Table 4.
Crude and adjusted (IP-weighted) odds ratios of adverse neonatal and pregnancy outcomes associated with prenatal exposure to methadone both early and late in pregnancy compared with buprenorphine both early and late in pregnancy.
| 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 | Ref. | Ref. |
| Methadone | 31 (24.8) | 7.77 (2.14, 28.18) | 14.49 (3.20, 65.57) |
| Low birthweight (<2500 g) | |||
| Buprenorphine | <11 | Ref. | Ref. |
| Methadone | 35 (28) | 6.75 (2.32, 19.66) | 7.36 (2.18, 24.87) |
| Neonatal Intensive Care Unit Admission (NICUa) | |||
| Buprenorphine | 18 (27.69) | Ref. | Ref. |
| Methadone | 69 (55.2) | 3.23 (1.71, 6.06) | 2.83 (1.23, 6.48) |
| Neonatal abstinence syndrome (NAS) | |||
| Buprenorphine | 37 (56.92) | Ref. | Ref. |
| Methadone | 75 (60) | 1.27 (0.70, 2.30) | 1.11 (0.54, 2.28) |
| Respiratory symptoms | |||
| Buprenorphine | 11 (16.92) | Ref. | Ref. |
| Methadone | 29 (23.2) | 1.58 (0.75, 3.34) | 1.51 (0.55, 4.12) |
| Feeding difficulties | |||
| Buprenorphine | 18 (27.69) | Ref. | Ref. |
| Methadone | 16 (12.8) | 0.40 (0.20, 0.83) | 0.37 (0.15, 0.92) |
| Small for gestational age | |||
| Buprenorphine | <11 | Ref. | Ref. |
| Methadone | 19 (15.2) | 1.08 (0.46, 2.53) | 1.12 (0.43, 2.96) |
| Maternal and obstetrical complications | |||
| Length of maternal hospital stay (>7 days)c | |||
| Buprenorphine | 28 (43.08) | Ref. | Ref. |
| Methadone | 91 (72.8) | 3.46 (1.86, 6.42) | 3.77 (1.80, 7.90) |
| Caesarean delivery | |||
| Buprenorphine | 23 (35.38) | Ref. | Ref. |
| Methadone | 34 (27.2) | 0.57 (0.31, 1.07) | 0.74 (0.35, 1.57) |
| Preeclampsia | |||
| Buprenorphine | <11 | Ref. | Ref. |
| Methadone | <11 | 1.86 (0.33, 10.60) | 2.56 (0.45, 14.43) |
| Postpartum hemorrhage | |||
| Buprenorphine | <11 | Ref. | Ref. |
| Methadone | <11 | 0.29 (0.06, 1.37) | 0.43 (0.07, 2.45) |
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.