Correlation Between Ultrasonographic Placental Thickness and Adverse Fetal and Neonatal Outcomes

Introduction The placenta is often overlooked in the routine evaluation of normal gestations, receiving attention only when abnormalities are detected. Placental thickness can serve as a good predictor of fetal growth and birth weight, especially in the second trimester. In this prospective study, we measured placental thickness in the second and third trimesters of singleton pregnancies and identified an association between placental thickness and adverse outcomes such as congenital anomalies, fetal growth restriction (FGR), prematurity, low birth weight, stillbirth, and hydrops fetalis. Methodology A total of 298 patients aged 20 to 33 years with a singleton pregnancy and regular cycles, who were sure of the date of their last menstrual period, were observed. Placental thickness was measured by ultrasound at 18-20 and 30-32 weeks, and patients were divided into three groups. Group A consisted of patients with normal placental thickness. Group B included patients with a thin placenta (below the 10th percentile). Group C consisted of patients with a thick placenta (above the 95th percentile). The correlation between placental thickness and the fetal and neonatal outcome was observed. Results Out of 298 patients, 82 (27.5%) were primigravida and 216 (72.4%) were multigravida. At 18-20 weeks, premature birth was observed in one patient (7.69%) in Group C and six patients (20%) in Group B, compared with eight patients (3.14%) in Group A. At 30-32 weeks, premature birth was seen in two patients (16.67%) in Group C and 11 patients (36.67%) in Group B, compared with two patients (0.78%) in Group A. At 18-20 weeks of gestation, low birth weight was observed for three patients (23.08%) in Group C and 16 patients (53.33%) in Group B, compared with 15 patients (5.88%) in Group A. At 30-32 weeks, low birth weight was observed for four patients (33.33%) in Group C and 19 patients (63.33%) in Group B compared with 11 patients (4.30%) in Group A. A significant association was found between a thin placenta and low birth weight and prematurity at both 18-20 and 30-32 weeks of gestation. Two patients (13.33%) had major congenital abnormalities and a thick placenta at 18-20 weeks. In Group C, hydrops were observed in two patients (15.38%) at 18-20 weeks and two patients (16.67%) at 30-32 weeks. A significant association was found between a thick placenta and hydrops. At 30-32 weeks, 13 patients (43.33%) in Group B had developed FGR compared with six patients (2.34%) with a normal placenta. A significant association was found between a thin placenta and FGR. One patient (7.69%) with a thick placenta had a stillbirth, indicating a nonsignificant association. Conclusions A positive correlation was observed between congenital anomalies and hydrops and a thick placenta, whereas FGR, preterm labor, prematurity, and low birth weight were associated with a thin placenta. Subnormal placental thickness for a particular gestational age may be the earliest sign of FGR. A sonographically identified abnormal placenta should alert clinicians to the possibility of a compromised perinatal outcome and the need for evaluation and close follow-up.