MANILA, May 11 (Reuters) - The Philippine economy shrank by more than expected in the first quarter of 2021, official data showed on Tuesday, as prolonged pandemic-induced lockdowns kept domestic demand sluggish. The gross domestic product fell 4.2% in the March quarter from a year earlier, the statistics agency said. Economists in a Reuters poll had expected the economy to contract 3.0% after falling 8.3% year-on-year in the previous quarter. (Reporting by Neil Jerome Morales, Karen Lema and Enrico Dela Cruz; Editing by Himani Sarkar) Our Standards: The Thomson Reuters Trust Principles.