Perinatal Outcome with Sonographically Thin Placentas

Abstract

In order to determine the incidence and significance of sonographically thin placentas, we reviewed the computerized records of 18,937 viable, singleton pregnancies. Of these, 0.6% had thin placentas diagnosed by ultrasound examination with a mean thickness of 16 ± 4 mm in the second and 20 ± 3 mm in the third trimester. At the time of the first ultrasound diagnosis of a thin placenta, 22.2% had polyhydramnios, and 1.8% had oligohydramnios. When the thin placenta cohort without polyhydramnios was compared to controls, there was a significantly increased incidence of perinatal mortality, odds ratio = 2.9, 95% confidence limits (CL) = 1.2 to 7.3; neonatal intensive care unit admissions, odds ratio = 2.2, CL = 1.3 to 3.7; and birth weight below the 10th percentile, odds ratio = 2.8, CL = 1.7 to 4.7. The finding of a thin placenta by ultrasound should alert the clinician to the possibility of compromised perinatal outcome.

Key Words:

• Ultrasound
• Thin placenta
• Polyhydramnios