Krithika, who gave birth to her second child, died of excessive bleeding after the delivery assisted by her husband, his friend and the latter's wife -- none of whom were medically qualified - at their home, they said.
The woman fell unconscious and both the mother and her newborn were rushed to a government hospital in Tirupur, where the doctors declared her dead on arrival on Sunday.
The baby has been hospitalised, police said.
The locals informed the Child Development officials who filed a complaint with police.
Karthikeyan, the woman's husband, was detained and police are questioning him.
According to preliminary investigations, Karthikeyan, employed at a knitwear company, and Krithika, had a five-year old child. After she conceived for the second time, the couple started following instructions from social media such as Facebook and Youtube.
On July 22, when Krithika went into labour, her husband called his friend Praveen and his wife for help to have a normal delivery at home.
They set in motion the process for normal delivery by watching instructions through mobile phone and computer and Krithika gave birth to the girl.
However, she fell unconscious due to excessive bleeding and died.