Characteristics of Individuals in the United States Who Used Opioids During Pregnancy

Performance of Phenotype Algorithms for the Identification of Opioid-Exposed Infants

OBJECTIVE

Observational studies examining outcomes among opioid-exposed infants are limited by phenotype algorithms that may under identify opioid-exposed infants without neonatal opioid withdrawal syndrome (NOWS). We developed and validated the performance of different phenotype algorithms to identify opioid-exposed infants using electronic health record data.

METHODS

We developed phenotype algorithms for the identification of opioid-exposed infants among a population of birthing person-infant dyads from an academic health care system (2010-2022). We derived phenotype algorithms from combinations of 6 unique indicators of in utero opioid exposure, including those from the infant record (NOWS or opioid-exposure diagnosis, positive toxicology) and birthing person record (opioid use disorder diagnosis, opioid drug exposure record, opioid listed on medication reconciliation, positive toxicology). We determined the positive predictive value (PPV) and 95% confidence interval for each phenotype algorithm using medical record review as the gold standard.

RESULTS

Among 41 047 dyads meeting exclusion criteria, we identified 1558 infants (3.80%) with evidence of at least 1 indicator for opioid exposure and 32 (0.08%) meeting all 6 indicators of the phenotype algorithm. Among the sample of dyads randomly selected for review (n = 600), the PPV for the phenotype requiring only a single indicator was 95.4% (confidence interval: 93.3-96.8) with varying PPVs for the other phenotype algorithms derived from a combination of infant and birthing person indicators (PPV range: 95.4-100.0).

CONCLUSIONS

Opioid-exposed infants can be accurately identified using electronic health record data. Our publicly available phenotype algorithms can be used to conduct research examining outcomes among opioid-exposed infants with and without NOWS.

Maternal opioid use disorder and infant mortality in Wisconsin, United States, 2010-2018

OBJECTIVE

The difference in infant health outcomes by maternal opioid use disorder (OUD) status is understudied. We measured the association between maternal OUD during pregnancy and infant mortality and investigated whether this association differs by infant neonatal opioid withdrawal syndrome (NOWS) or maternal receipt of medication for OUD (MOUD) during pregnancy.

METHODS

We sampled 204,543 Medicaid-paid births from Wisconsin, United States (2010-2018). The primary exposure was any maternal OUD during pregnancy. We also stratified this exposure on NOWS diagnosis (no OUD; OUD without NOWS; OUD with NOWS) and on maternal MOUD receipt (no OUD; OUD without MOUD; OUD with <90 consecutive days of MOUD; OUD with 90+ consecutive days of MOUD). Our outcome was infant mortality (death at age <365 days). Demographic-adjusted logistic regressions measured associations with odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Maternal OUD was associated with increased odds of infant mortality (OR 1.43; 95% CI 1.02-2.02). After excluding infants who died <5 days post-birth (i.e., before the clinical presentation of NOWS), regression estimates of infant mortality did not significantly differ by NOWS diagnosis. Likewise, regression estimates did not significantly differ by maternal MOUD receipt in the full sample.

CONCLUSIONS

Maternal OUD is associated with an elevated risk of infant mortality without evidence of modification by NOWS nor by maternal MOUD treatment. Future research should investigate potential mechanisms linking maternal OUD, NOWS, MOUD treatment, and infant mortality to better inform clinical intervention.

Effect of prenatal and early post-natal oxycodone exposure on the reinforcing and antinociceptive effects of oxycodone in adult C57BL/6 J mice

Abuse of opioids (mu-opioid agonists such as oxycodone) among parents during the gestation and early post-natal period is a concern for the long-term health of the offspring, beyond potential neonatal withdrawal symptoms. However, there is only limited information on such effects.

OBJECTIVES

We examined how prenatal, and early-post natal oxycodone exposure affected opioid addiction behaviors.

METHODS

Adult male and female C57BL/CJ mice housed separately were first injected with ascending doses of oxycodone 1 time/day (1 mg/kg × 10 days, 1.5 mg/kg × 10 days, 2 mg/kg × 10 days, s.c.) whereas control mice were injected with saline. Newly formed parental dyads were then housed together and continued to receive ascending doses of oxycodone (3 mg/kg × 10 days, 4 mg/kg × 10 days, 5 mg/kg × 10 days, 6 mg/kg × 10 days or saline, s.c.) or saline during mating and gestation until the birth of the litter. The dams continued to receive oxycodone or saline through lactation, until F1 offspring were weaned. Upon reaching adulthood (12 weeks of age), male and female F1 offspring were examined in intravenous self-administration (IVSA) of oxycodone, on oxycodone-induced conditioned place preference (CPP) and oxycodone-induced antinociception.

