Table 1.
Characteristics of moms and infants in pregnancies exposed and unexposed to biologics
| Maternal characteristics | Biologic exposed | Biologic unexposed | P value¶ |
| Current pregnancy | |||
| Maternal age at delivery (mean (SD)) | 31.0 (4.7) | 31.2 (5.2) | 0.657 |
| Multiparous | 44 (44%) | 4998 (59%) | 0.003 |
| Antenatal visits (mean (SD)) | 8.9 (3.6) | 9.0 (3.9) | 0.749 |
| Gestational hypertension | 5 (5%) | 647 (8%) | 0.328 |
| Gestational diabetes | 12 (12%) | 669 (8%) | 0.128 |
| Delivery via caesarean section | 40 (40%) | 2849 (33%) | 0.171 |
| Neighbourhood income quintiles | |||
| 5th percentile | 21 (21%) | 1763 (21%) | 0.836 |
| 25th percentile | 24 (24%) | 1699 (20%) | |
| Median (50th percentile) | 17 (17%) | 1845 (22%) | |
| 75th percentile | 22 (22%) | 1803 (21%) | |
| 95th percentile | 16 (16%) | 1397 (16%) | |
| Hospitalisation at baseline | 99 (99%) | 8412 (99%) | 0.912 |
| BMI at baseline (mean (SD)) | 24.7 (4.6) | 24.6 (4.5) | 0.867 |
| BMI categories | |||
| Obese | 9 (9%) | 851 (10%) | 0.979 |
| Overweight | 15 (15%) | 1342 (16%) | |
| Prior obstetrical history | |||
| Premature delivery | 5 (5%) | 500 (6%) | 0.711 |
| Spontaneous abortion | 28 (28%) | 2230 (26%) | 0.686 |
| Delivery with neonatal death | <5* | 52 (0.6%) | 0.621 |
| Stillbirth | <5* | 103 (1%) | 0.107 |
| Low birthweight infant | 5 (5%) | 243 (3%) | 0.203 |
| Infant with anomalies | 0 (0%) | 74 (1%) | 0.349 |
| Autoimmune disease type† | |||
| Inflammatory bowel disease | 50 (50%) | 2471 (29%) | <0.001 |
| Rheumatoid arthritis | 44 (44%) | 1756 (21%) | <0.001 |
| Psoriasis/psoriatic arthritis | 16 (16%) | 3441 (40%) | <0.001 |
| Juvenile idiopathic arthritis | 8 (8%) | 93 (1%) | <0.001 |
| Systemic autoimmune rheumatic diseases | 5 (5%) | 1063 (12%) | 0.024 |
| Ankylosing spondylitis | 5 (5%) | 417 (5%) | 0.964 |
| Biologics‡ | |||
| Infliximab | 54 (54%) | ||
| Etanercept | 41 (41%) | ||
| Adalimumab | 39 (39%) | ||
| Other biologic§ | 18 (18%) | ||
| Concomitant medications | |||
| DMARDs | 53 (53%) | 1843 (22%) | <0.001 |
| Glucocorticoids | 54 (54%) | 1065 (13%) | <0.001 |
| Traditional NSAIDs | 16 (16%) | 941 (11%) | 0.118 |
| Antidepressants | 16 (16%) | 783 (9%) | 0.020 |
| Anxiolytics | <5* | 394 (5%) | 0.765 |
| COX2 NSAIDs | <5* | 56 (0.7%) | <0.001 |
| Comorbidities | |||
| Anxiety | 19 (19%) | 1368 (16%) | 0.430 |
| Mood disorders | 10 (10%) | 432 (5%) | 0.027 |
| Asthma | <5* | 154 (2%) | 0.888 |
| Diabetes | <5* | 563 (6.6%) | 0.294 |
| Hypertension | 6 (6%) | 975 (11.5%) | 0.088 |
| Infant characteristics | Biologic exposed | Biologic unexposed | |
| Female sex | 55 (55%) | 4159 (49%) | 0.224 |
| Gestational age (mean (SD)) | 37.8 weeks (2.4) | 38.4 weeks (2.2) | 0.004 |
| Birth weight (mean (SD)) | 3158 g (634) | 3385 g (204) | <0.001 |
| Apgar score at 1 min (mean (SD)) | 8.1 (1.6) | 8.0 (1.7) | 0.730 |
| Apgar score at 5 min (mean (SD)) | 8.9 (1.1) | 9.0 (1.0) | 0.595 |
*All cell sizes <5 are suppressed due to privacy restrictions of data sharing agreements.
†Sum of percentages exceed 100% due to some individuals having more than one diagnosis.
‡Sum of percentages exceed 100% due to some pregnancies being exposed to more than one drug.
§Other biologics include: abatacept, alefacept, certolizumab pegol, golimumab, rituximab, tocilizumab and ustekinumab.
¶P values based on t-tests or χ2 tests.
BMI, body mass index; COX, cyclooxygenase; DMARDs, disease-modifying antirheumatic drugs; NSAIDs, non-steroidal anti-inflammatory drugs.