Most of the women received treatment on the NHS as they were to close to giving birth to return home.
The total exploiting the health service is thought to much higher, as Gatwick has a limited number of flights from countries with the highest rate of so called health tourists.
Despite airlines usually not allowing mothers-to-be who are more than 36 weeks pregnant to fly, the women were able to gain entrance to the UK by uses forged doctors notes which hid how far along they were.
The revelation comes from a previously unpublished report seen by the Sunday Telegraph which was prepared in 2010 on plans to refuse those from abroad with unpaid NHS.
Another report included quotes from an immigration officer who was furious at the extent of the problem.
He said: "Sometimes they will come back for their second or third baby.
"Sometimes they will quite blatantly say, 'I'm coming because the care is better', and once they are here, if they are assessed to a certain gestation, then we are stuck."
Health tourism costs the NHS up to £80 million a year - enough to pay for around 2,000 nurses - the Government has said.