Purpose
Adiponectin is a potent uterine tocolytic that decreases with gestational age, suggesting it could be a maternal metabolic quiescence factor. Maternal stress can influence preterm birth risk, and adiponectin levels may be stress-responsive. We characterized associations between adiponectin and glucocorticoids with preterm birth and modeled their predictive utility. We hypothesized maternal plasma adiponectin and cortisol are inversely related and lower adiponectin and higher cortisol associate with preterm birth.
Methods
We performed a nested case-control study using biobanked fasting maternal plasma. We included low-risk singleton pregnancies, and matched 1:3 (16 preterm, 46 term). We quantified total, high (HMW), and low molecular weight (LMW) adiponectin using ELISA. We validated an HPLC-MS/MS serum assay for use in plasma, to simultaneously measure cortisol, cortisone, and five related steroid hormones. We used linear/logistic regression to compare group means and machine learning for predictive modeling.
Results
The preterm group had lower mean LMW adiponectin (3.07 μg/mL vs. 3.81 μg/mL at 15w0d, P=0.045) and higher mean cortisone (34.4 ng/mL vs. 29.0 ng/mL at 15w0d, P=0.031). The preterm group had lower cortisol-to-cortisone and lower LMW adiponectin-to-cortisol ratios. We found HMW adiponectin, cortisol-to-cortisone ratio, cortisone, maternal height, age, and pre-pregnancy BMI most strongly predicted preterm birth (AUROC=0.8167). In secondary analyses, we assessed biomarker associations with maternal self-reported psychosocial stress. Lower perceived stress associated with a steeper change in cortisone in the term group.
Conclusion
Overall, metabolic and stress biomarkers associated with preterm birth in this healthy cohort. We identify a possible mechanistic link between maternal stress and metabolism for pregnancy maintenance.
