Objective: Brown and white adipose tissues in different fetal regions undergo distinct developmental processes. This study aimed to quantitatively evaluate the fetal adipose tissue development of singleton fetuses. Methods: A total of 42 non-diabetic singleton pregnancies across 28 and 38 gestational weeks (GW) were enrolled. Multi-echo water-fat separation (IDEAL-IQ) was performed and proton density fat fraction (PDFF) and apparent transverse relaxation rate (R2*) values were measured for multiple anatomical regions, including cheeks, occiput, underjaw , neck, back, thorax, abdomen, and thighs. Correlations with gestational age were analyzed, and analysis of covariance (ANCOVA) was conducted by grouping participants into early (28–31 GW), mid (32–34 GW), and late (35–38 GW) gestational stages. Results: PDFF values in all fetal regions showed significant positive correlations with gestational age (p