If a woman really wants to get around the rules barring her from flying in late pregnancy, there's little an airline can do to stop her.
Investigators believe that a Filipino maid who gave birth in an airplane toilet two weeks ago deliberately wore baggy clothes and some sort of girdle around her stomach to conceal her pregnancy, Gulf Air spokeswoman Katherine Kaczynska said Tuesday.
It's not clear how far along the Filipino woman was in her pregnancy when she boarded the 10-hour Gulf Air flight from Bahrain to Manila, the spokeswoman said.
The airline has procedures to identify pregnant women checking in for flights, "but if someone conceals the pregnancy, it's difficult and nigh on impossible for us to tell," Kaczynska said.
While the vast majority of women heed airline rules against flying during the last four or five weeks of pregnancy or comply with requirements about providing a medical certificate from a doctor, some manage to conceal their condition or lie about how far along they are so they can get where they want to go.
United Airlines flight attendant Sara Nelson says she raised eyebrows last year when she flew while eight months pregnant. She was legal but looked ready to give birth at any moment.
"I got reactions everywhere, because I really think it is quite rare that you see people flying so advanced in their pregnancy," said Nelson, who is also the spokeswoman for the United Airlines branch of the Association of Flight Attendants-CWA. "I probably scared people a little bit."
Few babies born on planes
In-flight births are so infrequent they aren't tracked by airline associations. Much more common are passenger medical emergencies like heart attacks and anxiety attacks, or travelers who pass out after taking tranquilizers or drinking alcohol.
The Filipino woman says she had been raped and impregnated by her employer in Qatar, then forced by her employer's wife to return home. She managed to hide the pregnancy to board the plane, then went into labor, giving birth in the packed jet's toilet without any other passengers or the flight crew noticing.
She abandoned her six-pound, nine-ounce baby boy in the trash, saying she feared what her family would say. The child is doing fine under the care of authorities and the woman could face child abandonment charges.
A Samoan woman on a flight to New Zealand gave birth the same way last year — again without anyone noticing. That child was also saved from the trash and survived, and the woman was convicted of abandonment and deported.
Since 2007, babies have also been born aboard planes flying from Chicago to Salt Lake City; on a domestic flight in Malaysia; and on long-haul flights from the Netherlands to Boston, from Hong Kong to Australia, and from Germany to Atlanta.
But even when gate attendants question how pregnant a passenger is, they usually have no choice but to let the woman fly if she says she has not reached the airline's cutoff date and is showing no sign of physical distress, said Dr. Fanancy Anzalone, president-elect of the Aerospace Medical Association in Alexandria, Va.
"The rules now are based on honesty and (the idea) that a pregnant mom is going to protect her unborn," Anzalone said.
If gate attendants believe a pregnant woman is farther along than allowed or showing possible signs of labor or distress, they can call medical personnel to determine whether she has the necessary medical documentation and is fit to fly, Anzalone said.
Randy Petersen, the editor for the U.S.-based Inside Flier magazine, said busy gate attendants face a diplomatic nightmare when asking about pregnancies because all women show the condition differently and heavy women can look pregnant when they are not.
"The person could be overweight. That is a faux pas that could happen that could lead to uncomfortable situations," Peterson said. "It is an honor system, and if a lady is willing to take a risk — and a lot of things can go wrong — that's their liability, not an airline liability."
Putting new airline rules in place would be difficult, experts say.
"Ultimately, you are legislating the unlegislatable. If a passenger doesn't tell you their condition, you have no way of knowing," said David Henderson, spokesman for the European Association of Airlines.
Medical experts say the main reason very pregnant women should not fly is because there is no guarantee of adequate medical care on a plane.
Doctor, nurses or other health care professionals are frequently aboard as passengers and flight attendants with onboard medical kits can use satellite phones to call for help. But international flights can be hours from an airport and no flights have the sophisticated medical equipment needed for labor emergencies.
"(An airplane) is not a very clean environment and it's just not the place to deliver a child," said Jeffrey Sventek, the Aerospace Medical Association's executive director.
Flight crews always note where pregnant women are sitting and tell the rest of the crew, said Capt. Tom Walsh, a pilot who flies international routes.
"They will keep an eye on them, they will let us know and usually it's not a problem," he said. "But it's so easy to hide the fact you are pregnant."
It's also a mystery how no one noticed anything amiss when the Filipino woman was giving birth in the bathroom. Flight attendants and passengers who were questioned all said they saw nothing amiss, said Kaczynska of Gulf Air.