The mean age of the 1873 parturient women included was 27.84 ± 6.78 years. Their marital profile revealed that 83.13% were single (n = 1557) and 16.87% were married (n = 316). The distribution of women by occupation revealed that 75.97% were unemployed (n = 1423), 13.03% were civil servants (n = 244), and 11% were traders (n = 206). In terms of education, 76.94% had a secondary education (n = 1441), 20.72% had a primary education (n = 388), and 2.35% had a higher education (n = 44).

Among the 1873 parturients, there were 1386 multiple pregnancies (74%), 463 multiparous (24.7%), 486 pauciparous (26%), and 924 primiparous (49.3%). The mean number of antenatal consultations (ANC) was 3.32 ± 1.5. There were 1830 (97.7%) women who had more than 4 prenatal visits. Regarding gestational age, 1667 (89%) women gave birth at a gestational age greater than or equal to 37 weeks, while 206 (11%) gave birth before 37 weeks (Table 1).

Table 1. Reproductive characteristics of women who had more than 4 prenatal visits.

Among the 1873 parturients, 1810 (96.6%) were tested for HIV, and among these, 49 were positive, corresponding to a frequency of 2.71%. Hepatitis B was tested in 1565 parturients (83.56%), and 57 were positive, corresponding to a frequency of 3.64%. Hepatitis C was tested in 1181 (63%) with 2 parturients positive, corresponding to a frequency of 0.17%. There were no viral co-infections among the women tested. Risk factors for hepatitis B infection. The main factors that appeared to be associated with a positive maternal hepatitis B test were the presence of a tattoo (OR 0.4 [0.15 - 0.87]; p 0.026), the presence of scarification (OR 3.47 [1.7 - 6.47]; p 0.000), and the level of overcrowding with at least 5 people living in the household (OR 2 [1.12 - 3.89]; p 0.019) (Table 2).

Table 2. Risk factors for HBV.

Prevention of mother-to-child transmission. Among the 57 HBsAg-positive women, two were followed by a gastroenterologist, representing a rate of 3.51%. None were on antiviral treatment. Of the 1873 newborns, 40 received the birth dose of the HBV vaccine, representing 2.14%. Among the 57 babies born to mothers who tested positive for hepatitis B, 40 had been vaccinated against hepatitis B at birth (70.18%), and 36 had simultaneously received hepatitis B serum (63.16%) (Table 3). No child born to a seronegative mother received the hepatitis B vaccine at birth.

Table 3. Means of HBV prevention in newborns born to women.

The profile of the parturients was that of a young woman (27.84 ± 6.78 years), single (83.13%), unemployed (75.97%) with a secondary level of education (76.94%). This profile is similar to the data from the 2019-2021 Demographic and Health Survey (DHS) [7]. This profile is also found in some African studies [8]-[10]. In terms of obstetrics, 49.3% were primiparous and 25.95% were pauciparous. This confirms the data from the 2019-2021 DHS, in which the average age of first pregnancy was 20.4 years, and 83% of pregnancies occurred between 20 and 30 years old [7]. The quality of pregnancy follow-up, assessed by the number of prenatal consultations, revealed that 97.7% had benefited from more than 4 prenatal consultations as recommended by the WHO [11]. This threshold of 4 prenatal consultations is associated with a good obstetric prognosis [12]-[16].

The prevalence of HBsAg among admitted parturients in the delivery room of the CHU of Libreville, was 3.6%. This prevalence was similar to that reported by Koumba et al. among pregnant women in the south of the country (Franceville), which was estimated at 3.9% [17]. It is also close to studies conducted among pregnant women in Rwanda and Tanzania, with HBsAg prevalence of 3.1% and 3%, respectively [18][19]. This prevalence was lower than previous studies carried out in Gabon by Misso et al., which reported a seroprevalence of 8.3% at the Melen Estuaire Regional Hospital in 2022 [20]. This difference could be related to variations in prevalence within the country as revealed by the DHS 2019-2021 [7]. In addition, Ndeboko et al. observed a decrease in the prevalence of hepatitis B among pregnant women since the COVID-19 epidemic at the Libreville Mother and Child University Hospital [21]. This prevalence of hepatitis B was lower than that observed among pregnant women in some sub-Saharan African countries, such as Benin, Cameroon, and Congo, where Alassan et al., Mawouma et al., and Ngalula et al. reported rates of 14.02%, 18.4%, and 6.9%, respectively [22]-[24]. These variations are consistent with the epidemiological data on hepatitis B, classifying Gabon as a zone of intermediate prevalence [25][26].

Among the known risk factors for hepatitis B transmission, only the presence of scarifications and close living conditions were associated with an increased risk, by 3.47 and 2 times, respectively [27]. The notion of tattooing was associated with a 0.4-fold decrease in the risk of contracting hepatitis B. This was an unexpected finding contrary to some literature. Indeed, this observation is contrary to that of Nkoh in Cameroon [28]. This difference could be explained by a higher level of professionalism in the tattoo industry in Libreville but is a hypothesis requiring further investigation. A history of blood transfusion was not associated with the risk of hepatitis B. This result could be explained by increased transfusion safety measures, including strict donor selection and biological qualification of blood donations through appropriate virological tests at the national transfusion center [29][30].

Among the 57 HBsAg-positive pregnant women, only 2 were monitored by a gastroenterologist (3.51%) and none were receiving treatment. This confirms WHO data, which indicate that more than 50% of people with viral hepatitis are unaware of their infection and over 80% of people do not have access to treatment [1][2]. No child born to mothers who were hepatitis B seronegative or of unknown serological status received the hepatitis B vaccine. This is due to the fact that the monovalent hepatitis B vaccine is not available in the delivery room. Patients must pay for it themselves, and this cost is not reimbursed by national health insurance. This reality also explains why 70.18% of children born to mothers carrying hepatitis B were able to be vaccinated, and 63.16% of these children had received hepatitis B antiviral immunoglobulins. The absence of a national viral hepatitis control program could explain these shortcomings [31]. Although this data is limited to a single healthcare facility, the Libreville University Hospital is the largest healthcare facility in the country, and this data reflects the realities of all healthcare facilities in Gabon.