Table 1

Characteristics of moms and infants in pregnancies exposed and unexposed to biologics

Maternal characteristicsBiologic exposedBiologic unexposedP value¶
Current pregnancy
Maternal age at delivery (mean (SD))31.0 (4.7)31.2 (5.2)0.657
Multiparous44 (44%)4998 (59%)0.003
Antenatal visits (mean (SD))8.9 (3.6)9.0 (3.9)0.749
Gestational hypertension5 (5%)647 (8%)0.328
Gestational diabetes12 (12%)669 (8%)0.128
Delivery via caesarean section40 (40%)2849 (33%)0.171
Neighbourhood income quintiles
 5th percentile21 (21%)1763 (21%)0.836
 25th percentile24 (24%)1699 (20%)
 Median (50th percentile)17 (17%)1845 (22%)
 75th percentile22 (22%)1803 (21%)
 95th percentile16 (16%)1397 (16%)
Hospitalisation at baseline99 (99%)8412 (99%)0.912
BMI at baseline (mean (SD))24.7 (4.6)24.6 (4.5)0.867
BMI categories
 Obese9 (9%)851 (10%)0.979
 Overweight15 (15%)1342 (16%)
Prior obstetrical history
Premature delivery5 (5%)500 (6%)0.711
Spontaneous abortion28 (28%)2230 (26%)0.686
Delivery with neonatal death<5*52 (0.6%)0.621
Stillbirth<5*103 (1%)0.107
Low birthweight infant5 (5%)243 (3%)0.203
Infant with anomalies0 (0%)74 (1%)0.349
Autoimmune disease type†
Inflammatory bowel disease50 (50%)2471 (29%)<0.001
Rheumatoid arthritis44 (44%)1756 (21%)<0.001
Psoriasis/psoriatic arthritis16 (16%)3441 (40%)<0.001
Juvenile idiopathic arthritis8 (8%)93 (1%)<0.001
Systemic autoimmune rheumatic diseases5 (5%)1063 (12%)0.024
Ankylosing spondylitis5 (5%)417 (5%)0.964
Biologics‡
Infliximab54 (54%)
Etanercept41 (41%)
Adalimumab39 (39%)
Other biologic§18 (18%)
Concomitant medications
DMARDs53 (53%)1843 (22%)<0.001
Glucocorticoids54 (54%)1065 (13%)<0.001
Traditional NSAIDs16 (16%)941 (11%)0.118
Antidepressants16 (16%)783 (9%)0.020
Anxiolytics<5*394 (5%)0.765
COX2 NSAIDs<5*56 (0.7%)<0.001
Comorbidities
Anxiety19 (19%)1368 (16%)0.430
Mood disorders10 (10%)432 (5%)0.027
Asthma<5*154 (2%)0.888
Diabetes<5*563 (6.6%)0.294
Hypertension6 (6%)975 (11.5%)0.088
Infant characteristicsBiologic exposedBiologic unexposed
Female sex55 (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.