 1022 and 979 had fetoplacental Doppler examinations at 20-24 and 34-38 weeks, respectively, and 1035 had a known BWZS. Features of the placenta were assessed according to international norms. Results: Significantly higher ORs for the presence of individual and combined features of maternal vascular malperfusion (MVM) were found with lower BWZS and higher UtA PI values, more consistently than with higher UA PI values. Strongest associations were for a small placenta (UtA OR 4.86 at 20-24 and 5.92 at 34-38 weeks; UA OR 5.33 at 20-24 and 27.01 at 34-38 weeks; low BWZS OR 0.31), for macroscopic infarction (UtA OR 6.08 at 20-24 weeks; UA OR 17.02 at 34-38 weeks; low BWZS OR 0.62), for microscopic infarction (UtA OR 6.84 at 20-24 and 10.9 at 34-38 weeks; low BWZS OR 0.62 ), and for accelerated maturation (UtA OR 11.68 at 20-24 weeks and 18.46 at 34-38 weeks; low BWZS 0.61). Conclusion: There is considerable variability in the associations between individual features of MVM and increased UtA or UA PI and low BWZS. Although all MVM features currently carry equal weight in defining the condition of MVM, our data suggest that some should carry more weight than others. Macroscopic examination of the placenta may be helpful in identifying placental insufficiency as a small placenta and macroscopic infarction were the features most strongly associated with outcomes.