Validity and Reliability of the Antepartum Gastrointestinal Symptom Assessment Instrument.

OBJECTIVE

To examine the psychometric properties of the nine-item Antepartum Gastrointestinal Symptom Assessment (AP-GI-SA) instrument.

DESIGN

Single-group prospective design.

SETTING

Urban prenatal clinic serving a diverse population.

PARTICIPANTS

Convenience sample of 45 pregnant women.

METHODS

Participants completed the AP-GI-SA before a scheduled prenatal care appointment. We used Bayesian structural equation modeling to evaluate the construct validity of the scale and assessed known-groups validity. We assessed reliability through maximal reliability coefficient estimate and measured internal consistency with Cronbach's alpha coefficient.

RESULTS

Participants completed the instrument in 2 minutes or less. Construct validity was supported by confirmatory factor analysis (posterior predictive p value = 0.49, gamma-hat = 0.970, and root mean square error of approximation = 0.065), which indicated that the single-factor model is a plausible data-generative model for GI symptoms. The maximal reliability coefficient of 0.75 and Cronbach's alpha coefficient of 0.67 supported reliability. Average AP-GI-SA scores were the highest for women in the third trimester. Of all nine GI symptoms, heartburn in the third trimester received the highest score.

CONCLUSION

Our findings provide preliminary support for the validity and reliability of the AP-GI-SA. The instrument may be used as a measure in intervention studies where GI symptoms of pregnancy are an outcome. The AP-GI-SA could also be useful in clinical settings to quickly evaluate GI symptoms.