Maternal serum sex hormone–binding globulin and androgen levels in fetuses with intrauterine growth restriction: a prospective case–control study

PURPOSE: To compare maternal serum sex hormone-binding globulin (SHBG) and androgen markers in intrauterine growth restriction (IUGR) and gestational-age-matched controls, and to assess their associations with fetal growth. METHODS: This prospective case-control study included 45 IUGR pregnancies and 50 controls. Blood was collected in the late third trimester, preferentially antepartum; otherwise within 24 h postpartum (IUGR: 36/45 antepartum, 9/45 postpartum; controls: 9/50 antepartum, 41/50 postpartum). Total testosterone, dehydroepiandrosterone sulfate, estradiol, androstenedione, and SHBG were measured by immunoassay. FAI was calculated as (testosterone nmol/L/SHBG nmol/L) × 100 after conversion of testosterone from ng/mL to nmol/L. Sensitivity analyses compared hormone levels within antepartum and postpartum subgroups. Exploratory multivariable linear regression in the IUGR group assessed whether SHBG and total testosterone were independently associated with birth weight percentile and abdominal circumference percentile after adjustment for maternal age, systolic blood pressure, and sampling time. RESULTS: IUGR mothers were older, delivered earlier, and had higher systolic blood pressure than controls. Birth weight was lower in IUGR (2190 ± 624 g vs 3306 ± 391 g). SHBG was lower in IUGR (257 ± 117 vs 382 ± 106 nmol/L, p < 0.001), whereas FAI was modestly higher (1.27 ± 1.06 vs 0.85 ± 0.71, p = 0.018). In the antepartum-only subgroup, SHBG remained lower in IUGR, whereas FAI did not differ significantly. Unadjusted correlations of SHBG and total testosterone with fetal growth parameters in IUGR were attenuated after adjustment. CONCLUSION: IUGR was associated with lower maternal SHBG. The FAI difference was modest and not robust in the antepartum-only analysis. Hormone-growth associations were exploratory and were not independently significant after adjustment.