Both mother and child are now said to be stable but are in hospital in Palmas.
A London-bound flight with more 100 passengers had to make an emergency landing in Palmas, Spain, on Sunday when a woman gave birth mid-air.
The woman, whose identity has been withheld, is reported to have experienced excessive hemorrhaging during labour. The pilot of the Nigerian Arik Air aircraft is believed to have requested the emergency landing on the advice of two doctors on board.
According to Nigerian newspaper This Day, the airline is now investigating to ascertain whether the woman had presented a false medical report from her doctor on the true length of her pregnancy or whether she had gone into premature labour while on board.
Women who are over 32 weeks pregnant are not allowed to travel by air, according to International Civil Aviation Organisation (ICAO) regulations. All pregnant passengers are required to present medical reports certifying that they are less than 32 weeks pregnant before they are allowed to fly.
Arik Air's management told This Day that if the woman was given a false report to enable her fly, it would file a complaint against the doctor who had issued the medical report to the Nigeria Medical Association (NMA) for endangering her life and that of the baby, as well that of other passengers on board the flight.
There has been a spate of women giving birth mid-air recently. Last month, a woman gave birth to a baby boy on a Royal Air Maroc flight between Casablanca and the Italian city of Bologna, causing the flight to be diverted to Barcelona.
In July a woman went into labour on a Saudi Airlines flight from Jeddah, and earlier this year, a passenger gave birth aboard a plane flying to Armenia from Siberia.
Woman gives birth on flight from Milan to Paris