For every woman, the risk is always there after a baby comes. It's known as the third stage of labour, when the placenta peels away from the uterine wall to wend its way down the birth canal. It leaves behind a wound "the size of a small pizza," a tear about 20 centimetres across.
If all goes well, the uterus naturally contracts to close around blood vessels, as the umbilical cord is clamped and the placenta delivered. But if the uterus fails to contract, as it does in up to 15 per cent of cases, those vessels can flow like a tap. A woman can bleed out in an hour.
"In the developing world, where I work, you have a one-in-100 chance of dying in childbirth because of it," says Malcolm Potts, an obstetrician and scientist at the University of California at Berkeley.
Of the estimated 1,000 women who die from pregnancy-related causes in the world each day, postpartum hemorrhaging kills more than any other complication.
"One woman dies of PPH every seven minutes," Dr. Potts says.
In the industrialized world, it has been 75 years since drugs came along to jump-start contractions and stop postpartum bleeding, and the better part of a century since women regarded childbirth as a reason to write a will. But those medications require money, refrigeration, medical skill and equipment to be administered, making them unavailable to millions of women living where electricity remains a luxury.
Yet several years ago, doctors discovered a drug that could help save their lives, a simple 10-cent tablet that needs no cold storage or special devices to deliver. But the medicine, called misoprostol, also can induce labour and abortions, and it's mired in a triad of controversy - political, ethical and medical. Access to it for women delivering, 45 million of whom will give birth this year without a trained assistant, remains patchy.
Some countries see it as a moral danger. The Philippines has banned it. Experts at the World Health Organization see its use for postpartum bleeding in the community as a potential medical danger. But many on the front lines of safe motherhood - a few now embroiled in a very public dispute with the WHO - believe misoprostol is the best weapon there is to fight PPH in developing countries.
It could revolutionize obstetrics the way penicillin revolutionized treatment for infections. Dr. Malcolm Potts, who heads Berkeley's Bixby Center of Population Health and Sustainability.
The WHO worries that pregnant women, or those who care for them, will misuse misoprostol, which can have disastrous consequences if taken at the wrong time at the wrong dose. It insists that the drug needs further safety studies and may yet prove to have serious side effects.
Metin Gülmezoglu, medical officer in the WHO's department of reproductive health and research, put it this way: "In medicine, there are things that look like they may be so straightforward, and they turn out not to be ... and that can cause hundreds of thousands of deaths. That's what we're trying to avoid here."
Hazem El-Refaey, an Egyptian-born scientist, obstetrician and gynecologist now at the Chelsea and Westminster Hospital in London, pioneered the drug's use in obstetrics. But he suspects that politics undermine efforts to make misoprostol widely available.
"If you present it around the world as a life-saving drug for postpartum hemorrhaging, it will be available in every hut to treat postpartum hemorrhaging - and it will also be available in every hut for abortion," he says. "There is no other pill like it."
It also may be that no other pill has the power to force a global reckoning on the ties between a mother's well-being and a woman's reproductive rights.
In the lead-up to this week's G20 and G8 summits in Southern Ontario, where maternal health is a key focus, Stephen Harper's Conservative government worked to separate the two issues. Canada has pledged new money and rallied international commitment to improve the health of mothers worldwide, but Ottawa says it will not support any initiative that involves abortion. Recent polling by Nanos Research suggests that Canadians disagree; 67.7 per cent said women in countries receiving aid from Canada should have access to safe abortions.