Does Maternal Asthma Modify the Association Between Placental Hormones and Placental Weight? [ID 2683539]

INTRODUCTION: Placental endocrine function is essential for placental growth. Maternal asthma may alter placental growth. The relationship between asthma, placental hormones, and placental size remains understudied. We examined the association between placental hormones and placental weight in pregnant participants with and without asthma. METHODS: Hormones influencing placenta function, prolactin (in nanograms per milliliter), lactogen (in nanograms per milliliter), placenta growth hormone (PGH) (in picograms per milliliter), IGF-1 (in picograms per milliliter), and IGF-2 (in nanograms per milliliter), were measured from serum drawn at ∼30 weeks (range, 27–36 weeks) of gestation, categorized into quartiles. Placental weight (in grams) was obtained from placental pathology reports. Data were available for 174 women (134 with asthma; 40 without) from the B-WELL-Mom study. Linear regression models estimated associations between placental hormones and placental weight, adjusted for maternal factors. Models were fit overall, and asthma*hormone interaction terms were fit. We then stratified models by asthma. This analysis was approved by the authors’ home institution IRB. RESULTS: Participants were, on average, 31 years old, had high income (47%; >$140,000), and were racially diverse (40% White, 40% Black, 15% Hispanic, 5% mixed race). Mean placental weight (overall, 465.56 g) differed between those with (473.43 g) and without asthma (439.20 g; P<.05). Placental hormone levels also varied by asthma status. In overall regression analyses, high levels of PGH (quartile 4 versus quartile 1) were associated with increased placental weight (68.32 g; 95% CI, 24.23, 112.40). The association between high levels of PGH and placental weight was stronger among women without asthma (127.47 g; 95% CI, 19.22, 235.72) than among those with asthma (66.18 g; 95% CI, 16.33, 116.03; P-interaction=.12). CONCLUSION: Our findings suggest the association between PGH and placental weight differs by asthma status. Additional research regarding placental function among women with asthma is warranted to better understand adverse outcomes among pregnancies complicated by asthma.