Area of Wharton's jelly as an estimate of the thickness of the umbilical cord and its relationship with estimated fetal weight

BACKGROUND: To build a reference curve for the area of Wharton's jelly (WJ) in low-risk pregnancies from 13 to 40 weeks and to assess its relationship with estimated fetal weight (EFW). METHODS: 2,189 low-risk pregnancies had the area of WJ estimated by ultrasound and the 10(th), 50(th )and 90(th )percentiles calculated using a third-degree polynomial regression procedure. EFW by ultrasound was correlated with the measurement of the area of WJ. RESULTS: The area of WJ increased according to gestational age (R(2 )= 0.64), stabilizing from the 32(nd )week onwards. There was a significant linear correlation between area of WJ and EFW up to 26 weeks (R = 0.782) and after that 5t remained practically constant (R = 0.047). CONCLUSION: The area of WJ increases according to gestational age, with a trend to stabilize at around 32 weeks of gestation. It is also linearly correlated with EFW only up to 26 weeks of gestation.