Table 1.
Characteristics of 41 523 women who were categorised by whether they were prescribed an antipsychotic drug during pregnancy. Of these, 1021 antipsychotic drug users were matched 1:1 with 1021 non-users by means of a high dimensional propensity score (HDPS) algorithm. Values are numbers (percentages) unless stated otherwise
| Measure | Unmatched cohort | Matched cohort | |||||
|---|---|---|---|---|---|---|---|
| Antipsychotic users (n=1209) | Non-users (n=40 314) | Standardised difference | Antipsychotic users (n=1021) | Non-users (n=1021) | Standardised difference | ||
| Demographic characteristics | |||||||
| Mean (SD) age (years) | 28.8 (6.1) | 26.7 (6.3) | 0.35 | 28.8 (6.2) | 28.8 (6.2) | <0.01 | |
| Median (interquartile range) parity | 1 (0–2) | 1 (0–2) | 0.14 | 1 (0–2) | 1 (0–2) | 0.07 | |
| Lowest neighbourhood income quintile | 613 (50.7) | 20 722 (51.4) | 0.01 | 501 (49.1) | 458 (45.0) | 0.08 | |
| Urban residence | 1106 (91.5) | 36452 (90.4) | 0.04 | 930 (91.1) | 909 (89.2) | 0.06 | |
| Medical morbidity | |||||||
| Pre-pregnancy diabetes | 52 (4.3) | 1303 (3.2) | 0.06 | 39 (3.8) | 42 (4.1) | 0.02 | |
| Pre-pregnancy chronic hypertension | 44 (3.6) | 1276 (3.2) | 0.03 | 39 (3.8) | 49 (4.8) | 0.05 | |
| Venous thromboembolism <1 year before index pregnancy | 28 (2.3) | 672 (1.7) | 0.05 | 25 (2.5) | 23 (2.3) | 0.01 | |
| High resource utilisation band of 4 or 5 | 927 (76.7) | 29 050 (72.1) | 0.42 | 767 (73.1) | 799 (78.3) | 0.11 | |
| Prenatal care | |||||||
| Prenatal ultrasound before 20 weeks gestation | 1049 (86.8) | 35 372 (87.8) | 0.03 | 885 (86.7) | 884 (86.6) | <0.01 | |
| Mean (SD) No of prenatal visits | 18.3 (10.3) | 15.3 (7.2) | 0.33 | 18.1 (10.2) | 18.5 (11.0) | 0.03 | |
| Prenatal care provider: | 0.15 | 0.06 | |||||
| Primary care | 288 (23.8) | 8002 (19.9) | 244 (23.9) | 230 (22.5) | |||
| Obstetrician | 276 (22.8) | 11 362 (28.2) | 234 (22.9) | 237 (23.2) | |||
| Primary care and obstetrician | 614 (50.8) | 19 556 (48.5) | 514 (50.3) | 516 (50.5) | |||
| Other (such as midwife) | 31 (2.6) | 1394 (3.5) | 29 (2.8) | 38 (3.7) | |||
| Mental health measures | |||||||
| Mean (SD) No of outpatient visits <1 year before index pregnancy | 8.46 (11.1) | 1.48 (5.3) | 0.80 | 7.83 (10.8) | 9.15 (15.0) | 0.10 | |
| Emergency department visit <1 year before index pregnancy | 326 (27.0) | 2211 (5.5) | 0.61 | 242 (23.7) | 228 (22.3) | 0.03 | |
| Admission <1 year before index pregnancy | 249 (20.6) | 552 (1.4) | 0.65 | 158 (15.5) | 133 (13.0) | 0.07 | |
| Prescribed antipsychotic drug <1 year before index pregnancy* | 1075 (88.9) | 1334 (3.3) | 3.35 | 895 (87.7) | 274 (26.8) | 1.56 | |
| Psychiatric diagnoses before index pregnancy: | |||||||
| Psychotic disorder | 429 (35.5) | 675 (1.69) | 0.97 | 319 (31.2) | 160 (15.7) | 0.37 | |
| Bipolar disorder or major depression | 937 (77.5) | 8708 (21.6) | 1.35 | 758 (74.2) | 673 (65.9) | 0.18 | |
| Alcohol or substance disorder (including smoking) | 569 (47.1) | 5523 (13.7) | 0.78 | 458 (44.9) | 415 (40.7) | 0.08 | |
| Personality disorder | 393 (32.5) | 1816 (4.5) | 0.77 | 295 (28.9) | 231 (22.6) | 0.14 | |
| Non-antipsychotic drug prescribed in the pregnancy: | |||||||
| SSRI | 364 (30.1) | 1981 (4.9) | 0.70 | 303 (29.7) | 204 (20.0) | 0.23 | |
| Non-SSRI | 322 (26.6) | 989 (2.5) | 0.73 | 264 (25.9) | 149 (14.6) | 0.28 | |
| Mood stabiliser | 167 (13.8) | 331 (0.8) | 0.52 | 105 (10.3) | 62 (6.1) | 0.15 | |
| Benzodiazepine | 306 (25.3) | 630 (1.6) | 0.74 | 222 (21.7) | 135 (13.2) | 0.23 | |
SSRI=selective serotonin reuptake inhibitor (fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram). Non-SSRI=serotonin-norepinephrine reuptake inhibitors (mirtazapine, buproprion, tricyclic antidepressants, monoamine oxidase inhibitors). Mood stabiliser (lithium, valproate, carbamazepine, lamotrigine, oxcarbazepine).
*Prescription of an antipsychotic drug in the year before the estimated date of conception was not included in the derivation of the high dimensional propensity score.