Opioid poisoning during pregnancy: prevalence, characteristics, and neonatal outcomes.

While it has been postulated that opioid poisoning during pregnancy may cause adverse maternal and neonatal outcomes, the harm associated with opioid poisoning during pregnancy has not been robustly examined. Pregnant women admitted to hospital or presenting to the emergency department (ED) in Western Australia (WA) with a diagnosis of opioid poisoning were identified by linking state midwifery records with hospital and ED administrative data. Maternal and neonatal outcomes were compared with opioid poisoning that occurred in the 12 months prior to conception or the 12 months following birth. Between 2003 and 2018, 57 neonates were born to women who had experienced opioid poisoning during pregnancy (14.1 per 100,000 births) in WA. The incidence of opioid poisoning in the year prior to pregnancy (IRR: 3.04, 95%CI: 2.30, 4.02) and the year following pregnancy (IRR: 1.96, 95%CI: 1.46, 2.64) was significantly higher than during pregnancy. Opioid poisoning during pregnancy was less likely to involve multiple substances and be intentional (rather than accidental). Neonatal conditions associated with in utero hypoxia were significantly less common in neonates born to women who experience opioid poisoning prior to pregnancy compared with during pregnancy (OR: 0.17, 95%CI: 0.04, 0.80). Opioid poisoning in pregnancy was not associated with an increased risk of other serious adverse neonatal outcomes. Opioid poisoning during pregnancy is uncommon and less likely to be intentional and involve multiple substances. Opioid poisoning during pregnancy is likely associated with an increased risk of conditions associated with in utero hypoxia.

Prevalence and Perinatal Outcomes Following In Utero Exposure to Prehospital Emergency Methoxyflurane: A 17-Year Retrospective Cohort Study.

OBJECTIVE: To examine the prevalence of exposure and perinatal outcomes associated with in utero exposure to methoxyflurane. DESIGN, SETTING AND POPULATION: Whole-population ambulance data in Western Australia (WA) were linked to the statutory perinatal data collection to identify pregnant women transferred by ambulance between 2000 and 2016. The proportion of neonates in WA exposed to methoxyflurane, fentanyl or no analgesia during an ambulance transfer was calculated. Perinatal outcomes of pregnancies exposed to methoxyflurane (n=1579) were compared to those exposed to fentanyl (n=203) or no analgesia (n=10524) using multivariable logistic regression modelling. Perinatal outcomes were considered overall and by trimester of exposure. MAIN OUTCOME MEASURES: Primary outcomes were the prevalence of in utero methoxyflurane exposure and Apgar score on the day of delivery. RESULTS: In the study period, 0.4% of all neonates born in WA were exposed to methoxyflurane in utero. Methoxyflurane exposure on the day of delivery (n=657) was not associated with an increased likelihood of a low Apgar score at five minutes compared with no analgesia (n=2667) (OR 1.23, 95% CI 0.91-1.67). Whereas fentanyl exposure (n=22) was associated with an increased likelihood of low Apgar score compared with methoxyflurane (OR 3.67, 95% CI 1.18-11.48). CONCLUSIONS: Methoxyflurane is commonly used by ambulance services to treat pain in pregnant women in WA. While not recommended for use in pregnancy, pregnancies exposed to methoxyflurane did not have an increased risk of adverse perinatal outcomes in this study.