Table 4. Frequency and Adjusted Risk Ratios (aRRs) of Maternal Outcomes by Prenatal Cannabis Use Defined Only by Self-Report or Defined Only by Toxicology Testing.
| Outcome | Overall (N = 316 722 [100%]) | Prenatal cannabis use defined only by self-report | Prenatal cannabis use defined only by toxicology testing | ||||
|---|---|---|---|---|---|---|---|
| Any prenatal cannabis use, No. (%) | aRR (95% CI)a | Any prenatal cannabis use, No. (%) | aRR (95% CI)a | ||||
| Yes (n = 9167 [2.9%]) | No (n = 307 555 [97.1%]) | Yes (n = 16 638 [5.3%]) | No (n = 300 084 [94.7%]) | ||||
| Metabolic outcomes | |||||||
| Hypertensive disordersb | |||||||
| Gestational hypertension | 44 363 (14.7) | 1715 (19.8) | 42 648 (14.5) | 1.10 (1.05-1.15) | 3511 (22.5) | 41 614 (14.5) | 1.19 (1.15-1.23) |
| Preeclampsia | 14 378 (4.8) | 529 (6.1) | 13 849 (4.7) | 0.99 (0.90-1.08) | 1016 (6.5) | 13 362 (4.7) | 1.11 (1.04-1.19) |
| Eclampsia | 384 (0.1) | 16 (0.2) | 368 (0.1) | 1.21 (0.70-2.09) | 27 (0.2) | 357 (0.1) | 1.09 (0.72-1.65) |
| Gestational diabetesc | 36 374 (11.7) | 650 (7.2) | 35 724 (11.8) | 0.91 (0.84-0.98) | 1279 (7.8) | 35 095 (11.9) | 0.89 (0.84-0.94) |
| Gestational weight gaind | |||||||
| Within guidelines | 75 844 (25.2) | 1603 (18.5) | 74 241 (25.4) | NA | 2636 (16.5) | 73 208 (25.7) | NA |
| Less than guidelines | 48 117 (16.0) | 1279 (14.8) | 46 838 (16.0) | 1.05 (1.00-1.09) | 2296 (14.4) | 45 821 (16.1) | 1.05 (1.01-1.08) |
| Greater than guidelines | 176 898 (58.8) | 5781 (66.7) | 171 117 (58.6) | 1.05 (1.04-1.06) | 11 021 (69.1) | 165 877 (58.2) | 1.10 (1.09-1.11) |
| Placental outcomes | |||||||
| Placenta previa | 3499 (1.1) | 86 (0.9) | 3413 (1.1) | 1.15 (0.92-1.44) | 136 (0.8) | 3363 (1.1) | 1.01 (0.84-1.20) |
| Placental abruption | 4002 (1.3) | 132 (1.4) | 3870 (1.3) | 1.22 (1.01-1.47) | 236 (1.4) | 3766 (1.3) | 1.19 (1.03-1.37) |
| Placenta accretae | 499 (0.2) | 16 (0.2) | 483 (0.2) | 1.28 (0.74-2.20) | 34 (0.2) | 465 (0.2) | 1.44 (0.98-2.13) |
| Severe maternal morbidity | 10 338 (3.3) | 333 (3.6) | 10 005 (3.3) | 0.97 (0.87-1.09) | 593 (3.6) | 9745 (3.2) | 0.96 (0.88-1.05) |
Abbreviation: NA, not applicable.
Reference is no prenatal cannabis use. Modified Poisson models with robust standard errors were adjusted for maternal sociodemographic characteristics (age category, race and ethnicity, neighborhood deprivation index), parity, birth year, prenatal care initiation, prepregnancy body mass index category, other noncannabis prenatal substance use (alcohol, nicotine, opioids, stimulants, and anxiety/sleep medications), and maternal medical and mental health comorbidities (pregestational diabetes, nausea/vomiting during pregnancy, mood/anxiety disorders, other psychiatric disorders, substance use disorders [other than cannabis], and antidepressant use).
Pregnancies of individuals with chronic hypertension were excluded (n = 14 187).
Pregnancies of individuals with pregestational diabetes were excluded. In addition, gestational diabetes could not be ascertained for pregnancies ending in therapeutic abortion. A total of 4737 pregnancies were excluded. Pregestational diabetes was not included as a covariate.
Categories determined by the 2009 Institute of Medicine guidelines. Pregnancies with missing weight values were excluded (n = 15 863).
Placenta accreta could only be ascertained for pregnancies that were delivered in a Kaiser Permanente Northern California facility and ended in live birth or stillbirth (alive at admission); 10 979 were excluded.