Table 3. Age Group–by-Time and Parity-by-Time Interaction Models: Multivariable Random Slope Mixed-Effects Models of Changes in Desire to Avoid Pregnancy Score, March 16, 2019, to March 15, 2021.
| Interaction model | Coefficient (95% CI)a,b | P value for interaction | Joint P value for interactions |
|---|---|---|---|
| Age group (reference, 25-34 y) | |||
| Age 15-24 y | 0.26 (0.07 to 0.44) | NA | NA |
| Time before summer 2020 surgec | −0.04 (−0.06 to −0.02) | NA | NA |
| Time after summer 2020 surgec | 0.04 (−0.08 to 0.15) | NA | NA |
| Time after fall 2020 surgec | −0.05 (−0.31 to 0.21) | NA | NA |
| Age 15-24 y by time interaction before summer 2020 surgec | −0.03 (−0.07 to −0.002) | .04 | .05 |
| Age 15-24 y by time interaction after summer 2020 surgec | 0.21 (0.04 to 0.38) | .02 | |
| Age 15-24 y by time interaction after fall 2020 surgec | −0.29 (−0.67 to 0.09) | .13 | |
| Parity (reference, multiparous) | |||
| Nulliparous-primiparous | −0.11 (−0.31 to 0.08) | NA | NA |
| Time before summer 2020 surgec | −0.03 (−0.06 to −0.004) | NA | NA |
| Time after summer 2020 surgec | 0.04 (−0.10 to 0.19) | NA | NA |
| Time after fall 2020 surgec | 0.08 (−0.25 to 0.41) | NA | NA |
| Nulliparous-primiparous by time interaction before summer 2020 surgec | −0.04 (−0.07 to −0.001) | .04 | .06 |
| Nulliparous-primiparous by time interaction after summer 2020 surgec | 0.14 (−0.04 to 0.31) | .14 | |
| Nulliparous-primiparous by time interaction after fall 2020 surgec | −0.41 (−0.81 to −0.001) | .05 |
Abbreviation: NA, not applicable.
a
Models include participant age, race and ethnicity, parity, partnership and cohabitation, food insecurity, and recruitment site. The Desire to Avoid Pregnancy score is on a range of 0 to 4 points, with 4 indicating greater desire to avoid pregnancy.
b
Slope between change points can be derived by summing coefficients.
c
Time is treated continuously; coefficients and slopes are reported in quarters (eg, per 3 months).