RESUMEN
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.
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This commentary is in response to the Call for Papers put forth by the Critical Midwifery Studies Collective (June 2022). We argue that due to a long and ongoing history of gendered racism, Women of Color are devalued in U.S. society. Devaluing Women of Color leads maternal healthcare practitioners to miss and even dismiss distress in Women of Color. The result is systematic underdiagnosis, undertreatment, and the delivery of poorer care to Women of Color, which negatively affects reproductive outcomes generally and birth outcomes specifically. These compounding effects exacerbate distress in Women of Color leading to greater distress. Stress physiology is ancient and intricately interwoven with healthy pregnancy physiology, and this relationship is a highly conserved reproductive strategy. Thus, where there is disproportionate or excess stress (distress), unsurprisingly, there are disproportionate and excess rates of poorer reproductive outcomes. Stress physiology and reproductive physiology collide with social injustices (i.e., racism, discrimination, and anti-Blackness), resulting in pernicious racialized maternal health disparities. Accordingly, the interplay between stress and reproduction is a key social justice issue and an important site for theoretical inquiry and birth equity efforts. Fortunately, both stress physiology and pregnancy physiology are highly plastic-responsive to the benefits of increased social support and respectful maternity care. Justice means valuing Women of Color and valuing their right to have a healthy, respected, and safe life.