A controversial birth control law came into effect in the Philippines Thursday after more than a decade of bitter opposition from the Catholic church, in an historic move welcomed by many women. The law requires government health centres to hand out free condoms and birth control pills, benefiting the country's poor who would not otherwise have access, and mandates that sex education be taught in schools. The government is still working on the measure's finer details, including how to allocate funding to different regions and at what age to introduce sex education, according to officials. Supporters say the measures will help moderate the nation's rapid population growth, reduce poverty and bring down high maternal mortality. But Catholic groups have already shifted their battle to the courts, questioning the law's constitutionality. The church, which counts 80 percent of Filipinos as followers, forbids the use of artificial contraceptives. The government also has to go through "consultations" with various stakeholders including international and local medical and religious groups, said Hazel Chua, an official at the Health Department's family planning unit. "It has a lot of broadstrokes in it that need a lot of guidelines. It will take a lot of time before (the law) will go down to the ground," she told AFP. Under the law, government health centres will be guaranteed a supply of contraceptives, unlike in the past when local mayors could be intimidated by the church into not providing birth control services, Chua said. One provision of the law, legalising post-abortion medical care, is still undergoing special study since abortion remains illegal in the Philippines, Chua added. "The abortionist is criminally liable and should be prosecuted (but)... if someone comes in after (an abortion) and is haemorrhaging, we have to take good care of them," she reasoned. The medical charity Merlin praised the law as a "milestone" but said more efforts were needed to make sure it was properly implemented. "There is likely to be cultural opposition... led by religious conservatives, which could make it hard for clinics to offer services," said country director Maxime Piasecki. President Benigno Aquino signed the bill into law last month in the face of strong lobbying by the Catholic church, and religious leaders have vowed that the fight was not over. The church is now relying on lay groups that have filed petitions with the Supreme Court to challenge the law, said Roy Lagarde, a spokesman for the country's Catholic bishops. But the legislation's chief author Congressman Edcel Lagman said he was confident it would not be struck down. "We have long expected that the opposition will go to the Supreme Court. We have prepared for this eventuality," he told AFP. Housewife Nerissa Gallo, 44, who has given birth to 16 children, said she welcomed the law which would bring contraceptives into the reach of the poor. Asked about the church's opposition, she said: "We don't pay attention to that. They are not the ones who are giving birth again and again. We are the ones who have to find a way to care for the children."