IntroductionAssessing and understanding pregnant women's knowledge and perceptions of COVID-19 infection and its implications for pregnancy is critical for meeting their specific needs. However, currently, there is a lack of validated questionnaires to assess this issue. This study aims to determine the validity and reliability of the Knowledge and Attitude on the effect of COVID-19 Infection on Pregnancy (KACIP) Questionnaire Among pregnant women in Malaysia. Materials and methodsKACIP was developed using the Health Belief Model (HBM), extensive literature review and expert judgement. The questionnaire underwent a sequential validation process, content validation, face validation, Exploratory Factor Analysis (EFA) and internal consistency reliability-based Cronbach's alpha statistic. For the construct validation, a cross-sectional study was conducted among 200 pregnant women attending the antenatal clinic at Universiti Sains Malaysia Hospital. ResultsThe final KACIP consisted of two sections; Knowledge and Attitude on COVID-19 infection effect on pregnancy. The Knowledge section comprises three domains (13 items) and the Attitude section has two domains (9 items). Preliminary KACIP demonstrated a high item Content Validity Index and Face Validity Index. The Kaiser-Meyer-Olkin values for the Knowledge and Attitude sections were 0.785 and 0.783 respectively and had a significant p-value of <0.001 for Bartlett's test of sphericity. Factor analysis showed that KACIP had adequate psychometric properties with acceptable factor loadings and Cronbach alpha values. ConclusionsThis validation and reliability study showed that KACIP is a valid and reliable questionnaire to assess the Knowledge and attitude towards the impact of the COVID-19 infection on pregnancy among pregnant women in Malaysia.