Table 1.
Unadjusted and propensity score adjusted baseline characteristics of children whose mothers were prescribed macrolides or penicillins from four to 13 gestational weeks (first trimester). Values are numbers (percentages) unless indicated otherwise
| Characteristics | Unadjusted | Propensity score adjusted* | |||||
|---|---|---|---|---|---|---|---|
| Macrolides | Penicillins | St.diff | Macrolides | Penicillins | St.diff | ||
| No of children | 2170 | 22 544 | — | 2170 | 22 509.8 | — | |
| Maternal baseline characteristics | |||||||
| Age at delivery: | — | — | 0.108 | — | — | 0.008 | |
| 13-19 | 130 (6.0) | 986 (4.4) | — | 130 (6.0) | 1372.2 (6.1) | — | |
| 20-24 | 377 (17.4) | 3510 (15.6) | — | 377 (17.4) | 3881.9 (17.2) | — | |
| 25-29 | 524 (24.1) | 6223 (27.6) | — | 524 (24.1) | 5437.1 (24.2) | — | |
| 30-34 | 664 (30.6) | 6892 (30.6) | — | 664 (30.6) | 6941.3 (30.8) | — | |
| 35-50 | 475 (21.9) | 4933 (21.9) | — | 475 (21.9) | 4877.3 (21.7) | — | |
| Calendar year of delivery: | — | — | 0.115 | — | — | 0.016 | |
| 1990-94 | 170 (7.8) | 2225 (9.9) | — | 170 (7.8) | 1843.0 (8.2) | — | |
| 1995-99 | 318 (14.7) | 3746 (16.6) | — | 318 (14.7) | 3323.8 (14.8) | — | |
| 2000-04 | 496 (22.9) | 4404 (19.5) | — | 496 (22.9) | 5175.9 (23.0) | — | |
| 2005-09 | 568 (26.2) | 5594 (24.8) | — | 568 (26.2) | 5781.4 (25.7) | — | |
| 2010-16 | 618 (28.5) | 6575 (29.2) | — | 618 (28.5) | 6385.8 (28.4) | — | |
| Alcohol misuse | 129 (5.9) | 1047 (4.6) | 0.058 | 129 (5.9) | 1353.6 (6.0) | 0.003 | |
| Illicit drug use | 31 (1.4) | 243 (1.1) | 0.032 | 31 (1.4) | 323.6 (1.4) | 0.001 | |
| Tobacco use | 790 (36.4) | 7412 (32.9) | 0.074 | 790 (36.4) | 8168.1 (36.3) | 0.002 | |
| Obesity | 262 (12.1) | 2578 (11.4) | 0.020 | 262 (12.1) | 2742.7 (12.2) | 0.003 | |
| Hypertension | 161 (7.4) | 1623 (7.2) | 0.008 | 161 (7.4) | 1655.9 (7.4) | 0.002 | |
| Diabetes | 68 (3.1) | 782 (3.5) | 0.019 | 68 (3.1) | 710.3 (3.2) | 0.001 | |
| Anxiety | 74 (3.4) | 556 (2.5) | 0.056 | 74 (3.4) | 763.1 (3.4) | 0.001 | |
| Depression | 227 (10.5) | 2288 (10.1) | 0.01 | 227 (10.5) | 2381.0 (10.6) | 0.004 | |
| Epilepsy | 25 (1.2) | 155 (0.7) | 0.049 | 25 (1.2) | 238.4 (1.1) | 0.009 | |
| Pregnancy related characteristics | |||||||
| Parity ≥1 | 782 (36.0) | 8080 (35.8) | 0.004 | 782 (36.0) | 8070.8 (35.9) | 0.004 | |
| Multiple births | 52 (2.4) | 535 (2.4) | 0.002 | 52 (2.4) | 564.5 (2.5) | 0.007 | |
| Genitourinary tract infection | 90 (4.1) | 2796 (12.4) | 0.303 | 90 (4.1) | 889.2 (4.0) | 0.010 | |
| Sexually transmitted infection | 102 (4.7) | 301 (1.3) | 0.198 | 102 (4.7) | 978.2 (4.3) | 0.017 | |
| Treatment of chronic medical conditions | 422 (19.4) | 4066 (18.0) | 0.036 | 422 (19.4) | 4388.4 (19.5) | 0.001 | |
Exposure propensity scores were measured as predicted probability of receiving macrolides versus penicillins, conditional on maternal and pregnancy related characteristics included in this table. Fifty strata were created based on distribution of propensity score of macrolides group. Weights for penicillin group were calculated according to distribution of macrolide group among strata and were used to estimate adjusted baseline characteristics. A meaningful between group imbalance was assessed by absolute standardised difference (St.diff=difference in means in units of standard deviation) of more than 0.1. Numbers in adjusted penicillin group were non-integer because they were weighted based on distribution of propensity score of macrolide group.