RIO DE JANEIRO — Ana Lobo, who is six months pregnant, was at a pre-Carnival street party last weekend when a man started yelling and calling her names. “Whore!” she remembered him saying, apparently because she was wearing a revealing top. “Some men have this feeling that they can do whatever to your body,” said Lobo, a 29-year-old artist who later that night attended one of the many feminist-themed parties.