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Hepatitis B virus infection characterized by HBsAg positivity during pregnancy is a well-recognized issue in developing countries, but the association between HBsAg positivity and adverse maternal outcomes remains uncertain. To examine the association between HBsAg positivity during pregnancy and adverse maternal outcomes, a retrospective cohort study was conducted in Sichuan province, China. Deliveries were recorded from six hospitals between 1 January 2009 and 31 December 2010. Pre-eclampsia, gestational diabetes mellitus ( GDM), postpartum haemorrhage ( PPH), intrahepatic cholestasis, Caesarean section and placenta previa were prespecified adverse maternal outcomes. We used two multivariate logistic regression models to assess the association between HBsAg positivity and adverse maternal outcomes. In total, 948 (4.2%) pregnant women were HBsAg positive from 22 374 deliveries. Pregnant women with positive HBsAg had higher risk of GDM ( aOR1.41, 95% CI 1.15-1.74), PPH (1.44, 1.13-1.83), intrahepatic cholestasis (1.74, 1.40-2.16) and Caesarean section (1.24, 1.06-1.45). No statistical associations were found between HBsAg positivity and pre-eclampsia (1.36, 0.94-1.97), and placenta previa (1.21, 0.87-1.67). HBsAg positivity during pregnancy was associated with higher risk of multiple adverse maternal outcomes. Although the causality has yet to be established, efforts may be warranted in routine care, particularly in those with high risk for adverse maternal outcomes, given the volume population infected with HBsAg. Future studies are needed to establish causality and examine the impact of HBeAg on the adverse outcomes. [ABSTRACT FROM AUTHOR]

On 12 May 2008, the MW 7.9 Wenchuan earthquake ruptured two northeast-striking imbricated reverse faults and one northwest-striking reverse fault along the middle Longmen Shan thrust belt, at the eastern margin of the Tibetan plateau. The morphology of the coseismic scarp varies drastically along strike. We distinguish eight different categories: (1) simple thrust scarp, (2) hanging-wall collapse scarp, (3) simple pressure ridge, (4) dextral pressure ridge, (5) fault-related fold scarp, (6) backthrust pressure ridge, (7) local normal fault scarp, and (8) pavement suprathrust scarp. The coseismic surface ruptures confirm that the Wenchuan earthquake is dominated by reverse faulting with some right-lateral component that varies from site to site. The surface rupture can be divided into two parts, the Yingxiu segment and the Beichuan segment. When the earthquake is split into two subevents accordingly, they correspond to an MW 7.8 event and an MW 7.6 event, respectively. These two segments can in turn be divided into four second-order subsegments, which are equivalent to four subevents of MW 7.5, MW 7.7, MW 7.0, and MW 7.5, respectively. The segmentation of the rupture is consistent with a cascading-rupture pattern, responsible for the total 110 s of the earthquake rupture. In addition to surface ruptures, the focal mechanisms determined for the aftershocks recorded by the local seismic network are used to constrain the fault geometry of the subsegments. They show that the dip of the fault responsible for the earthquake varies along strike, and the fault tends to flatten at depth. In addition, the fault plane gets steeper northward, enabling the fault to accommodate a larger strike-slip component along a lateral ramp. This major earthquake confirms that crustal shortening could be the main driving force for the growth of high topography along the eastern margin of the Tibetan Plateau and that lower crustal flow is not required. [ABSTRACT FROM AUTHOR]