According to the general health literacy index, more than half of the mothers had a problematic health literacy. Only one-third of study participants had sufficient or excellent health literacy (Fig. 1).

Histogram of the general maternal health literacy index

Individual domains of health literacy were found to be problematic or inadequate in more than half of the respondents in the areas of health care, disease prevention, and health promotion (Fig. 2).

Histograms of indices of health care, disease prevention, and health promotion

Tables 1 and 2 present and compare estimates of maternal health literacy. With regard to general health literacy competences, the health care index is the highest (mean 32.76 ± 5.86) and the health promotion index is the lowest (mean 29.20 ± 7.16). The means of all these health literacy indices are statistically significantly different (F = 91.257, p < 0.001), health care indices are significantly higher than disease prevention and health promotion indices, and disease prevention indices are significantly higher than health promotion indices (p < 0.001).

According to the mothers' health information processing scores, their ability to understand health information was the greatest (index mean 33.30 ± 6.57), while the ability to obtain health information (index mean 29.85 ± 8.37) and to evaluate health information (index mean 29.61 ± 6.91) were the lowest. The indices of the ability to obtain health information and the ability to evaluate health information did not statistically significantly differ (p > 0.05); the index of ability to understand health information was statistically significantly higher than all other indices: of ability to obtain, evaluate, and apply health information (p < 0.001); the index of ability to apply health information was significantly higher than the indices of ability to obtain and evaluate health information.

Further analysis was done to investigate the associations between mothers' socio-demographic characteristics (age, education level, marital status, pregnancy planning, number of pregnancies) and their health literacy indices.

The correlation analysis did not show any statistically significant relationships between mother's age and their health literacy competency indices or health information processing indices (p > 0.05), but revealed a weak, statistically significant association between the mother's education level and the indices mentioned above: the more educated a woman is, the higher is her general health literacy index (r = 0.298, p < 0.001), health care, disease prevention, health promotion indices (r = 0.198, p < 0.001; r = 0.345, p < 0.001; r = 0.206, p < 0.001) as well as the indices of ability to obtain, understand, evaluate and apply health information (r = 0.278, p < 0.001; r = 0.332, p < 0.001; r = 0.184, p < 0.001; r = 0.195, p < 0.001) (Table 3).

According to the results of the Student’s t-test (Table 4), the indices of health care, disease prevention, health promotion, and overall health literacy index of primiparous women were not statistically significantly different from multiparous women (p > 0.05). However, a comparison of their health information processing indices showed that women who give birth not for the first time have significantly greater ability to evaluate actual health information than those who give birth for the first time (index means accordingly 30.22 ± 6.82 and 28.72 ± 6.97) (p < 0.05).

One-way ANOVA comparison of subjects with one, two, three, and more children revealed statistically significant differences in their overall health literacy competence (p < 0.001), in individual health literacy domains (p < 0.01), and in the four aspects of health information processing (p < 0.01) (Table 5). In order to carry out a more detailed analysis and to determine which of these groups perform differently from the others, the results of the pairwise comparison of the post-hoc LSD test were assessed (Table 6). It showed that for women with one, two, and three children, the majority of health literacy indices were similar (p > 0.05), only their health care index and their capacity to evaluate health information indices differed statistically significantly (p < 0.05): women with three children had statistically significantly higher health care and health information evaluation indices than women with one or two children (p < 0.05); women with two children had statistically significantly higher health information evaluation indices than women with one child (p < 0.05). Women with 4–6 children were the most prominent of all the women surveyed: all of their health literacy indices were statistically significantly lower than those of women with one, two, or three children (p < 0.05). The difference in educational attainment between women with 4–6 children and women with fewer children was computed to further understand the probable causes of these discrepancies. The first group of women had a statistically significantly lower level of education (p < 0.001) and none of them had received maternity skills training.

There was no statistically significant difference in the mean of health literacy and health information processing indices between married women and unmarried women living with a partner (p > 0.05).

Subjects who had received maternity skills training (compared to those who had never received such training) had statistically significantly higher indices of health care, disease prevention, health promotion indices, and the overall health literacy index (p < 0.05; p < 0.001; p < 0.001; p < 0.001); their indices demonstrating the ability to obtain, understand, and evaluate pertinent health information were statistically significantly higher as well (p < 0.001; p < 0.001; p < 0.05) (Table 7). A comparison of these two groups' educational attainment revealed that the overall educational attainment of women who had not undergone maternity skills training was statistically significantly lower (p < 0.001).

Subjects who had planned their last pregnancy (compared to those who did not) had statistically significantly higher scores on the health care, disease prevention, health promotion indices, and the overall health literacy index (p < 0.001; p < 0.01; p < 0.01; p < 0.001); they also had statistically significantly higher indices demonstrating their ability to obtain, understand and apply relevant health information (p < 0.001; p < 0.001; p < 0.001) (Table 8).