In a recent study, researchers looked at the rising nationwide trend of opioid abuse and dependence in pregnancy and obstetrical outcomes in this patient population. Previous research has focused on neonatal outcomes, such as neonatal abstinence syndrome; however, maternal complications have not been well-studied. In this study, data was collected from the Nationwide Inpatient Sample (NIS), including nearly 57 million American women who were admitted for obstetric delivery between the years 1998-2011. Overall 113,105 of those women (0.2%) were identified as abusing or being dependent on opioids. The prevalence increased by 127% from the beginning of the study in 1998 until its completion in 2011, reflecting the growing opioid epidemic. The increase was mostly represented in women 20 to 34 years or age.
Obstetrical outcomes were pooled from the last 5 years of the dataset, 2007-2011, (n = 20,517,479) so as to best reflect the recent changes in obstetrical practices, including increasing rates of cesarean delivery, labor inductions, and use of regional anesthesia.
The authors found that opioid abuse or dependence during pregnancy (n= 60,994) markedly increased the odds of obstetrical mortality. Opioid abuse or dependence was associated with a 4.6-fold increase risk of maternal death during hospitalization and was present in 1.5% of all deliveries complicated by maternal death. The authors hypothesized that while these women are often more tolerant to analgesia and often require higher doses of opioids to treat postpartum pain, they remain vulnerable to the sedative effects of analgesics which can result in respiratory compromise, particularly when combined with other synergistic medications.
The following obstetrical complications were more common in women using opioids during pregnancy: maternal cardiac arrest, intrauterine growth restriction, placental abruption, preterm labor, stillbirth, premature rupture of membranes, need for transfusion, oligohydramnios, and longer length of hospital stay. Opioid use was also associated with increased odds of cesarean delivery and anesthesia complications. Conversely, the risk of preeclampsia/eclampsia was significantly lower in this population. When the researchers compared opioid use to other non-opioid use disorders in pregnancy, increased odds remained for IUGR, length of stay >7 days, preterm delivery, oligohydramnios, need for transfusion, and cesarean delivery.
The study had several limitations. The researchers were unable to differentiate between those who were abusing or dependent on prescription pain killers, those using heroin or other illicit opioids, and those who were enrolled in opioid maintenance programs (buprenorphine and methadone assisted treatment). They were also unable to control for the timing of fetal exposure, the amount of opioid used, or different classes of opioids.
Despite these limitations, this study is useful in highlighting the rising opioid epidemic in young mothers, its associated mortality during delivery, as well as the significant adverse obstetrical outcomes.
Kathryn Tompkins, MD
Maeda A, Bateman BT, Clancy CR, Creanga AA, Leffert LR. Opioid abuse and dependence during pregnancy: temporal trends and obstetrical outcomes. Anesthesiology. 2014 Dec; 121(6):1158-65.