Number of buprenorphine induction attempts impacts maternal and neonatal outcomes: a multicenter cohort study.

BACKGROUND: Buprenorphine can be used to treat maternal opioid use disorder effectively and decrease obstetrical risks. Compared with the use of other medications to treat opioid use disorder, the use of buprenorphine results in improved neonatal outcomes; however, its use is associated with higher rates of treatment attrition. Initiation of buprenorphine, termed "induction," is a high-risk time for treatment dropout and can require repeated attempts. OBJECTIVE: This study aimed to evaluate the effect of multiple buprenorphine induction attempts on maternal and neonatal outcomes. STUDY DESIGN: This was a retrospective cohort study of all pregnant patients who underwent sublingual buprenorphine induction for the treatment of opioid use disorder from June 18, 2018, to January 1, 2021, at 3 tertiary care centers. Patients who required only 1 attempt for successful buprenorphine induction were compared with those who required multiple attempts but ultimately were successful in the treatment initiation during pregnancy, confirmed by urine drug screening. The primary outcome was nonprescribed opioid use at the time of delivery. The secondary outcomes included obstetrical and neonatal outcomes associated with opioid use disorder. Background characteristics were compared using Fisher exact, chi-square, Mann-Whitney U, and Student t tests. The outcomes were compared using multivariable logistic regression, and time to delivery after initiation of prenatal care was compared between groups using Kaplan-Meier curves and a Cox proportional-hazards model. RESULTS: Overall, 63 patients undergoing buprenorphine induction during pregnancy were included, with 38 (60.3%) patients with 1 attempt and 25 patients (39.7%) with multiple attempts. There was no statistical difference between the 2 groups in terms of background characteristics. Compared with a single successful attempt, multiple attempts at buprenorphine induction were associated with a significantly increased odds of nonprescribed opioid use at the time of delivery (76.0% vs 15.8%; adjusted odds ratio, 30.00; 95% confidence interval, 5.50-163.90), increased risk of preterm birth (48.0% vs 15.8%; adjusted hazard ratio, 3.24; 95% confidence interval, 1.17-8.95), and decreased rate of breastfeeding at both maternal discharge (24.0% vs 78.9%; adjusted odds ratio, 0.06; 95% confidence interval, 0.00-0.30) and infant discharge (24.0% vs 55.3%; adjusted odds ratio, 0.23; 95% confidence interval, 0.10-0.80). CONCLUSION: Requiring multiple attempts for buprenorphine induction significantly increases the odds of nonprescribed opioid use at the time of delivery and preterm birth and decreases the odds of breastfeeding. As the buprenorphine induction process may affect obstetrical outcomes for patients induced during pregnancy, investigating the techniques that increase the likelihood of successful induction is crucially needed to improve outcomes in patients with maternal opioid use disorder.

Model representations of kerogen structures: An insight from density functional theory calculations and spectroscopic measurements.

Molecular structures of kerogen control hydrocarbon production in unconventional reservoirs. Significant progress has been made in developing model representations of various kerogen structures. These models have been widely used for the prediction of gas adsorption and migration in shale matrix. However, using density functional perturbation theory (DFPT) calculations and vibrational spectroscopic measurements, we here show that a large gap may still remain between the existing model representations and actual kerogen structures, therefore calling for new model development. Using DFPT, we calculated Fourier transform infrared (FTIR) spectra for six most widely used kerogen structure models. The computed spectra were then systematically compared to the FTIR absorption spectra collected for kerogen samples isolated from Mancos, Woodford and Marcellus formations representing a wide range of kerogen origin and maturation conditions. Limited agreement between the model predictions and the measurements highlights that the existing kerogen models may still miss some key features in structural representation. A combination of DFPT calculations with spectroscopic measurements may provide a useful diagnostic tool for assessing the adequacy of a proposed structural model as well as for future model development. This approach may eventually help develop comprehensive infrared (IR)-fingerprints for tracing kerogen evolution.