Ultrasound assessment of placental function: the effectiveness of placental biometry in a low-risk population as a predictor of a small for gestational age neonate

Prenatal Diagnosis, 05/02/2012

Authors have provided reference ranges for placental length and thickness from 18 to 24 weeks' gestation. A single measurement of placental length incorporated into the anatomy scan may assist in the early detection of a group at risk of delivering an SGA neonate.


  • Placental length and thickness were measured by two sonographers in 520 singleton pregnancies.
  • Uterine artery Doppler studies and a placental morphological assessment were also performed.
  • Placental size was correlated with the birthweight centiles at delivery.


  • A placental length <10th centile between the gestational age of 18 and 24 weeks is a significant factor associated with SGA neonate [odds ratio (OR)=2.8, 95% CL, 1.1–6.9].
  • An abnormal uterine artery Doppler is a significant factor for SGA neonate (OR=3.4, 95% CL, 1.6–7.4).
  • There was a weak relationship between cord insertion <2 cm from the placental margin and an SGA neonate (OR=1.8, 95% CL, 0.4–8.2).

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