Table 3: Stress and perception of child behaviour by levels of postpartum distress (PD)- Means, p values and effect sizes for means

Outcomes (low values are favourable) Means and percentages1 Unadjusted analyses: P values2 Adjusted P values3 Effect sizes for means4
Parenthood stress, means (1-5) Low PD Medium PD High PD Low-Medium PD DF=1 Medium-High PD DF=1 Low-High PD DF=1 All PD groups DF=2 Multiple logistic regressions Low-Medium PD Medium-High PD Low-High PD
SPSQ: total 2.37 2.7 2.85 <.0001 0.0477 <.0001 <.0001 <.0001 0.65 0.27 0.91
SPSQ: social isolation 1.99 2.29 2.43 <.0001 0.1689 <.0001 <.0001 <.0001 0.42 0.2 0.68
SPSQ: role restriction 3.36 3.66 3.82 <.0001 0.122 <.0001 <.0001 <.0001 0.4 0.22 0.63
SPSQ: incompetence 2.05 2.42 2.65 <.0001 0.042 <.0001 <.0001 <.0001 0.59 0.31 0.84
SPSQ: spouse relationship 2.06 2.39 2.27 <.0001 0.3655 0.0515 <.0001 <.0001 0.41 -0.14 0.26
SPSQ: health 2.53 2.88 3.08 <.0001 0.0725 <.0001 <.0001 <.0001 0.43 0.26 0.71
Child behaviour
Difficultness, Bates, means (1-7) 3.51 3.7 3.91 0.0038 0.0934 0.0001 <.0001 0.0068 0.22 0.24 0.49
Child's mobility very/rather difficult to handle, % 5.8 8.2 17.5 0.1786 0.0296 0.0017 0.0015 0.0282
1 Low PD: N=856 (843-853). Medium PD: N=249 (244-249). High PD: N=63. Due to missing values, the numbers varied between different analyses.
2 Statistical methods: Student's t test (pairwise comparisons low-medium, medium-high, low-high, DF=1), ANOVAs (comparisons across all PD groups low, medium, high, DF=2), X2 and Fisher's exact test (percentages).
3 Adjusted for parity (first-born child vs. others), child gender, marital status (single vs. others). Statistical method: multiple logistic regressions with dichotomised variables, merging medium and high PD into one category. For spouse relationship stress, only mothers with a partner were included, and marital status was not included as a predictor in the logistic regression. N for the spouse relationship stress variable: low PD 806, medium PD 221, high PD 53.
4 Cohen's d.