Placental Growth during Normal Pregnancy - A Magnetic Resonance Imaging Study

Gynecol Obstet Invest. 2017;82(5):462-467. doi: 10.1159/000452661. Epub 2016 Dec 14.


Objective: To investigate normal human placental growth longitudinally throughout the second and third trimesters using MRI.

Methods: Twenty normal, first-time singleton pregnancies were scanned 7 times between the 14th and 38th week of gestation, at 4-week intervals, using MRI. Placental volumes were measured in both sagittal and transversal slices. All placentas were weighed after delivery to make a comparative study.

Results: Sixteen of the 20 women had increasing placental volumes from the 14th to 38th week of gestation. The 6th and 7th scan showed that 4 women had placentas of the same size. The mean placental volume increases linearly from the 14th till the 38th week of gestation, with a constant mean growth rate of 29.97 ml/week. The median placental volume extrapolated to delivery was to 856 ml (range 602-1,050 ml). The median weight of the exsanguinated placenta after delivery was 640 g (range 500-787 g). All pregnancies were carried to term, resulting in the delivery of healthy infants with good correlation between placental size and birth weight (R = 0.56, p = 0.009).

Conclusion: Placental growth was measured systematically in a longitudinal study through the second and third trimesters using MRI. MRI provides a safe and feasible method to measure placental growth. The mean placental growth was linear throughout the second and third trimesters.

Keywords: MRI; Obstetric; Placenta; Pregnancy.

MeSH terms

  • Adult
  • Birth Weight
  • Female
  • Gestational Age
  • Humans
  • Longitudinal Studies
  • Magnetic Resonance Imaging*
  • Parturition
  • Placenta / diagnostic imaging*
  • Placenta / physiology*
  • Pregnancy
  • Pregnancy Trimester, Second
  • Pregnancy Trimester, Third