The awareness of HPV among these young primiparous women was low, as only one third of the participants reported having "ever heard about HPV", despite the fact that the present analysis began 16 days after public news and announcements about the first regulatory approval of one of the HPV vaccines, on June 08, 2006 , and the fact that participants in the present study had relatively high levels of education within the Brazilian context.
Surveys conducted previously and before the regulatory approval of HPV vaccines also showed a low level of awareness of HPV (30-40%) [11–14]. The results of the present study are in line with other recent studies, carried out after regulatory approval of HPV vaccination, that showed limited levels of awareness of HPV. In the United Kingdom and Italy (where HPV vaccine is free of charge for girls of 12 years of age), only about 24% and 30% of respondents, respectively, reported awareness of HPV [15, 16].
In the present study, awareness of HPV was the first question and we did not ask any open questions concerning knowledge of HPV, cervical cancer causes and prevention, or vaccines when the participant was not aware of any of theses subjects, in order to avoid influencing the answers to the open questions or obtaining an answer given correctly by luck, as can occur in studies that use multiple-choice answers.
Only 19% and 7% of the present study participants, respectively, knew that HPV is an STI and that it can cause cervical cancer. Another study, carried out in north-eastern Brazil, assessing young women (16-23 years) showed similar results to the present study: less than 10% of participants acknowledged that HPV might lead to cervical cancer; however, a higher proportion of those women (67%) knew that HPV is sexually transmitted . This difference might be explained by the fact that these women had higher educational levels than women in the present study (61% and 50% respectively had high school education or above). Alternatively, because the authors  used five multiple-choice answers per question, a bias cannot be excluded.
We also studied the relationship between HPV awareness and several factors. The multivariate analysis highlights two factors: having had a previous STI and increasing age remained as factors associated with HPV awareness. Accordingly, some authors reported that increasing age (women 14-24 years)  and having had a personal, familiar, or friendly history of previous STI or cervical cancer were associated with an increased awareness of HPV and accurate knowledge of the HPV-cervical cancer link [13, 14, 16].
Half of all participants reported awareness concerning cervical cancer prevention by cytological test, although a smaller number were aware of how it is performed. The query was intended to estimate how many women were aware, and whether they were able to recognize the differences between the ordinal gynecological test and the cytological tests. Based on our data, just 27% of the young primiparous women were able to recognize the differences.
Other studies regarding cytological tests estimated whether the women were aware of their purpose, and hence are not suitable for direct comparisons. They reported a variety of results (10-89%) concerning the interviewees' awareness of the cytological tests' purposes [11, 16, 17].
In the present study, the awareness regarding vaccines was high, with 74% of the interviewees mentioning their preventative aspect, and 57% of women could identify at least one of the vaccines they had received; that is, they could name the vaccine or the disease which it was intended to prevent.
With regard to the acceptability of the vaccine, despite the inadequate knowledge of HPV and cervical cancer, all participants reported that they would accept vaccination after delivery if the HPV vaccine was available. As other studies have reported, there was a generally favourable attitude toward HPV vaccines; despite the low level of knowledge about the link between HPV and cervical cancer, 91% and 88% of women would agree to receive the vaccine in surveys that found that only 15%  and 38% , respectively, had heard of HPV.
However, it is important to report that the question about the knowledge of vaccines preceded the question about the acceptability of the HPV vaccine, and for the participants who did not know the answer to the first question, one brief explanation on the prevention of illnesses through vaccines and on the HPV prophylactic vaccine was given by the interviewers in the present study.
In fact, the main factor associated with the acceptance of the HPV prophylactic vaccine in studies carried out prior to its approval was the knowledge of the participants concerning the purpose of vaccines [20, 21].
Public acceptance and usage of a prophylactic vaccine are related to the level of knowledge about the disease, which the vaccine will provide protection from . Education about HPV prophylactic vaccines, cervical cancer, and related topics is needed in every country where the vaccine is available.
The main limitation of this study is that 32% of eligible women who were previously interested in participating did not return to the post-natal visit. The likely reason for the relatively large number of women not attending the post-natal visit at our hospital is the availability of post-natal services in public health care centres near their homes, and therefore women may have preferred those for convenience. However, we compared participants and non-respondents using medical hospital records and they did not differ according to several factors: age (P = 0.205), marital status (P = 0.480), smoking habits (P = 0.183), prenatal health care (P = 0.436), and number of prenatal health care visits (P = 0.214). Therefore, this limitation is unlikely to have affected our results significantly.
In Brazil, Quadrivalent and Bivalent HPV vaccines have been approved by regulatory authorities for females aged, respectively, 9 to 26 years and 10 to 25 years but they are not yet included in public vaccination programs [23, 24]. Despite the implementation of a national cervical cancer screening program based on cytology in Brazil, about 20,000 cervical cancer cases occur each year , indicating a need for revised efforts in education, prevention, and detection.
Although the possibility of knowledge of HPV can be changing in Brazil, probably it has not been changing significantly, because no large educational campaign about HPV for the population has been improved by the government in the last years.
Our findings could add information to knowledge of the Latin American scenario reflecting the views of young women of lower socio-economic status after first delivery. Despite the possibility to provide a large number of information to mothers during the prenatal and postpartum periods, this group of women had low levels of knowledge of HPV and cervical cancer development and prevention. Thus, these women could benefit greatly from educational interventions to encourage participation in primary and secondary cervical cancer prevention programs.