RESULTS

Adult F1 male and female offspring of parental dyads exposed to oxycodone self-administered more oxycodone, compared to offspring of control parental dyads. Ventral and dorsal striatal mRNA levels of genes such as Fkbp5 and Oprm1 were altered following oxycodone self-administration.

CONCLUSION

Prenatal and early post-natal oxycodone exposure enhanced oxycodone self-administration during adulthood in the C57BL/6 J mice.

Opioid, methamphetamine, and polysubstance use: perinatal outcomes for the mother and infant

The escalation in opioid pain relief (OPR) medications, heroin and fentanyl, has led to an increased use during pregnancy and a public health crisis. Methamphetamine use in women of childbearing age has now eclipsed the use of cocaine and other stimulants globally. Recent reports have shown increases in methamphetamine are selective to opioid use, particularly in rural regions in the US. This report compares the extent of our knowledge of the perinatal outcomes of OPRs, heroin, fentanyl, two long-acting substances used in the treatment of opioid use disorders (buprenorphine and methadone), and methamphetamine. The methodological limitations of the current research are examined, and two important initiatives that will address these limitations are reviewed. Current knowledge of the perinatal effects of short-acting opioids, OPRs, heroin, and fentanyl, is scarce. Most of what we know about the perinatal effects of opioids comes from research on the long-acting opioid agonist drugs used in the treatment of OUDs, methadone and buprenorphine. Both have better perinatal outcomes for the mother and newborn than heroin, but the uptake of these opioid substitution programs is poor (<50%). Current research on perinatal outcomes of methamphetamine is limited to retrospective epidemiological studies, chart reviews, one study from a treatment center in Hawaii, and the US and NZ cross-cultural infant Development, Environment And Lifestyle IDEAL studies. Characteristics of pregnant individuals in both opioid and MA studies were associated with poor maternal health, higher rates of mental illness, trauma, and poverty. Infant outcomes that differed between opioid and MA exposure included variations in neurobehavior at birth which could complicate the diagnosis and treatment of neonatal opioid withdrawal (NOWs). Given the complexity of OUDs in pregnant individuals and the increasing co-use of these opioids with MA, large studies are needed. These studies need to address the many confounders to perinatal outcomes and employ neurodevelopmental markers at birth that can help predict long-term neurodevelopmental outcomes. Two US initiatives that can provide critical research and treatment answers to this public health crisis are the US Environmental influences on Child Health Outcomes (ECHO) program and the Medication for Opioid Use Disorder During Pregnancy Network (MAT-LINK).

The impact of opioids on the transcriptional landscape of human villous trophoblasts

INTRODUCTION

Opioid use disorder (OUD) is implicated in major obstetrical diseases such as fetal growth restriction. Whether or not opioids directly impact placental trophoblast development and function remains unclear. We sought to examine the expression of opioid receptors (OPRs) in villous trophoblasts and the effect of opioids on placental transcriptomics.

METHODS

Trophoblast stem (TS) cells and primary human trophoblast (PHT) cells from healthy term placentas were used to assess OPR expression in conditions that enhance trophoblast stemness vs differentiation. Placental RNAseq was conducted using our retrospective cohorts of pregnant people with OUD vs controls, both without major obstetrical complications. RT-qPCR was used to determine the effect of fentanyl on the expression of putative opioid targets and stemness or differentiation-associated genes in TS and PHT cells.

RESULTS

Three main OPRs, including OPRM1, OPRD1, and OPRK1 were expressed in term PHT cells cultured in the stemness medium, whereas only OPRD1 and OPRK1 were expressed in TS cells. Interestingly, upon induction of differentiation, the expressed OPR mRNAs in TS or in PHT cells were downregulated. We found 286 differentially expressed long RNAs in placentas from the OUD participants vs controls. While three putative opioid targets differed their expression in stemness vs differentiation states of trophoblasts, fentanyl had no effect on their expression or the expression of major stemness or differentiation-relevant genes in TS and PHT cells.

DISCUSSION

Trophoblastic expression of OPRs and opioid RNA targets is impacted by cell differentiation, suggesting differential susceptibility of villous trophoblasts to the effect of opioids.