This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Highest transmission of hepatitis B from mother to fetus occurs if the mother is infected during: \nSelect and explain. \nA. Ist trimester, B. IInd trimester, C. IIIrd trimester, D. At the time of implantation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Viral hepatitis is the commonest cause of jaundice in pregnancy in the tropics.\nHepatitis A (HAV):\n\nInfection is spread by faecal-oral route.\nDiagnosis is confirmed by detection of IgM antibody to hepatitis A (anti HAV Igm).\nDisease is usually self limited and fulminant hepatitis is rare.\nPerinatal transmission is rare, chronic carrier state does not exist.\nThe virus is not teratogenic.\nPregnant woman exposed to HAV infection should receive immunoglobulin 0.02 ml/kg within 2 weeks of exposure. She should also have hepatitis A vaccine single dose 0.06 ml IM. It is safe in pregnancy.\n\nHepatitis B virus (HBV):\n\nThe virus is transmitted by parenteral route, sexual contact, vertical transmission and also through breast milk.\nThe risk of transmission to fetus ranges from 10% in first trimester to as high as 90% in third trimester and it is specially high (90%) from those mothers who are seropositive to hepatitis B surface antigen (HBsAg) and ‘e’-antigen (HBeAg).\nNeonatal transmission mainly occurs at or around the time of birth through mixing of maternal blood and genital secretions. Approximately 25% of the carrier neonate will die from cirrhosis or hepatic carcinoma, between late childhood to early adulthood.\nHBV is not teratogenic.', 'role': 'assistant'}]