Pregnant women (vs the general public) may be expected to be more aware and knowledgeable about cCMVi due to their interactions with healthcare providers and also heightened sensitivity towards information about diseases in children. In this study, we found low awareness of cCMVi among pregnant women (16.1%) and the general public (10.2%), and limited related knowledge among those who were aware of cCMVi. Considering the prevalence of cCMVi in newborns (globally, 0.64%; Japan, 0.26–0.50%) [1,2,3,4,5], the possibility of serious cCMVi-related sequelae [9,10,11], and the fact that there is no approved vaccine available, practicing behaviors that may reduce CMV transmission is the best available and effective method to reduce the risk of cCMVi . Importantly, the level of cCMVi knowledge among pregnant women, for whom this information is most important, was not very high when compared with the level of knowledge among the general public, indicating a need for improved knowledge among pregnant women. A small percentage of pregnant women practiced behaviors that can prevent CMV transmission; however, pregnant women who were aware of cCMVi considered that such practices would be easy to implement.
Several surveys have reported rates of CMV awareness that were somewhat higher than we found in this study (pregnant group, 16.1%; general group, 10.2%); this is at least partly attributable to the populations surveyed. For example, awareness was 60% among pregnant women who were seen at two hospitals in France, including a teaching hospital with an active CMV prevention policy, and 52.5% among surveyed University of Milan attendees [17, 20]. A more recent study conducted at a single hospital in Rome reported an awareness rate of 59.1% . Regarding these studies reporting relatively high awareness, it is important to note that the level of education is relatively high in some of the areas in which the participating institutions are located, and active education and screening on cCMVi are common. Lower rates of CMV awareness have been reported for studies conducted on more generalized populations in Japan (18%), the USA (20–22%), and the Netherlands (12.5%) [16, 19, 21, 22]. We found that current cCMVi awareness in pregnant Japanese women was similar to that reported by Morioka et al. nearly 10 years ago . A more recent study conducted in Japan reported that 31.9% of pregnant women (non-healthcare professionals) were aware of CMV . Although the latter study reported higher awareness, it should be noted that both Japanese studies were conducted at a single institution. Nonetheless, awareness remains inadequate. It seems that educational efforts for cCMVi have not substantially increased in the years between the studies.
Although pregnant women in the current study were generally practicing good hygiene (i.e., washing hands, gargling, avoiding crowded places, avoiding people with a fever or rash, and cooking meat thoroughly), most (66.7–72.1%) were not practicing behaviors that might specifically prevent CMV transmission (i.e., washing hands after diaper changing, avoiding kissing young children on the mouth, and not sharing food, drink, or cutlery with young children). Similarly, a study conducted in the Netherlands by Pereboom et al. reported that pregnant women had a high incidence of risk behavior . Among women with children < 5 years old in their home, 91.3% reported sharing of utensils or cups with children, and 69.4% did not wash their hands after changing a diaper at least once during their pregnancy.
Overall, our study found that pregnant women in Japan had less knowledge about CMV transmission routes, long-term outcomes of cCMVi, and behaviors that reduce the risk of CMV transmission compared with similar survey studies conducted in other countries. It should be noted that, in some cases, the populations surveyed in the overseas studies differed somewhat from our study population. In our study, nearly half of the pregnant women who were aware of cCMVi had no knowledge about any of the routes of CMV transmission, and < 30% knew of each correct transmission route. Knowledge on CMV transmission was higher in the Italian study of university attendees. Among those who were aware of cCMVi, only ~ 15% had no knowledge about any of the routes by which CMV is transmitted, and approximately 40–70% were aware of each correct transmission route . As noted above, however, the differences in study results may be attributable to the less generalized population surveyed in the Italian study.
Knowledge of the long-term outcomes of cCMVi was also low (1.2–22.1%). Only 22.1% of pregnant women in our survey were aware of hearing loss, while 42% (France, pregnant women), 48% (US, women), and > 50% (University of Milan attendees) of those surveyed outside of Japan were aware of this outcome [17, 19, 20].
Knowledge of preventative behaviors was reported for several of the overseas studies. Over 80% of the pregnant women surveyed in France  and approximately 50–75% of surveyed University of Milan attendees  were aware of at least one appropriate preventative behavior. Although this calculation was not done in our study, we instead found that 36.0% of pregnant women who were aware of cCMVi answered ‘Do not know’ when asked which listed behaviors could prevent CMV transmission, similar to the proportion in the general group (22.4%). Further, fewer than half of the pregnant women had known about each preventative behavior. Thus, our findings confirmed that preventative behaviors should be one topic of focus in the education of pregnant women.
Although knowledge and implementation of preventative behaviors were low, most pregnant women who were aware of cCMVi considered preventative behaviors to be easy to implement (73.3–95.3%). This suggests that the practice of preventative behaviors may increase dramatically if awareness and understanding of CMV transmission routes, preventative behaviors, and long-term outcomes of cCMVi are increased. Preventative behaviors would be particularly important for pregnant women who are in regular contact with infants, including those with older children who attend nursery school or kindergarten, those who work in a nursery school or kindergarten, and those who work in pediatric wards as health care providers. As such, increasing education and awareness of preventative behaviors among these women should be prioritized.
For the first time, the awareness among pregnant women of information leaflets on diseases transmitted from mother to child was reported and found to be quite limited. Low awareness about the leaflets among health care professionals may be one possible explanation for the low awareness among pregnant women, as healthcare providers are often a primary source of information for them . The results of our survey highlight the need to increase activities to raise awareness among pregnant women. Efforts by healthcare providers to educate pregnant women should be enhanced and the daily activities of modern-day pregnant women should be carefully considered to help facilitate the development of better methods for dissemination of this information. Approaches that can target specific populations of pregnant women should also be explored.
The overarching finding of this study was that there is a need to improve awareness and knowledge of cCMVi among pregnant women in Japan. Towards this goal, healthcare professionals should stress the long-term outcomes of cCMVi and emphasize that they can be prevented by avoiding behaviors associated with CMV transmission during pregnancy. Additionally, more comprehensive strategies need to be evaluated, including providing incentives for the education of pregnant women and for antibody screening. As previously noted, the lifestyle and behavior of pregnant women should also be carefully considered when evaluating potential educational strategies. For example, mobile devices (i.e., handheld computers) are increasingly a part of daily life and may be considered as a potential platform to communicate information related to cCMVi.
This study has several limitations. First, the generalizability of the findings may be limited because online panelists may have different characteristics from the general population and also due to non-response bias. For example, the distribution of trimesters in pregnant women in our study, particularly the relatively low proportion of women in the first trimester compared with the proportion of women in the second or third trimester, may have introduced bias. The first trimester includes a period of time when the pregnancy is unconfirmed, and many pregnant women may be especially sensitive during the first trimester and, as such, may have refrained from responding to our survey, considering the topic. Second, the questionnaire was newly developed for the survey and was not validated; however, it was partially based on, and consistent with, several prior published studies [16, 17, 20, 25]. Therefore, the results should be interpreted with caution as this questionnaire had some limitations, including ambiguity in the knowledge questions (e.g., changing diapers does not necessarily constitute a direct risk of infection, whereas contact with infected urine is associated with an increased risk of infection). Finally, the results were subject to bias due to correct random guesses, which may have resulted in overestimation of awareness or knowledge.