The most important objective of dental health care in pregnancy is to establish a healthy environment through adequate plaque control by brushing, flossing and professional prophylaxis including scaling, root planing and polishing 1. Dental treatment can be safely provided at any time during pregnancy 2 allowing pregnant women to achieve an optimal level of dental health throughout their pregnancy.

Periodontal disease may present as gingivitis or periodontitis. Gingivitis is an inflammation of the soft tissues surrounding a tooth or gingiva not causing loss of periodontal attachment, whereas periodontitis causes inflammation and destruction of supporting tissues around the teeth 2. Periodontal disease has the potential to affect pregnancy outcomes. A systematic review of 25 studies (13 case-control, 9 cohort and 3 controlled trials) has demonstrated that periodontal disease may be associated with adverse pregnancy outcomes in humans 3. Although some observational studies have indicated a significant association of periodontal disease with adverse pregnancy outcomes 45, others have not 67.

Oral tissues are known to be affected by pregnancy with the most frequent and greatest changes occurring in the gingival tissue 8. Pregnant women may be more susceptible to periodontal disease since higher concentrations of oestrogen and progesterone can induce hyperaemia, oedema and bleeding in periodontal tissues 9, increasing the risk of bacterial infections. The incidence of periodontal disease has been positively correlated with lower educational achievement and lower socio-economic status 91011.

Periodontal disease is both preventable and treatable. Controlling plaque by brushing, flossing and professional prophylaxis, including scaling and root planing, all help to achieve good dental health in pregnancy 1. There is, however, minimal information available on women's understanding of dental hygiene and whether pregnant women comply with current oral health strategies.

The aims of this survey were to assess women's knowledge and experiences about dental hygiene in pregnancy in Australia and assess the self-care practices of pregnant women in relation to their oral health. We hypothesised socio-economic status and educational qualifications would influence a woman's knowledge and choices about oral health in pregnancy.

All women who gave birth to a live born infant at the Women's and Children's Hospital, Adelaide, over a five month period were eligible for the study. Women who gave birth to an infant with a major congenital abnormality, had a perinatal death or who needed an interpreter were ineligible. The study was approved by the Hospital Research and Ethics Committee.

A questionnaire was developed to assess women's dental health knowledge, oral health experiences and preferences over the preceding twelve months and provide information on their educational status. Fifty questions were selected from three validated questionnaires; the National Dental Telephone Interview Survey (NDTIS) 12, Oral Health Impact Profile (OHIP) 13 and The World Health Organization's Comparing Oral Health Care systems; a second international collaborative study (ICS II) 14. Additional questions included information in relation to awareness of periodontal disease and plaque, use of a family dentist, advice about dental health requirements during pregnancy, history of bleeding gums and what, if any, actions were sought to treat perceived gingival problems. Relevant clinical information, such as pregnancy care, parity, ethnicity, age and residential location, was sourced from the medical records of the woman and her infant.

Eligible women were approached on the postnatal ward and given a study information pamphlet. Women who gave informed written consent were asked to complete the questionnaire and place it in the reply paid envelope. Women who failed to return the questionnaire within three weeks were posted out a reminder letter and another questionnaire. Women who did not return the questionnaire were telephoned as a reminder.

Analysis was performed with SAS 15. Descriptive statistics were reported as well as cross-tabulations by age, parity, education and socio-economic status. Inference on the cross-tabulations was performed, using chi-square tests to test for general association and Mantel-Haenszel chi-square tests to test for linear association where appropriate.

In order to show a significant difference between women with a tertiary education compared with women without a tertiary education who brushed their teeth at least daily, a sample size of 374 women was needed. This was calculated estimating a difference of 9% between groups based on 95 per cent of mothers who had a tertiary education and 86 per cent of mothers who did not have a tertiary education (p < 0.05; 80% power) would brush their teeth at least daily. The sample size was adjusted upward to allow for a 14 per cent non-completion rate.

During the enrolment period a total of 505 eligible women were approached; 445 (88%) consented and 388 (87%) returned their questionnaire. Although small numbers of responses were missing from some questions, a denominator of 388 was used to calculate results (except in the cross-tabulation in Table 1).

In this survey of recently pregnant mothers, most women were knowledgeable about dental health but only a small percentage knew about periodontal disease.

Over half of the women surveyed revealed they did not attend the dentist during the previous twelve months, and only 30% attended during their most recent pregnancy. The majority indicated they required a dental check-up with just under half believing they needed scaling and cleaning of their teeth. The results from this survey are consistent with studies conducted in the United States of America where more than 50% of pregnant women did not receive dental care during their most recent pregnancy 1116. This raises serious concerns about dental care-seeking behaviours as most adults would be due for their routine dental visits during any nine-month period, and pregnant women may need extra periodontal care 1. Over half the women surveyed (65%) recalled being informed of the dental health requirements in pregnancy yet they did not attend the dentist.

Cost of dental care may have an impact on the dental seeking behaviours of pregnant women in Australia. In Australia women must have insurance or be prepared to pay to cover private dental treatment or be placed on a waiting list to seek free treatment in the public system. This could be an independent risk factor whether pregnant women seek dental advice and treatment or not 17.

Many women surveyed reported signs suggestive of periodontal disease during the previous twelve months by the occurrence of bleeding, sore gums and a persistent bad taste in their mouth. Our findings confirm bleeding and sore gums are common among pregnant women 914. Although women indicated they had suffered discomfort from sore and bleeding gums and had bad taste in their mouth only a small proportion chose to attend the dentist.

This survey highlights important gaps in dental knowledge and practices in women, particularly those with lower educational achievements and lower socio-economic status. Better knowledge of dental hygiene and practices were found in women who had some form of tertiary education and from a higher socio-economic status. Similar results were found in the recent systematic review of 25 studies 3. Failure to attend a dentist on a regular basis and lack of understanding about the importance of maintaining oral hygiene may be because some women simply cannot afford to maintain an adequate level of dental hygiene or regular dental visits. Educating and motivating women to maintain good oral hygiene and providing affordable dental health care is fundamental in reducing dental disease. Improving dental education may need to become a priority in antenatal care to educate women at risk of the importance of maintaining oral health 18.

Although this study has the limitations of relying on self-reported data and therefore is subject to biases inherent to this method, such as misclassification of the question being asked, most women completed the study within one to three days of birth therefore recall bias should be minimal concerning their pregnancy. Recall bias is clearly likely to be greater when recalling information from the previous twelve months. Unfortunately women who required an interpreter to complete the questionnaire were excluded from the study as funding was not available. Therefore the results from the survey cannot be extrapolated to women with a non-English speaking background, although in our population these women represent less than 5% of the total population.

Postnatally, most women had some knowledge of dental disease. However, this survey showed associations between lack of knowledge of dental health and dental hygiene with women with lower educational achievements and women who resided in lower socio-economic areas. Although most women appear to be informed about dental hygiene practices the majority did not attend the dentist during the previous 12 months. Whether better education on dental health in pregnancy can lead to improved dental practices, improved health and better pregnancy health outcomes requires further investigation.

The author(s) declares that they have no competing interests.

NT designed and administered the survey, under the supervision of CC. All authors interpreted the data and wrote the paper.