PP096. The effect of preterm placental calcification on uteroplacental blood flow, fetal growth and perinatal outcome in hypertension complicating pregnancy

Abstract

Introduction: Placental calcification is often found in pregnancy at term and regarded as a physiological aging process. However, its earlier presence, before 36weeks' gestation (preterm placental calcification) may have an unusual pathological implication [1-3].

Objectives: This prospective cohort study aims to examine the effect of preterm placental calcification on uteroplacental blood flow, fetal growth and perinatal death (including intrauterine fetal death and neonatal death) in hypertension complicating pregnancy.

Methods: Monthly ultrasound was performed starting at 28weeks' gestation to establish the diagnosis of Grade III placental calcification, with measurement of fetal growth and uteroplacental blood flow by Doppler velocimetry on the umbilical vessels at 34weeks' gestation. Participants (n=105) were classified into Group A (n=44), a hypertensive study group with notable preterm placental calcification at 28-36weeks' gestation, and Group B (n=61), a hypertensive control group without notable preterm placental calcification prior to 36weeks' gestation. Women who smoked or drank alcohol during their pregnancies, had multifetal gestations, or major fetal congenital anomalies were all excluded. In addition to the measurement of S/D ratio, poor uteroplacental blood flow was confirmed by absent or reversed end-diastolic velocity (AREDV). Logistic regression analysis was used to estimate the risks of AREDV, poor fetal growth (IUGR) and perinatal death by calculating odds ratios (OR) and 95% confidence intervals (CI), adjusted by maternal age, body mass index, economic status, co-morbidities (e.g. diabetes, marked anemia and placenta previa), type of delivery, and parity.

Results: In Group A, there is significant higher mean S/D ratio (3.80 Vs 3.28), as well as higher incidences of AREDV (28.2% Vs 10.5%), IUGR (45.5% Vs 26.2%), and perinatal deaths (20.5% Vs 6.6%) than those in Group B (p<0.05). The risks of AREDV (OR 3.28; 95%CI 1.04-10.37), IUGR (OR 3.24; 95%CI 1.26-8.29), and perinatal death (OR 4.78; 95%CI 1.23-18.67) were greater in Group A than those in Group B (the control group).

Conclusion: In hypertension complicating pregnancy, the presence of preterm placental calcification is associated with a higher incidence of poor uteroplacental blood flow, fetal growth and perinatal death. Being an ominous sign, it may precede poor uteroplacental blood flow, fetal growth and adverse fetal outcome and can serve as a predictor of such findings when noted on ultrasonography. The affected baby is at greater risk, thus requiring closer antepartum surveillance for fetal well-being.