Six-week-old suffered cardiac arrest during ceremony, which involves three immersions in holy water

A Romanian Orthodox priest sinking a child in holy water during baptism, in a church in BucharestOrthodox priests immerse a child in holy water three times during baptism. Photograph: Daniel Mihăilescu/AFP/Getty Images

The Orthodox Church in Romania is facing growing pressure to change baptism rituals after a baby died following a ceremony which involves immersing infants three times in holy water.

The six-week-old suffered a cardiac arrest and was rushed to hospital on Monday but he died a few hours later, the autopsy revealing liquid in his lungs. Prosecutors have opened a manslaughter investigation against the priest in the north-eastern city of Suceava.

An online petition calling for changes to the ritual had gathered more than 56,000 signatures by Thursday evening. “The death of a newborn baby because of this practice is a huge tragedy,” said a message with the petition. “This risk must be ruled out for the joy of baptism to triumph.”

One internet user denounced the “brutality” of the ritual and another criticised the “stubbornness of those who think that it is the will of God” to maintain it.

Local media recounted several similar incidents in recent years. Church spokesman Vasile Banescu said priests could pour a little water on the baby’s forehead instead of full immersion. But Archbishop Teodosie, leader of the Church’s traditionalist wing, said the ritual would not change.

More than 80% of Romanians are Orthodox and the Church is one of the most trusted institutions, according to recent opinion polls.