A total of 716 women were contacted to participate in the study, there was a 44% response rate with 315 women included in the analysis, the majority of whom were recruited from London clinics (251, 80%) (Supplementary Table 9). The mean age was 35 years (SD 7.1) (Table 1) and the median pre-pregnancy eGFR was 64 (IQR 56) mL/min/1.73m2. Ninety-four (30%) were renal transplant recipients, 53 (56%) of whom were pre-emptive. Over half had at least one pregnancy (186, 59%) and 46 (14.6%) were currently trying to conceive at time of participating. Most women reported pregnancy being important or very important to themselves (234; 74.3%) and to their family (211; 67%).

The majority of women had not attended pre-pregnancy counselling (206, 65.4%). Those who had attended had more advanced CKD (median pre-pregnancy eGFR 54 mL/min/1.73m2 versus 68 mL/min/1.73m2, p = 0.007), perceived greater pregnancy risk (mean overall perceived pregnancy risk score 51.7 versus 42.5, p = 0.001) and had higher education (71.3% versus 54.4% university graduates, p = 0.001) (Supplementary Table 10).

The subscales of perception of pregnancy risk questionnaire (PPRQ) were strongly correlated (r = 0.81). When latent factors were modelled correlation increased (r = 0.90), thus the overall perceived pregnancy risk scale was used in the analysis. Correlations between KDQOL summary scores and the other psychological constructs confirmed that the MCS (r = − 0.75, 95% CI − 79 to − 0.69) and KDCS had strong negative correlations with distress (r − 0.66, 95% CI − 0.73 to − 0.57, p < 0.00). The PCS did not correlate with the psychological attributes measured (r = \(\le\) 0.50) so the PCS was used as the QoL indicator in regression analyses to avoid collinearity with other variables (Supplementary Table 11).

There was a significant difference in the overall perceived pregnancy risk of women with CKD stages one to two (PPRQ mean 38.7, SD = 22.9) and stages three to five (PPRQ mean 53.2, SD = 23.1); t(280) = − 5.6, 95% CI − 19.6 to − 9.4, p < 0.001. There was also a difference in perceived pregnancy risk between women who had received a kidney transplant (PPRQ mean 55.5, SD = 22.5) compared to those who had not (PPRQ mean 41.3, SD = 23.5): t(295) = -5.2, 95% CI − 19.7 to − 8.7, p < 0.001.

Univariate analysis identified older age, pre-pregnancy counselling attendance, greater perceived severity of CKD, previous dialysis, kidney transplantation, clinically relevant proteinuria, and chronic hypertension as significantly associated with higher perceived pregnancy risk. Preserved kidney function, greater perceived quality of life, and being employed were significantly associated with a lower perception of pregnancy risk. Women who perceived their CKD with more negative beliefs, experienced greater anxiety and depression (distress), or reported a perceived greater risk of COVID-19 had increased perceived pregnancy risk (Table 2).

After inclusion of demographic data, psychological attributes and relevant clinical characteristics in the model, pre-pregnancy counselling attendance, greater perceived severity of CKD, more negative illness beliefs and greater COVID-19 risk perception remained significantly associated with greater perceived pregnancy risk (Table 3). There was no association between clinical characteristics and perceived pregnancy risk. Inclusion of psychological variables within the model improved explained variance from 21% (R2 = 0.21, 95% CI 0.13–0.30) to 33% (R2 = 0.33, 95% CI 0.24–0.42). The Wald test was significant (p < 0.001) indicating that psychological attributes significantly contribute to the model of perceived pregnancy risk.

There was no significant difference in pregnancy intentions between women with CKD stages one to two (pregnancy intention mean score = 2, SD = 1.1) and stages three to five (pregnancy intention mean score = 2.1, SD = 1.2); t(303) = -0.5, 95% CI -0.3 to 0.2, p = 0.647. There was no significant difference in pregnancy intentions between women who had received a kidney transplant (pregnancy intention mean score = 2.1, SD = 1.2) compared to those who had not (pregnancy intention mean score = 2.0, SD = 1.1): t(307) =  − 0.4, 95% CI − 0.33 to 0.22, p = 0.697.

In the univariate analyses religious identity, Black or Asian ethnicity, attendance at pre-pregnancy counselling, regarding pregnancy as important to themselves and their families, and greater quality of life were all measurably associated with greater pregnancy intention. Conversely, greater perceived COVID-19 risk, greater distress, and increased parity were associated with avoidance of pregnancy. Clinical characteristics were not associated with pregnancy intention (Table 2).

In the multivariable model, pregnancy counselling attendance, religious identity and regarding pregnancy with greater importance were significantly associated with greater pregnancy intention (Table 4). An increase in number of children, and greater perceived risk of COVID-19 were associated with avoidance of pregnancy. No association was identified between clinical characteristics and pregnancy intention. Inclusion of psychological variables within the model improved explained variance from 33% (R2 = 0.33, 95% CI 0.25–0.42) to 36% (R2 = 0.36, 95% CI 0.28–0.45) with significant Wald test (p = 0.005) indicating that psychological attributes contribute to the model explaining pregnancy intention.

There was no association between perception of pregnancy risk and pregnancy intention (r = − 0.002, 95% CI − 0.12 to 0.11, p = 0.97). No association was consistent in the subgroup analyses amongst: CKD stages 1 to 2 (r = 0.09, 95% CI − 0.08 to 0.25, p = 0.30), CKD stages 3 to 5 (r = − 0.08, 95% CI -0.24 to 0.09, p = 0.35), kidney transplant recipients (r = − 0.1, 95% CI − 0.3 to 0.12, p = 0.38) and non-kidney transplant recipients (r = 0.04, 95% CI − 0.1 to 0.18, p = 0.57).