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Table 1 Characteristics of pregnancies resulting in a live or still birth, by exposure to oseltamivir

From: Oseltamivir in pregnancy and birth outcomes

Characteristic Before propensity score matching After propensity score matching
Unexposed to oseltamivir during pregnancy Exposed during first trimester Exposed during second or third trimester Unexposed to oseltamivir during pregnancy Exposed during first trimester Unexposed to oseltamivir during pregnancy Exposed during second or third trimester
Number 670,602 406 1449 397 397 1420 1420
Age at conception (years)
  < 20 14,636 (2.2) 11 (2.7) 32 (2.2) 6 (1.5) 11 (2.8) 23 (1.6) 31 (2.2)
 20-35 549,563 (82.0) 310 (76.4) 1114 (76.9) 301 (75.8) 303 (76.3) 1109 (78.1) 1088 (76.6)
  ≥ 35 106,403 (15.9) 85 (20.9) 303 (20.9) 90 (22.7) 83 (20.9) 288 (20.3) 301 (21.2)
Age at conception (years)
 Median (IQR) 30 (26–33) 30 (27–34) 30 (27–34) 31 (27–34) 30 (27–34) 31 (27–34) 30 (27–34)
 Mean (SD) 30.0 (4.9) 30.7 (5.0) 30.8 (4.9) 31.1 (4.9) 30.8 (5.0) 31.0 (4.8) 30.8 (4.9)
Calendar year of conception
 2002-2008 426,697 (63.6) 18 (4.4) 60 (4.1) 241 (60.7) 18 (4.5) 845 (59.5) 60 (4.2)
 2009-2010 118,496 (17.7) 376 (92.6) 1335 (92.1) 78 (19.6) 367 (92.4) 265 (18.7) 1310 (92.3)
 2011-2013 125,409 (18.7) 12 (3.0) 54 (3.7) 78 (19.6) 12 (3.0) 310 (21.8) 50 (3.5)
Unmarried 357,106 (53.3) 191 (47.0) 663 (45.8) 184 (46.3) 185 (46.6) 623 (43.9) 645 (45.4)
Pre-pregnancy body mass index (kg/m2)
  < 18.5 24,336 (3.6) 20 (4.9) 46 (3.2) 6 (1.5) 20 (5.0) 55 (3.9) 46 (3.2)
 18.5- < 25.0 355,498 (53.0) 238 (58.6) 835 (57.6) 204 (51.4) 233 (58.7) 766 (53.9) 822 (57.9)
 25.0- < 30.0 118,521 (17.7) 84 (20.7) 305 (21.0) 75 (18.9) 83 (20.9) 269 (18.9) 300 (21.1)
  ≥ 30 70,259 (10.5) 54 (13.3) 212 (14.6) 48 (12.1) 52 (13.1) 166 (11.7) 206 (14.5)
 Missing 101,988 (15.2) 10 (2.5) 51 (3.5) 64 (16.1) 9 (2.3) 164 (11.5) 46 (3.2)
Smoking
 No 561,830 (83.8) 351 (86.5) 1258 (86.8) 358 (90.2) 351 (88.4) 1275 (89.8) 1258 (88.6)
 Yes 95,528 (14.2) 46 (11.3) 162 (11.2) 39 (9.8) 46 (11.6) 145 (10.2) 162 (11.4)
 Missinga 13,244 (2.0) 9 (2.2) 29 (2.0)
Parity
 0 314,229 (46.9) 136 (33.5) 441 (30.4) 122 (30.7) 132 (33.2) 415 (29.2) 427 (30.1)
 1 242,531 (36.2) 183 (45.1) 637 (44.0) 187 (47.1) 179 (45.1) 654 (46.1) 627 (44.2)
 2 86,863 (13.0) 64 (15.8) 296 (20.4) 67 (16.9) 63 (15.9) 270 (19.0) 292 (20.6)
  > 2 26,979 (4.0) 23 (5.7) 75 (5.2) 21 (5.3) 23 (5.8) 81 (5.7) 74 (5.2)
Prior delivery of a child with a malformation (since 1994) 20,171 (3.0) 16 (3.9) 67 (4.6) 19 (4.8) 16 (4.0) 72 (5.1) 64 (4.5)
Hospital history during 12 months before conceptionb
 At least one inpatient hospitalization 124,627 (18.6) 83 (20.4) 334 (23.1) 75 (18.9) 79 (19.9) 270 (19.0) 327 (23.0)
