Browsing by Author "Silva, Larissa L."

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    Do maternal demographics and prenatal history impact the efficacy of betamethasone therapy for threatened preterm labor?
    (BMC, 2021-06-24) Kinney, Mary T.; Quinney, Sara K.; Trussell, Hayley K.; Silva, Larissa L.; Ibrahim, Sherrine A.; Haas, David M.; Obstetrics and Gynecology, School of Medicine
    Background: Betamethasone (BMZ) is used to accelerate fetal lung maturation in women with threatened preterm birth, but its efficacy is variable and limited by the lack of patient individualization in its dosing and administration. To determine sources of variability and potential opportunities for individualization of therapy, the objective of this study was to evaluate maternal factors associated with development of neonatal respiratory distress syndrome (RDS) in a cohort of women who received betamethasone. Methods: This study prospectively enrolled women, gestational ages 23-34 weeks, who received betamethasone for threatened preterm birth. Maternal demographics, prenatal history, and neonatal outcomes were abstracted from hospital records. RDS was the primary outcome. Associations between RDS diagnosis and maternal demographics, prenatal history, and betamethasone dosing were evaluated in a case-control analysis and multivariable regression adjusted for gestational age at delivery. Secondary analyses limited the cohort to women who delivered within 1 or 2 weeks of betamethasone dosing. Results: Of 209 deliveries, 90 (43 %) resulted in neonatal RDS. Within the overall cohort and controlling for gestational age at birth, RDS was only associated with cesarean births compared to vaginal births (adjusted OR 1.17 [1.06-1.29]). Route of delivery was also the only significant factor related to RDS in the 83 neonates delivered within 7 days of BMZ dosing. However, among 101 deliveries within 14 days of betamethasone dosing and controlling for gestational age at birth, women who experienced preterm premature rupture of membranes (PPROM) had lower RDS rates than those without PPROM (57.9 % vs. 80.2 %, adjusted OR 0.81 [0.67-0.99]). Maternal age, BMI, race, and ethnicity were not associated with RDS in the regression models. Conclusions: Of maternal characteristics analyzed, only delivery by cesarean was associated with neonatal RDS after antenatal betamethasone use.
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    Physiologically based pharmacokinetic modelling in pregnancy: Model reproducibility and external validation
    (Wiley, 2021-08) Silva, Larissa L.; Silvola, Rebecca M.; Haas, David M.; Quinney, Sara K.; Medicine, School of Medicine
    Aims Physiologically based pharmacokinetic (PBPK) models have been previously developed for betamethasone and buprenorphine for pregnant women. The goal of this work was to replicate and reassess these models using data from recently completed studies. Methods Betamethasone and buprenorphine PBPK models were developed in Simcyp V19 based on prior publications using V17 and V15. Ability to replicate models was verified by comparing predictions in V19 to those previously published. Once replication was verified, models were reassessed by comparing predictions to observed data from additional studies in pregnant women. Model performance was based upon visual inspection of concentration vs. time profiles, and comparison of pharmacokinetic parameters. Models were deemed reproducible if parameter estimates were within 10% of previously reported values. External validations were considered acceptable if the predicted area under the concentration–time curve (AUC) and peak plasma concentration fell within 2-fold of the observed. Results The betamethasone model was successfully replicated using Simcyp V19, with ratios of reported (V17) to reproduced (V19) peak plasma concentration of 0.98–1.04 and AUC of 0.95–1.07. The model-predicted AUC ratios ranged from 0.98–1.79 compared to external data. The previously published buprenorphine PBPK model was not reproducible, as we predicted intravenous clearance of 70% that reported previously (both in Simcyp V15). Conclusion While high interstudy variability was observed in the newly available clinical data, the PBPK model sufficiently predicted changes in betamethasone exposure across gestation. Model reproducibility and reassessment with external data are important for the advancement of the discipline. PBPK modelling publications should contain sufficient detail and clarity to enable reproducibility.