Table 2.
Crude and adjusted (IP-weighted) odds ratios of adverse neonatal and pregnancy outcomes associated with prenatal exposure to buprenorphine or methadone both early and late in pregnancy compared with untreated pregnancies.
| Exposure to OATs in both early and late pregnancya,b | |||
|---|---|---|---|
| Neonatal outcomes | Cases, n (%) | Crude OR (95% CI) | Weighted OR (95% CI) |
| Preterm birth (<37 weeks) | |||
| Buprenorphine | <11 | 0.26 (0.07, 1.00) | 0.17 (0.04, 0.77) |
| Methadone | 31 (24.8) | 2.03 (1.08, 3.84) | 2.52 (1.07, 5.95) |
| Untreated | 22 (14.47) | Ref. | Ref. |
| Low birthweight (<2500 g) | |||
| Buprenorphine | <11 | 0.32 (0.11, 0.93) | 0.41 (0.12, 1.40) |
| Methadone | 35 (28) | 2.13 (1.18, 3.82) | 2.99 (1.34, 6.66) |
| Untreated | 23 (15.13) | Ref. | Ref. |
| Neonatal Intensive Care Unit Admission (NICUa) | |||
| Buprenorphine | 18 (27.69) | 1.83 (0.92, 3.65) | 1.78 (0.77, 4.14) |
| Methadone | 69 (55.2) | 5.90 (3.40, 10.23) | 5.04 (2.49, 10.21) |
| Untreated | 27 (17.76) | Ref. | Ref. |
| Neonatal abstinence syndrome (NAS) | |||
| Buprenorphine | 37 (56.92) | 8.28 (4.23, 16.19) | 10.27 (4.91, 21.47) |
| Methadone | 75 (60) | 10.50 (5.90, 18.68) | 11.36 (5.65, 22.82) |
| Untreated | 19 (12.5) | Ref. | Ref. |
| Respiratory symptoms | |||
| Buprenorphine | 11 (16.92) | 1.51 (0.67, 3.39) | 1.79 (0.67, 4.76) |
| Methadone | 29 (23.2) | 2.39 (1.28, 4.47) | 2.71 (1.17, 6.24) |
| Untreated | 17 (11.18) | Ref. | Ref. |
| Feeding difficulties | |||
| Buprenorphine | 18 (27.69) | 1.20 (0.63, 2.30) | 1.52 (0.65, 3.57) |
| Methadone | 16 (12.8) | 0.49 (0.26, 0.90) | 0.57 (0.27, 1.21) |
| Untreated | 36 (23.68) | Ref. | Ref. |
| Small for gestational age | |||
| Buprenorphine | <11 | 2.46 (0.90, 6.77) | 3.15 (1.00, 9.94) |
| Methadone | 19 (15.2) | 2.65 (1.14, 6.21) | 3.54 (1.23, 10.22) |
| Untreated | 11 (7.24) | Ref. | Ref. |
| Maternal and obstetrical complications | |||
| Length of maternal hospital stay (>7 days)c | |||
| Buprenorphine | 28 (43.08) | 3.35 (1.79, 6.28) | 3.84 (1.83, 8.07) |
| Methadone | 91 (72.8) | 11.60 (6.62, 20.31) | 14.51 (7.23, 29.12) |
| Untreated | 29 (19.08) | Ref. | Ref. |
| Caesarean delivery | |||
| Buprenorphine | 23 (35.38) | 1.07 (0.60, 1.93) | 1.08 (0.54, 2.14) |
| Methadone | 34 (27.2) | 0.62 (0.37, 1.04) | 0.79 (0.41, 1.52) |
| Untreated | 55 (36.18) | Ref. | Ref. |
| Preeclampsia | |||
| Buprenorphine | <11 | 0.86 (0.13, 5.60) | 0.66 (0.08, 5.34) |
| Methadone | <11 | 1.60 (0.45, 5.67) | 1.69 (0.43, 6.68) |
| Untreated | <11 | Ref. | 0.66 (0.08, 5.34) |
| Postpartum hemorrhage | |||
| Buprenorphine | <11 | 2.14 (0.54, 8.49) | 1.51 (0.33, 6.89) |
| Methadone | <11 | 0.62 (0.13, 3.04) | 0.65 (0.13, 3.14) |
| Untreated | <11 | Ref. | Ref. |
Abbreviations: IP = inverse probability; OR = odds ratios; CI = confidence intervals.
Small cell count <11 was suppressed.
Stabilized inverse-probability treatment weights (IPTWs) of early and late exposure were computed with the numerator model adjusting for baseline covariates (i.e., maternal age, race, year of birth, multiple gestation, pre-existing comorbid conditions, and healthcare resource utilization at baseline), and the denominator model adjusting for additional time-varying comedication use, substances use, and markers of OUD severity. Previous exposure history was included in the models for late exposure. Infant sex was included for adverse neonatal outcomes. A product of stabilized IPTWs for early and late exposure was used in outcome models.
Missing values were ≤0.5% and only complete cases were analyzed.