 At least one visit to outpatient specialist clinic 232,129 (34.6) 169 (41.6) 609 (42.0) 155 (39.0) 165 (41.6) 570 (40.1) 597 (42.0)
 At least one emergency room visit 85,760 (12.8) 80 (19.7) 215 (14.8) 69 (17.4) 77 (19.4) 180 (12.7) 211 (14.9)
 Respiratory diseases 33,405 (5.0) 39 (9.6) 90 (6.2) 38 (9.6) 39 (9.8) 89 (6.3) 89 (6.3)
 Cardiovascular disease 7760 (1.2) 7 (1.7) 30 (2.1) 5 (1.3) 6 (1.5) 15 (1.1) 29 (2.0)
 Haematological disease 2364 (0.4) 5 (1.2) 15 (1.0) 0 (0.0) 5 (1.3) 8 (0.6) 15 (1.1)
 Diabetes 10,590 (1.6) 5 (1.2) 38 (2.6) 7 (1.8) 5 (1.3) 29 (2.0) 37 (2.6)
 Neurological diseaseb 5654 (0.8) 5 (1.2) 20 (1.4)
 Obesityc 73,216 (10.9) 56 (13.8) 222 (15.3) 49 (12.3) 54 (13.6) 174 (12.3) 216 (15.2)
 Disorders of female pelvic organs/genital tract 44,730 (6.7) 32 (7.9) 86 (5.9) 25 (6.3) 32 (8.1) 70 (4.9) 84 (5.9)
 Hospital contact for injury or poisoning 60,037 (9.0) 51 (12.6) 148 (10.2) 51 (12.8) 50 (12.6) 130 (9.2) 144 (10.1)
Use of prescription medication in the 12 months before conception
 Antidepressants 34,293 (5.1) 30 (7.4) 115 (7.9) 29 (7.3) 29 (7.3) 105 (7.4) 109 (7.7)
 Drugs for ulcer/gastroesophageal reflux 26,456 (3.9) 27 (6.7) 84 (5.8) 18 (4.5) 26 (6.5) 80 (5.6) 83 (5.8)
 Oral contraceptives 243,936 (36.4) 156 (38.4) 534 (36.9) 173 (43.6) 153 (38.5) 517 (36.4) 523 (36.8)
 Drugs for in-vitro fertilization 54,563 (8.1) 43 (10.6) 116 (8.0) 35 (8.8) 43 (10.8) 103 (7.3) 114 (8.0)
 Thyroid hormones 7284 (1.1) 8 (2.0) 25 (1.7) 8 (2.0) 8 (2.0) 31 (2.2) 24 (1.7)
 Systemic corticosteroids 13,005 (1.9) 17 (4.2) 49 (3.4) 17 (4.3) 16 (4.0) 41 (2.9) 49 (3.5)
 Non-steroidal anti-inflammatory drugs 98,907 (14.7) 78 (19.2) 268 (18.5) 66 (16.6) 77 (19.4) 252 (17.7) 261 (18.4)
 Opiates 21,777 (3.2) 18 (4.4) 58 (4.0) 17 (4.3) 17 (4.3) 76 (5.4) 57 (4.0)
 Systemic anti-infective agents other than oseltamivir 278,680 (41.6) 195 (48.0) 734 (50.7) 189 (47.6) 190 (47.9) 740 (52.1) 719 (50.6)
Number of different drugs classes dispensed, median (IQR) 1 (1–2) 2 (1–3) 2 (1-3) 2 (1–3) 2 (1–3) 2 (1–3) 2 (1–3)
  1. IQR interquartile range, SD standard deviation
  2. aMatching of the unexposed pregnancies was done separately for those exposed in the first trimester and those exposed in the second or third trimester. No matching of pregnancies with missing data on smoking
  3. bNot reported for the following protocol-specified characteristics because of low (< 5) group counts: liver and kidney disease; rheumatic disease; inflammatory bowel disease; immunodeficiency, and use of antiepileptics. In the propensity-score matched dataset neurologic diseases also not reported. cDefined by pre-pregnancy body mass index or a hospital diagnosis of obesity. Data are n (%) unless otherwise specified