Comprehensive monitoring and management are required for women with chronic HBV infection during pregnancy, prenatally, and postpartum. Detection and quantification of cccDNA in liver tissue are considered the gold standard for reflecting HBV replication [19]. However, due to its invasive nature, this approach carries risks of bleeding and infection, which are particularly elevated in pregnant women [20]. Moreover, the lack of standardized methods for cccDNA measurement and technical barriers limit its application [21]. An increasing number of studies have reported the promising clinical value of serum pgRNA in monitoring CHB, treatment response, and prognosis [11, 12, 22]. However, more evidence-based medical data are needed, especially in the population of pregnant women with HBV infection. In our previous research, we first identified independent factors influencing pgRNA levels in pregnancy and postpartum groups, and preliminarily explored the potential association between pgRNA and MCTC blocking [23]. In this study focusing on CHB women from Southeast China, we described the clinical characteristics of pgRNA in pregnant, postpartum, and non-pregnant women under different treatment strategies and explored their relationships with traditional virological markers, aiming to provide a theoretical basis for the follow-up and treatment of pregnant women with HBV infection.
Previous studies have primarily focused on the changes in pgRNA among pregnant women with CHB at different clinical stages and the relationship between pgRNA and HBsAg reduction [17, 18]. This study uniquely introduced non-pregnant women of childbearing age for comparison. Among the 479 HBV-infected women analyzed, we examined the clinical characteristics of pgRNA during pregnancy, postpartum, and non-pregnant periods, as well as its correlations with traditional virological markers (HBV DNA, HBsAg, and HBeAg). We observed significant differences in clinical indicators such as DNA, ALT, AST, and pgRNA across the three stages of CHB women. A cohort study of HBsAg-positive pregnant women showed that the detectability rates of HBV DNA increased to 19.6% and 30.4% in the second and third trimesters, respectively, among those with initially undetectable HBV DNA-directly confirming the dynamic rise in viral load during pregnancy [24]. This phenomenon is closely associated with the pregnancy-specific immune-hormonal regulatory network: to maintain fetal tolerance, the maternal immune system develops a tolerance microenvironment characterized by Th2-type immune deviation and regulatory T cell proliferation, weakening HBV immune surveillance and promoting viral replication. Concurrently, pregnancy-related hormones (e.g., estrogen, progesterone, cortisol) directly enhance viral transcription and replication by activating HBV genomic regulatory elements (e.g., glucocorticoid response element GRE), contributing to elevated viral loads. On the other hand, the proportions of treated patients were higher in the postpartum (64/83) and non-pregnant (97/127) groups, whereas the pregnant group had a lower treatment rate (71/235). Since antiviral therapy reduces HBV DNA levels, this intergroup disparity in treatment proportions may influence comparisons of viral loads. Patients with positive pgRNA during pregnancy and postpartum tended to have higher levels of DNA, HBeAg, HBsAg, and ALT. Although the gestational immune tolerance state may temporarily suppress hepatic inflammatory responses, some pregnant women still develop mild liver injury due to high viral loads, manifested as mildly elevated ALT. In the postpartum period, with the resolution of maternal immune suppression, the immune system’s targeted clearance of HBV-infected hepatocytes can trigger fluctuating ALT elevation, which is notably associated with the rapid decline in HBV DNA load. Pregnant and postpartum patients with positive pgRNA reflect the interaction between viral replication and immune response, thereby influencing ALT levels. However, in non-pregnant women, only virological markers showed differences between pgRNA-positive and -negative groups, with no statistical differences in hepatic markers. This part of the study, covering women with chronic HBV infection at different disease stages, provides valuable insights into the role of pgRNA in pregnant women with chronic hepatitis B.
We also observed significant differences in the detection rates of pgRNA, DNA, and HBeAg across the three stages and under different treatment regimens in CHB women. The detection rate of HBV DNA fluctuated the most among the three groups, with the highest rate during pregnancy and the lowest in non-pregnant women. The detection rates of pgRNA and HBV DNA were highest in pregnant women receiving NUCs therapy, likely because pregnant women with high DNA levels or HBeAg positivity are recommended for antiviral treatment to prevent MTCT of HBV. Even when HBV DNA levels were below the detection limit, 41–47% of patients still tested positive for pgRNA. NUC therapy blocks the reverse transcription process, leading to intracellular accumulation of pgRNA rather than enhanced cccDNA transcriptional activity. In contrast, IFN directly suppresses cccDNA transcriptional activity and selectively eliminates cccDNA-containing infected hepatocytes by enhancing the activity of HBV-specific T cells and NK cells, directly reducing the cellular source of pgRNA. These findings highlight the critical mechanistic differences between NUCs and IFN: while NUCs inhibit viral replication but allow ongoing transcription, IFN targets cccDNA persistence and RNA stability directly. This provides a theoretical basis for exploring combination therapies (NUC + IFN), which may improve functional cure rates by simultaneously inhibiting viral replication and eliminating cccDNA. In HBeAg-negative patients, pgRNA was more readily detectable, whereas the opposite was true in HBeAg-positive patients. These findings suggest that optimal surrogate biomarkers need to be established at different stages of CHB women to accurately reflect intrahepatic viral activity. In non-pregnant women, the low detection rate of HBV DNA should not overshadow other potential virological markers. During pregnancy, in addition to monitoring HBV DNA and pgRNA, clinical symptoms and other test results should be integrated to assess the condition. Postpartum, changes in virological markers need to be closely monitored as the body’s physiological state recovers.
