GENEVA (AP) _ Mother Teresa, who won the 1979 Nobel Peace Prize for her work on behalf of the Third World's sick and poor, is to travel to Baghdad at the invitation of Saddam Hussein's government, a U.N. official said Friday.

The U.N.'s relief coordinator for the Persian Gulf, Sadruddin Aga Khan, described Mother Teresa's visit to Iraq next week as ''good news,'' but said he had no details of her itinerary. He said she was invited by the Iraqi Health Ministry.

Sadruddin initially said Mother Teresa would travel Monday to Baghdad aboard a special U.N. flight from Geneva. But a U.N. spokesman, Theo Loir, said later that plans had been changed and Mother Teresa would fly to Baghdad from Rome on a commercial airliner.

The change in travel arrangements prompted speculation that U.N. officials had second thoughts about getting the United Nations involved in what might be perceived as an effort by Saddam to improve his image abroad.