Unfavourable beliefs about oral health and safety of dental care during pregnancy: a systematic review

We conducted an electronic search using four databases, PubMed, Scopus, CINAHL, and MEDLINE (Ovid) in May 2022. The search was updated in January 2023. We also conducted forward and backward citation tracing for included articles to locate relevant articles missed from this database search. The search terms were a combination of keywords and controlled vocabulary. The search strategy for all four databases is provided in Additional file 2.

The titles and abstracts of all articles identified through database searching were imported to COVIDENCE. It is a web-based systematic review program which facilitates most of the evidence synthesis steps including citation importing, screening, quality assessment, and data extraction [16]). Two reviewers (YMK and NMZ) independently performed the level 1 (title and abstract) screening. Subsequently, the full texts of the articles included after level 1 screening were uploaded to COVIDENCE for the purpose of full-text screening (level 2) which was independently conducted by the two reviewers based on the eligibility criteria (described below). Disagreements for both screening levels were solved through a discussion and reaching a consensus. For forward and backward citation tracing, all references and citing articles of the included studies were again added to COVIDENCE and the above screening steps were performed on them in the same way.

The inclusion criteria were: 1) the study population was pregnant women or mothers of children under 6 years of age (as it is suggested that prenatal information can be accurately retrieved with a recall span of up to four to six years after delivery [17]); 2) the study was a primary investigation, regardless of study design and year of publication; 3) the article was written in English; 4) the study assessed beliefs about at least one of the impacts of pregnancy on a mother’s oral health; oral health on pregnancy; and dental treatment on pregnancy/child’s health. Further, because the focus of this search was unfavorable beliefs during pregnancy, a study was only included if it included statements referred to as such. The original labelling of such statements in the source manuscript may have been “misbeliefs”, “myths” and/or “false information”, but the labelling of the truth or false nature of such beliefs is largely subjective. Therefore, we have used the term “unfavorable beliefs” as a cumulative term throughout this paper.

The exclusion criteria included: 1) only assessed the knowledge of pregnant women regarding the child’s oral health and 2) assessed the beliefs or knowledge of dentists, midwives, gynecologists, and other health care providers.

Data were extracted by one reviewer (YMK) and then verified by a second reviewer (NMZ) using a standard form on Microsoft Excel (Version 16.70). The main collected data pertained to the studies’ characteristics including author, year of publication, country and region, study design, population, data collection tool, sample size, and response rate. Data on statements identified as misbeliefs and the prevalence of the participants believing in each statement were also extracted. Risk of bias in each study was assessed by utilizing five domains of the CLARITY tool, 1) representativeness of the source population, 2) adequacy of the response rate, 3) the proportion of missing data, 4) comprehensiveness, clarity, and face validity of the survey, and 5) reliability and construct validity of the survey [18].

Since the main purpose of this study was the identification of common unfavourable beliefs about oral health and dental service utilization during pregnancy, data were synthesized through narrative discussion. According to the objectives of this review and due to the wide variety of reported beliefs in the included studies, no meta-analysis could be undertaken. More importantly, the included studies were descriptive in nature and provided no further information than the range and/or the prevalence of the existing unfavourable beliefs among different populations of pregnant women.

Table 1 summarizes the characteristics of the 45 studies which were included. All studies were cross-sectional in design. Sixteen studies used interviewer-administered questionnaires as a tool for data collection, two [11, 19] conducted semi-structured focus groups and interviews, and the other 29 studies gathered data using self-administered questionnaires. Six studies were qualitative [11, 19‐23]. The oldest study was published in 1984 [24], and the newest ones were published in 2022 [25‐29]. Sample sizes ranged from 19 in a qualitative study [21] to 801 in a quantitative study [29].

