Reproduction Abstracts

Introduction: Both obesity and mood disorders associate with altered glucocorticoid (GC) secretion and action. During pregnancy placenta regulates foetal exposure to maternal GC through enzymatic clearance (HSD-2) and retrograde transfer (ABC transporters). We and others have shown that maternal obesity and/or mood disorders alter placental HSD-2 mRNA level. We therefore hypothesised that placental ABC transporter gene expression is also altered, and investigated this using samples from obese and lean women with mood assessments in pregnancy.

Materials and methods: We administered General Health Questionnaire (GHQ) twice during pregnancy to evaluate mood in 135 lean and 222 severely obese (SO) women (BMI 22.77±S.D. 1.65 vs 44.20±4.10 kg/m², P≤0.0001). Placental ABC transporters (ABCB1, ABCC1, and ABCG2) mRNA levels were measured by QPCR against housekeeping genes (YWHAZ, TBP) in a subset of placental samples (lean n=19, SO n=24).

Results and discussion: SO mothers had higher GHQ scores (indicating more depressive symptoms) than lean (mean difference (S.D.) +1.613 (0.302), P≤0.0001). ABC transporters mRNA levels were similar in SO and lean. ABCC1 gene expression, but not ABCB1 or ABCG2, correlated negatively with GHQ scores in early (ρ=−0.442, P=0.016) and late pregnancy (ρ=−0.369, P=0.038). Therefore placental GC transporters do not seem to regulate foetal GC exposure in obese pregnancies. However as ABCC1 pumps GC to foetal circulation whilst ABCB1 and ABCG2 pumps GC back to maternal circulation, these findings suggest a placental protective mechanism from maternal GC in women with depressive symptoms during pregnancy.