Saturday, September 28, 2013

Caesarians Reduce Infection When Mothers Have High Viral Loads

Caesarians Reduce Infection When Mothers Have High Viral Loads

A study published in the journal Clinical Gastroenterology and Hepatology finds that Caesarean deliveries reduce the risk of hepatitis B infection in babies born to mothers who have high viral loads of the hepatitis B virus (HBV). Currently, immediate immunization and treatment with hepatitis B antibodies (HBIG) at birth prevents mother-to-child infection in more than 90% of cases. However, about 6% to 7% of infants born to mothers with high viral loads (more than 1 million copies/mL) become infected despite preventive measures.

While doctors are starting to treat pregnant women with high viral loads with antivirals during the last trimester of pregnancy to reduce viral load, this treatment is new and does not have U.S. Food and Drug Administration approval yet and some women experience a sudden surge in their HBV DNA during the last few months or weeks of pregnancy, precluding effective use of antivirals.

A global group of researchers studied 1,409 infants and found that babies born to highly-infectious mothers had lower rates of infection when they were delivered by elective Caesarean (2.9%) as opposed to vaginally (6.3%) or by emergency Caesarean (7.6%).

Source: http://www.cghjournal.org/article/S1542-3565%2813%2900586-7/abstract

Abstract: Cesarean Section Reduces Perinatal Transmission of Hepatitis B Virus Infection From Hepatitis B Surface Antigen–Positive Women to Their Infants

Calvin Q. Pan, Huai-Bin Zou , Yu Chen, Xiaohui Zhang, Hua Zhang, Jie Li, Zhongpng Duan

Background & Aims
Despite appropriate passive and active immunization, perinatal transmission of hepatitis B virus (HBV) still occurs in 5%–10% of infants born to women with high levels of viremia who test positive for the hepatitis B e antigen (HBeAg). We evaluated the effects of cesarean section delivery on perinatal transmission of HBV from women who tested positive for the hepatitis B surface antigen (HBsAg).

Methods
We analyzed data from 1409 infants born to HBsAg-positive mothers through vaginal delivery (VD) (n = 673), elective caesarean section (ECS) (n = 496), or urgent cesarean section (UCS) (n = 240) who completed appropriate immunization against HBV. The prevention was assumed to have failed for infants who were HBsAg positive when they were 7–12 months old; this information was used to assess transmission rates.

Results
HBV infection was transmitted to a smaller percentage of infants born by ECS (1.4%) than by VD (3.4%, P < .032) or UCS (4.2%, P < .020). UCS had no effect on vertical transmission, compared with VD (4.2% vs 3.4%, P = .593). Infants born by ECS had a significantly lower rate of vertical transmission than those born by non-ECS (1.4% vs 3.6%, P = .017). Women with HBV DNA levels <1,000,000 copies/mL did not transmit the infection to their infants, regardless of method of delivery. There were no differences in maternal or infant morbidity and mortality among the groups.

Conclusions
There is a significantly lower rate of vertical transmission of HBV infection to infants delivered by ECS, compared with those delivered vaginally or by UCS. Elective cesarean sections for HBeAg-positive mothers with pre-delivery levels of HBV DNA ≥1,000,000 copies/mL could reduce vertical transmission.

Pan CQ. Clin Gastroenterol Hepatol. 2013;11:1349-1355.

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