Table 3. Unadjusted, Confounder-Adjusted, Confounder/Mediator-Adjusted, and Propensity-Matched Relative Risks (RRs) and 95% CIs for All Outcomes Referent to Receiving No Epidural (RR = 1)a.
| Outcome | Unadjusted | Confounder adjusted (Cadj) | Confounder and mediator (mode of delivery) adjusted (CMadj) | Propensity matching (Cadj) | ||||
|---|---|---|---|---|---|---|---|---|
| RR (95% CI) | P value | RR (95% CI) | P value | RR (95% CI) | P value | RR (95% CI) | P value | |
| Mode of delivery | ||||||||
| SVD | 0.46 (0.46-0.47) | <.001 | 0.46 (0.42-0.50) | <.001 | NA | NA | NA | NA |
| Breech | 0.26 (0.06-1.09) | .06 | 0.61 (0.09-4.01) | .70 | NA | NA | NA | NA |
| Emergency cesarean delivery | 2.55 (2.50-2.60) | <.001 | 1.62 (1.46-1.81) | <.001 | NA | NA | NA | NA |
| Instrumental | 3.54 (3.48-3.60) | <.001 | 2.50 (2.29-2.73) | <.001 | NA | NA | NA | NA |
| Rotational | 4.09 (3.92-4.27) | <.001 | 2.86 (2.15-3.81) | <.001 | NA | NA | NA | NA |
| Neonatal resuscitation | 1.15 (1.11-1.19) | <.001 | 1.07 (1.03-1.11) | .003 | 0.83 (0.79-0.86) | <.001 | 0.99 (0.95-1.04) | .76 |
| Apgar score, points | ||||||||
| <7 at 5 min | 0.91 (0.85-0.97) | .003 | 0.92 (0.86-0.99) | .02 | 0.74 (0.69-0.79) | <.001 | 0.84 (0.78-0.91) | <.001 |
| <4 at 5 min | 0.97 (0.85-1.10) | .60 | 1.04 (0.91-1.18) | .58 | 0.83 (0.72-0.95) | .008 | 1.01 (0.83-1.22) | .95 |
| Admitted to neonatal unit | 1.01 (0.98-1.03) | .70 | 1.14 (1.11-1.17) | <.001 | 0.94 (0.91-0.97) | <.001 | 1.10 (1.06-1.14) | <.001 |
| Offspring | ||||||||
| No. of unique conditions up to age 2 y | 1.03 (1.01-1.05) | <.001 | 1.06 (1.04-1.09) | <.001 | 1.06 (1.04-1.08) | <.001 | 1.07 (1.04-1.10) | <.001 |
| No. of days in hospital up to age 2 y | 0.92 (0.86-0.99) | .02 | 1.04 (0.98-1.11) | .19 | 1.03 (0.96-1.10) | .39 | 1.06 (0.97-1.15) | .20 |
| No. of operations up to age 2 y | 0.94 (0.90-0.98) | .006 | 1.01 (0.96-1.06) | .72 | 1.00 (0.95-1.05) | .86 | 1.01 (0.95-1.07) | .81 |
| Concern at age 2 y | ||||||||
| Gross motor | 0.85 (0.79-0.92) | <.001 | 0.95 (0.88-1.03) | .25 | 0.91 (0.83-0.99) | .03 | 0.95 (0.85-1.05) | .32 |
| Fine motor | 0.81 (0.75-0.87) | <.001 | 0.91 (0.84-0.98) | .01 | 0.89 (0.82-0.97) | .005 | 0.91 (0.82-1.00) | .06 |
| Communication | 0.91 (0.88-0.94) | <.001 | 0.96 (0.93-0.99) | .01 | 0.96 (0.93-0.99) | .02 | 0.97 (0.93-1.01) | .09 |
| Social | 0.93 (0.88-0.98) | .007 | 0.98 (0.93-1.04) | .52 | 0.95 (0.90-1.01) | .12 | 0.98 (0.91-1.05) | .51 |
| Any | 0.91 (0.89-0.94) | <.001 | 0.96 (0.93-0.98) | .001 | 0.96 (0.93-0.98) | <.001 | 0.96 (0.92-0.99) | .03 |
Abbreviations: Cadj, confounder adjusted; CMadj, confounder and mediator adjusted; NA, not applicable; RR, relative risk; SVD, spontaneous vaginal delivery.
a
Results are adjusted for maternal age, maternal weight, Scottish Index of Multiple Deprivation decile, race and ethnicity, smoking history, illicit drug use, induction of labor, parity, previous cesarean section, previous spontaneous or therapeutic abortion, preeclampsia, diabetes, gestational age, birthweight, year of birth, and sex of neonate.