Figure 2 shows the summary of findings from the risk of bias (RoB) assessment of the included studies. Only two studies [35, 56] had a low RoB in all five domains. A domain was marked as “No information” for a study if the related information was not exactly provided by the authors. The “probably yes” and “probably no” answers were combined and marked as “Intermediate” risk of bias. The “comprehensiveness, clarity, and face validity of the survey” and “reliability and construct validity of the survey” were the most common risks of bias with 16 (36%) and 13 (29%) of the studies having a high RoB in these domains, respectively. 16 (36%) studies did not provide information about the sampling method 21 (47%) studies recruited their samples through non-random (consecutive, convenience, and purposive) sampling, resulting in an intermediate risk of bias. Almost half (53%) of the studies did not report the response rate; however, this rate was more than 75% in 14 (31%) of the studies. Regarding missing data, 33 (73%) of the studies had a low risk of bias. A detailed RoB assessment of each study is presented in Additional file 3.

More than one hundred uniquely worded unfavourable beliefs were identified. However, many of these are equivalent and simply differently worded. These words can be grouped into four main categories of unfavourable beliefs about: 1) utilization of dental services (Table 2); 2) specific dental treatment procedures (Table 3); 3) oral health conditions (Table 4); and 4) other oral health-related unfavourable beliefs (Table 5). Due to the variety of how different studies worded their questions and labelled statements (as knowledge, attitude, misbelief, perception, myths, view, and misconception), for consistency purposes, the word “unfavourable beliefs” is used throughout this review. The original statements and their prevalence can be found in Additional file 4.

Twelve studies reported concerns about radiation exposure in dental clinics. The study by Murphey [22] identified a belief regarding the harmfulness of dental X-rays to the fetus, which was considered to be a false belief. Similarly, a qualitative study by Bahramian and colleagues [11] identified the belief that radiography could cause miscarriage; the authors of the study considered it to be a “misbelief”. Other studies cited in Table 3 reported the prevalence of unfavourable beliefs regarding adverse pregnancy outcomes due to dental X-rays exposure which ranged from 31% [50] to 93% [27].

Eight studies reported the unfavorable belief among pregnant women that dental anesthesia was hazardous, with the prevalence of this belief ranging from 25% [12] to a high of 95% [45] of participants in different studies. In a study by Bahramian et al. [11], an interviewee believed that anesthesia causes miscarriage. In four studies, participants were reported to believe that medications pertinent to dental treatments, such as pain medications, should be avoided because of harm to the fetus or mother [11, 20, 27, 45].

Seven studies discussed dental extraction during pregnancy. One of the common beliefs identified by Jain et al. [12] and Akbari et al. [29] was that tooth extraction causes miscarriage. In one qualitative study [23], and four other quantitative studies, pregnant women believed that dental extraction is contraindicated and harmful. When reported, the prevalence of the belief that extraction is a harmful dental practice ranged from 6% in a study by Assery [42] to more than 80% of the respondents in three other studies [26, 28, 51].

Routine dental treatment procedures such as dental fillings, calculus removal, and periodontal therapy were perceived to be unsafe by participants in four quantitative studies [26, 28, 42, 45]. In qualitative studies, concerns about bacterial infection of the baby due to bleeding from dental check-ups were also stated. Some participants expressed potential environmental sources of harm including dental clinics exposing their fetuses to bacteria, materials and chemicals used in dental offices [20, 22].

Eighteen studies discussed tooth loss and pregnancy. In five studies participants were specifically asked if they held unfavourable belief in the given statement/s “a tooth per child” [24, 30, 35, 36, 59] while in two other qualitative studies, participants indicated an unfavourable belief that “at least one tooth is lost or destroyed in each pregnancy” [11, 21]. This belief was assessed through various other statements as shown in Table 4. The prevalence of beliefs about tooth loss were notably different; in a study by Kaba et al. in Kenya [28] 86% of participants unfavourably believed that pregnancy causes tooth loss while in the study by Awasthi et al. [58], no one attested to this belief.

As shown in Table 4, in 10 studies, participants believed that pain in gums, bleeding or swollen gums are normal occurrences and need no special consideration [12, 28, 29, 39, 45, 53], or that pregnancy is a cause of periodontal problems [24, 34, 42, 53, 58].

