Hepatitis B virus (HBV) infection is a global public health problem, and China is the country with the largest burden of hepatitis B virus (HBV) infection. At present, there are about 70 million people infected with HBV in China, and mother-to-child transmission is an important way to cause the spread of hepatitis B virus in China.
A nationwide cross-sectional study of pregnant women in China, "HBV Infection in 90 Million Pregnant Women in 2853 Counties in China 2015-2020," published in The Lancet - Regional Health (Western Pacific), assessed the prevalence of hepatitis B virus infection. The results show that from 2015 to 2020, HBV infection in pregnant women in China was moderately prevalent, and the prevalence rate continued to decline, decreasing by about 25%. However, there are still differences in the prevalence of HBV infection at the provincial and county levels. Provinces with a relatively heavy burden of HBV infection should pay more attention in the future.
Compared with 2015, the prevalence of HBV infection among pregnant women in the three regions of eastern, central and western China has decreased, from 8.72% to 6.04% in the eastern region, from 6.76% to 4.93% in the central region, and from 6.40% to 5.43% in the western region. Regional disparities have also narrowed between 2015 and 2020.
Between 2015 and 2020, the prevalence of HBV infection decreased in most provinces (90.3%) and districts (76.96%), but there are still differences.
Among them, in 2020, the prevalence of HBV in 31 provinces ranged from 1.88% to 11.99%.
In 2020, the prevalence rates in Tianjin (1.97%) and Shanxi (1.88%) were low (
However, the prevalence rate remains high in 6 provinces (≥8%), including: Hainan (11.99%), Tibet (11.25%), Jiangxi (10.56%), Fujian (9.97%), Guangdong (9.84%) and Guangxi (9.30%).
In the county-level areas, from 2015 to 2020, the proportion of areas with higher prevalence rates (≥8%) decreased from 24.26% to 17.54%.
Trends in the prevalence of hepatitis B virus in pregnant women nationwide from 2015 to 2020
Regional differences in HBV carrying among pregnant women in the whole population (black line), eastern (red line), central (yellow line) and western (blue line) in China from 2015 to 2020
Blocking mother-to-child transmission of HBV is the key to eliminating hepatitis B, and the standardized management of HBV-infected pregnant women and their newborns can effectively cut off mother-to-child transmission of HBV. Newborn hepatitis B immunoglobulin (HBIG) and hepatitis B vaccination for infants born to HBV-positive pregnant women are effective in reducing neonatal HBV infection.
Understanding the epidemiological characteristics of HBV infection among pregnant women in China and better regulating the prevention, diagnosis and treatment of this group are of great significance for achieving the WHO(WHO) goal of "eliminating viral hepatitis as a major public health threat by 2030".
Clinical diagnosis of HBV infection
Diagnostic criteria: HBsAg positive is diagnosis of HBV infection.
(1) Chronic HBV infection, that is, HBsAg positive for more than six months, normal liver function.
(2) Chronic hepatitis B, that is, HBsAg is positive, abnormal liver function and excludes other causes.
Mother-to-child transmission of HBV
Most current studies have identified HBsAg-positive and/or HBV DNA-positive infants at 6 or 7 months of age as criteria for the occurrence of mother-to-child transmission. A positive DNA of venous or cord blood HBsAg and/or HBV at birth does not indicate mother-to-child transmission. The timing of mother-to-child transmission usually occurs during and after childbirth, and intrauterine infections are very rare.
Effects of pregnancy with HBV infection on pregnant women
Pregnancy with HBV infection has an effect on metabolic abnormalities, liver damage, preterm birth, miscarriage, gestational diabetes mellitus (GDM), and hypertension during pregnancy.
Liver damage
Previous studies have shown that the probability of liver function impairment in pregnant women is as high as 3%, the incidence of acute attacks of hepatitis B in pregnant women is 6%, and the incidence of acute attacks of hepatitis B after childbirth is 10%.
premature birth
Infection with HBV in pregnant women increases the risk of preterm birth. A retrospective cohort study conducted by Liu et al. in 489965 women of childbearing age found that HBsAg-positive pregnant women had a 24% increased risk of preterm birth compared to HBsAg-negative pregnant women. Pregnant women who are double positive for HBsAg and HBeAg are at greater risk of preterm birth.
abortion
The cause of high miscarriage rates in pregnant women is that the integration and replication of HBV genes lead to chromosomal variation in early embryonic cells, and viral protein products interfere with the metabolism and development of embryos.
Gestational Diabetes Mellitus (GDM)
HBsAg-positive during pregnancy is associated with a higher risk of developing GDM in pregnant women, and the prevalence of GDM in HBsAg-positive pregnant women is significantly higher than that in HBsAg-negative pregnant women. The mechanism of influence of hepatitis B infection status on GDM may be that tumor necrosis factor causes insulin resistance in pregnancy.
Hypertension in pregnancy (PIH)
Multiple studies have shown that HBsAg-positive pregnant women have a higher risk of PICH than HBsAg-negative pregnant women.
Effects of pregnancy with HBV infection on perinatal infants
Studies on the effects of pregnancy complicated by HBV infection on perinatal infants have focused on low birth weight, macrosomia, gestational-age infants, and fetal distress.
Low birth weight
Multiple studies have shown that HBsAg-positive pregnant women have a higher risk of producing low birth weight infants than HBsAg-negative pregnant women, but the results are not significant, and the relationship between the two needs to be further studied.
Huge
Multiple studies have shown that HBsAg-positive pregnant women have a higher risk of delivering macrosomia than HBsAg-negative pregnant women, and HBsAg-positive pregnant women also have a higher risk of intrauterine death in fetuses. However, some studies have said that no association has been found between the two.
Small-for-gestational-age infants
Foreign studies have not determined the correlation between the two, and further research is needed.
Fetal distress
There is an association between fetal distress and mothers carrying HBsAg, and newborns born in HBsAg-positive pregnant women have a higher risk of fetal distress than HBsAg-negative pregnant women.
Immunoprophylaxis for mother-to-child transmission
Newborns delivered by HBsAg-positive mothers should receive passive-active immunization (HBIG and hepatitis B vaccines) within 12 hours of delivery, which is key to preventing mother-to-child transmission.
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Editor-in-Charge: Ma Ye