Through analyzing the overall correlation of virological markers in 479 HBV-infected women, we found that pgRNA was highly associated with HBeAg in female CHB patients regardless of pregnancy status (pregnant, postpartum, or non-pregnant). However, the correlation between pgRNA and HBeAg appears to be weaker in both the pregnant and postpartum groups compared to the non-pregnant group. Specifically, antiviral therapy in pregnant patients was initiated at 24 weeks of gestation and continued until 3 months postpartum, resulting in a shorter treatment duration of approximately 6–9 months for both pregnant and postpartum groups. In contrast, non-pregnant women of childbearing age in our research typically received antiviral therapy for over 2 years, with a significantly longer treatment duration. Studies have reported that pgRNA levels gradually decrease after 1, 3, and 5 years of NUC treatment, indicating that the time of antiviral therapy affects pgRNA levels [25]. The weakened correlation between HBeAg and pgRNA during pregnancy and postpartum may be attributed to different treatment durations. Consistent with previous studies, a moderate correlation was observed between pgRNA and HBV DNA levels [26, 27], which was more pronounced in untreated patients. Once NUCs treatment is initiated, the reverse transcription process ceases, and the synthesis of DNA from RNA is halted, leading to a rapid decline in DNA levels [28]. However, the levels of circulating HBV RNA transcribed directly from cccDNA remain relatively stable, resulting in a reduced correlation between pgRNA and DNA after treatment. Interestingly, the correlation between serum pgRNA and HBsAg was consistently the weakest. This difference supports the emerging view that circulating HBsAg may originate from HBV DNA fragments integrated into the human genome, rather than from cccDNA. Serum HBsAg can also be derived from the expression of integrated HBV S gene in patients with S gene integration [29, 30]. Therefore, serum pgRNA may be more stable than serum HBsAg in reflecting intrahepatic cccDNA.
Finally, through dynamic monitoring of virological markers (HBV DNA, pgRNA, and HBsAg) in CHB pregnant women at different stages, we revealed the patterns of viral activity during pregnancy and postpartum. From mid-pregnancy to late pregnancy, HBV DNA and pgRNA levels significantly decreased, while HBsAg levels remained stable. Longitudinal observation revealed that pgRNA levels decline with continuous NUC treatment, likely due to gradual depletion of the cccDNA pool, cumulative epigenetic modifications, and turnover of infected hepatocytes, ultimately leading to reduced pgRNA levels. This trend was not observed in the 10 untreated patients, indicating that NUCs treatment effectively suppresses viral replication during pregnancy and further supports the necessity of antiviral therapy during this period. From late pregnancy to 0–3 months postpartum, HBsAg and HBV DNA levels significantly increased, while pgRNA levels remained relatively stable. This phenomenon may be related to the recovery of the immune system postpartum. After childbirth, the maternal immune system gradually returns to normal, potentially leading to a rebound in viral replication. From 0 to 3 months postpartum to 4–12 months postpartum, no statistically significant changes were observed in virological markers. This suggests that the first three months postpartum is a critical period for viral activity changes, after which viral activity stabilizes. This finding indicates that the first three months postpartum is a key period for viral activity changes, and treatment strategies targeting this unique immune adjustment period may more effectively control viral activity and improve long-term patient outcomes.
In addition to tracking viral activity in pregnant and postpartum patients, we also focused on pgRNA changes in women of childbearing age under different treatment regimens. Previous studies have reported that under NUCs treatment, pgRNA levels decrease minimally, with only 16.3% of patients undetectable for pgRNA after five years of first-line NUCs therapy [25]. In contrast, during IFN treatment, HBV pgRNA levels significantly decline, and patients with HBeAg seroconversion have lower pgRNA levels [31, 32]. These findings are consistent with our study, in which pgRNA levels showed no significant differences in eight non-pregnant women treated with NUCs, revealing the limited impact of NUCs on the upstream transcription of viral replication. In contrast, pgRNA levels significantly decreased in 12 non-pregnant women treated with IFN, indicating that IFN treatment effectively suppresses viral replication and reduces viral load. Further studies have reported that the combination of HBV RNA and HBsAg can identify patients who are more likely to achieve sustained virological response to interferon therapy [33]. The above results demonstrate the multifaceted importance of pgRNA in the diagnosis and treatment of hepatitis B. However, the relatively small sample size in this study limits the generalizability of the findings. Future studies should expand the sample size of HBV-infected patients to further validate these discoveries.
To our knowledge, this is the first study to comprehensively describe the characteristics of pgRNA in pregnant, postpartum, and non-pregnant women with chronic HBV infection and to track pgRNA changes in 90 patients across different stages and under different treatment regimens. However, our study has some limitations. Based on real-world clinical retrospective practice, our study inevitably suffers from retrospective bias. First, the sample size of postpartum patients was relatively small. Second, we only followed up with patients twice, making it difficult to assess the long-term effects of treatment and potential long-term risks. Therefore, future studies should expand the sample size and increase the frequency of long-term follow-up to obtain more comprehensive and accurate data, thereby providing a more reliable basis for the treatment and management of chronic HBV infection during pregnancy and postpartum.