Objective To evaluate the total, and direct effects of vitamin D, measured by circulating 25-hydroxyvitamin D [25(OH)D] levels, on GWG after adjustment for confounding variables, and then assess the indirect effects by demonstrating the role of gestational age at birth as a mediator in this association. Design A secondary analysis of data collected in a screening program in pregnancy. Setting and population Data collected in “Khuzestan Vitamin D Deficiency Screening Program in Pregnancy” was used for the present study; it was included the data of 900 pregnant women referred to the health centers of Shushtar (Khuzestan Province, Iran), whose vitamin D status during the third trimester of pregnancy was available. Methods A mediation analysis was applied to detect the causal relationship between serum level of 25(OH)D, covariates (maternal age, parity, and baseline maternal weight), mediator (gestational age), and outcome (GWG). Main outcome measures The main outcome measure of the study was gestational weight gain. Results The adjusted total effect of vitamin D on GWG was estimated 0.0699 (95%CI: 0.0537, 0.0849; P=0.000). Although, an adjusted direct effect of vitamin D on GWG was not statistically significant, the adjusted indirect effect of this micronutrient on GWG by considering gestational age as a mediator was found to be significant [0.059 (95%CI: 0.048, 0.0708; P=0.000)]. Women with severe vitamin D deficiency had the lowest speed as compared to moderate and normal levels. Conclusion This study shows that maternal vitamin D status affects the gestational weight gain by reducing the risk of preterm delivery.

The aim of this study was to design a decision-making questionnaire for selection of prenatal care provider and determine its psychometric properties. Design: The present study is a mixed-method exploratory research Setting: Three maternity hospitals in Shiraz, Iran. Population: In a sample of 300 low-risk pregnant women, we examined the factor structure, reliability, and validity of the CPCP. Methods In the qualitative phase, were selected 23 pregnant women as well as 10 midwives and gynecologists. The samples sat a semi-structured individual interview. In the next step, the questionnaire items were designed based on the results of the qualitative phase and a review literature. In the quantitative phase, face validity, content validity, construct validity, internal consistency and stability were used to investigate the psychometric properties of the CPCP-60 questionnaire. Results: developed questionnaire consisted of 74-item which were reduced to 60 items after the face and content validity was determined qualitatively and quantitatively. The Exploratory factor analysis results revealed the professional skills, communication skills, personal characteristics of prenatal care providers, and characteristics of pregnancy and childbirth centers which accounted for 60.52% of the total variance. Cronbach’s alpha coefficient (0.947) and test-retest (0.951) indicated excellent internal consistency and stability of the questionnaire. Conclusion: Since the designed questionnaire of CPCP-60 is a valid and reliable instrument commensurate with the cultural conditions of society, it can be used in research and clinical settings to assess the pregnant women’s decision making for selection of prenatal care providers in Iran.