Background: This study was conducted to  delineate a standard nomogram for fetal adrenal gland dimensions in an Indian cohort and to examine the relationship between fetal adrenal gland and kidney lengths.

Methods: Prior to the commencement of the study, approval was sought from the ethical committee, and informed consent was acquired from 123 expectant mothers attending the VIMS & RC's Radio-diagnosis department between 18 and 37 weeks of gestation. These participants underwent ultrasonography using a curvilinear transducer 2-6 MHz on a Philips Affiniti 50G machine. Sagittal and coronal views were used to record the maximum dimensions of both adrenal glands. Thereby, a reference range for the adrenal gland size during the second and third trimesters was deduced.

Results: During 18-24 weeks, measurements for the right adrenal gland were: medial limb (1.01 * 0.51), body (0.16 * 0.35), lateral limb (1.02 * 0.51), with a concurrent kidney size of 19.16± 1.95 mm. For the left adrenal gland: medial limb (1.01 * 0.49), body (0.16 * 0.34), lateral limb (1.01 * 0.5), and kidney size 19.8± 1.52 mm.For 25-30 weeks, right adrenal gland measurements were: medial limb (1.08 * 0.5cm), body (1.34 * 0.65cm), lateral limb (1.79 * 0.8cm), with kidney size being 25.83± 1.64 mm. The left adrenal gland revealed medial limb (1.08 * 0.81cm), body (1.34 * 0.65cm), lateral limb (1.8 * 0.8cm), and kidney size at 26.07± 1.46 mm.From 31-35 weeks, the right adrenal gland dimensions were: medial limb (2.34 * 1.13cm), body (1.75 * 0.85cm), lateral limb (2.29 * 1.1cm), and kidney size at 31.57± 0.67 mm. The left adrenal gland showed medial limb (2.3 * 1.04cm), body (1.8 * 0.86cm), lateral limb (2.34 * 1.19cm), and kidney size at 32.03± 2.45 mm. Lastly, between 36-40 weeks, the right adrenal gland measurements were: medial limb (2.61 * 1.31cm), body (2.32 * 1.06cm), lateral limb (2.58 * 1.27cm), and kidney size was 35.36± 1.61 mm. The left adrenal gland had medial limb (2.6 * 1.3cm), body (2.33 * 1.07cm), lateral limb (2.6 * 1.32cm), with a kidney size of 35.33± 1.51 mm.

Conclusion: he study, a cross-sectional analysis conducted in the Radio-diagnosis department at Vydehi Institute of Medical Sciences and Research Centre, Bangalore, successfully established a standard nomogram for fetal adrenal gland dimensions in an Indian cohort during the second and third trimesters. Additionally, the established fetal renal to adrenal ratio validated and enriched the derived data.