Background: The human foetal adrenal (FA) undergoes vast physiological changes as pregnancy progresses. Original descriptions of FA development emerged following morphometric studies from spontaneous/medical terminations. These revealed the greatest increase in FA size was during the first trimester. Recently, sonographic evaluation of human FA volume and length has led to the creation of normal FA growth centiles and correlations between FA size and estimated foetal weight (EFW). These studies are limited by single time-point observations or single-plane measurements.
Aim: To characterise normal human FA growth by performing the first serial 3-dimensional ultrasonographic studies of FA volume during the 2nd and 3rd trimesters of pregnancy.
Methods: A prospective longitudinal study of 33 foetuses was undertaken. Serial 3-dimensional transabdominal ultrasound measurements (Voluson-730 and -E8 systems; 48 MHz array transducer) of FA volume and foetal biometry were performed at gestational age (GA) ~20/40 weeks, 28/40 weeks, 34/40 weeks and 38/40 weeks. FA volume was calculated using Virtual Organ Computer-aided Analysis software. Women were followed until the outcome of pregnancy was known.
Results: A linear correlation between FA volume and EFW was observed (r=0.6290, P<0.0001). The mean adrenal growth velocity was 0.097 cm3/week between GA 2028/40, 0.034 cm3/week between GA 2834/40 weeks, and 0.447 cm3/week between GA 3438/40 weeks. An increase in 3rd trimester FA growth velocity has not previously been reported.
|GA (weeks) (mean±S.D.)||FA volume (cm) (mean±S.D.)||EFW (g) (mean±S.D.)|
Conclusion: Serial 3-dimensional ultrasonography of FA volumes during the 2nd−3rd trimesters of pregnancy provides detailed normative data. The observed increase in FA growth velocity as pregnancy nears completion is interesting, and suggests novel functional implications in terms of steroid production, and a potential role for the FA in the onset of parturition.
Funding: This work was supported by the Joan Adams Fellowship (grant number NDM9050B) and Rosetrees Charity (grant number M296).
01 - 03 Oct 2015
European Society for Paediatric Endocrinology