Although not so common, some women perceived toothache [20, 21, 45] or tooth decay as normal occurrences in pregnancy [24, 42, 45].

Unfavourable beliefs about oral health can have consequences such as avoidance of dental treatment and dental service utilization [10]. Dinas et al. found that women who considered dental treatment to be unsafe during pregnancy were less likely to visit a dentist [31]. Unfavourable beliefs may also contribute to oral health conditions which can be due to dental care avoidance or improper oral hygiene [58, 83]. In a study by Jain et al. [12], a significant positive correlation was observed between having dental conditions (conditions were not specified by the authors) and beliefs pertaining to avoiding dental visits during pregnancy. Delayed dental care-seeking behaviour can lead to the progression of dental conditions and complications such as odontogenic abscess, facial cellulitis, severe pain, and tooth loss [80, 84]. These complications can adversely impact pregnancy outcomes and the overall well-being of pregnant women including nutrition, sleep time, and mental health [66, 85].

Our review identified that oral health literacy was directly associated with presumed myths and unfavourable beliefs [86]. Therefore, it is important to engage pregnant women in delivering evidence-based oral health education [87]. Pregnancy is the best time to bring about positive behavioural change in women [88]. A study by Erchick et al. [89] concluded that pregnant women were more likely to adopt their oral hygiene intervention as it has a direct impact on the health of the fetus and newborn. Although no studies have examined the association between the level of oral health knowledge and the source of such knowledge during pregnancy, some studies reported that culture, elder family members and peers from participants’ networks, including friends, are the origins of such beliefs [12, 22, 23]. Surprisingly, healthcare professionals have also been reported as a source of misinformation regarding oral health [90, 91]. This finding highlights the importance of integration of primary oral healthcare knowledge and prevention in the primary healthcare model. A study by George et al. [92] in Australia engaged midwives in delivering oral health education to pregnant women. Similarly, Ragade et al. [93] and Adeniyi et al. [94] actively engaged primary healthcare workers in preventative oral health interventions in the United States and Canada, respectively. Integration of oral health education within the primary care delivery model can significantly help to reduce and dismantle commonly held misbeliefs during pregnancy [92]. The wide range of existing unfavourable beliefs regarding oral health during pregnancy emphasizes the importance of integrating preventative and primary oral healthcare services in routine prenatal care. Furthermore, it underscores the importance of enhancing the oral health expertise of primary healthcare practitioners and disseminating this knowledge to expectant mothers through oral health educational interventions during prenatal care sessions. These interventions should be focused on the individualized and risk based oral health needs of pregnant women and their soon to be born babies.

Several limitations were identified in the reviewed studies. In most of the studies, authors did not distinguish between knowledge and attitude which resulted in using these two concepts interchangeably. Further, a quarter of the included studies did not elaborate on the process of developing their survey questionnaires and the sampling method was not reported in almost one-third of the studies. Only seven studies had a random sampling method which ensured the representativeness of the sample while a majority of the studies incorporated a convenience sampling method which limits the external validity of the findings. Further, recruiting the subjects from a specific clinic or hospital, either public or private, resulted in a homogenous sample.

Although this study is the first of its kind to attempt a systematic review of commonly held oral health beliefs during pregnancy and to discuss the contributing factors and consequences, the findings should be considered in light of the limitations. Since our review included both qualitative and quantitative studies, we were unable to separate our findings based on the study design. Some beliefs were only reported by a single individual in a qualitative study henceforth the generalizability of these misbeliefs is not guaranteed. The prevalence of the beliefs was not compared according to the country or region; however, this objective did not seem feasible given the large variety of reported beliefs. Further studies could assess differences in beliefs among pregnant women from various cultures and with different socioeconomic statuses. Furthermore, this review limited the population to pregnant women and new mothers; unfavourable beliefs among healthcare providers could be systematically explored in future studies to see if any implementation for improving the oral health knowledge of these groups is required.