Today is Mother's Day, not only in the United States but in many other countries. Children of all ages are giving flowers, making breakfast, calling home.

This is as it should be. On my travels around the world, particularly to its poorest and most troubled places, I have learned that it is mothers who keep families together — indeed, who keep whole societies intact. Mothers are society's weavers. They make the world go round. Yet too often, the world is letting mothers down.

Becoming a mother — the rite of passage we celebrate — can carry a terrible burden of fear, anxiety and loss for many women and their families.

Women such as Leonora Pocaterrazas, 21, who not long ago died in childbirth in the mountain village of Columpapa Grande, Bolivia, leaving her husband to bring up three other children on his own.

Or Sarah Omega, just 20, who spent 18 hours in labor at a hospital in Kenya. Her baby died. But she survived, despite terrible injuries, determined to speak out so that others would not have to endure the same ordeal. "Life lost its meaning," she told U.S. lawmakers in 2008. Her testimony helped persuade Congress to commit more development aid to maternal health.

These are just two of the very personal stories behind the shocking statistics reported by the United Nations' Population Fund. The figures show the chasm between motherhood here and elsewhere, particularly in the developing world. It is a gap that the United Nations is determined to bridge.

In the rich world, when a mother dies giving birth, we assume that something went wrong. For women in the developing world, by contrast, dying in childbirth is simply a fact of life. In some countries, one woman in eight will die giving birth. Complications from pregnancy and childbirth are the leading cause of death among girls ages 15 to 19 worldwide.

In poor countries, pregnant women must often fend for themselves; they have no health care and nowhere to turn. They may struggle to find proper nutrition and work long hours in factories and fields until the day they go into labor. They give birth at home, perhaps with the help of a midwife who likely has no medical training.

I myself was born at home, in a small village in the Korean countryside. One of my childhood memories is asking my mother about a curious custom. Women who were about to give birth would gaze at their simple rubber shoes, which were kept by the back door.

My mother explained that they were wondering if they would ever step into those shoes again. Giving birth was so risky, they feared for their lives. In the United States itself, just 100 years ago, women were roughly 100 times more likely to die in childbirth than they are today.

We know how to save mothers' lives. Some simple blood tests, a doctor's consultation and someone qualified to help with the birth can make a huge difference. Add some basic antibiotics, blood transfusions and a safe operating room, and the risk of death can almost be eliminated.

Recent figures show that we are making progress in helping women throughout the world. Yet we have very far to go. Every year hundreds of thousands of women die in childbirth, 99 percent of them in developing countries.

That is why, as secretary-general, I have spoken out for the needs of mothers and pregnant women at every opportunity. Last month, at the United Nations, we launched a joint action plan with governments, businesses, foundations and civil society organizations to advance this vital cause. I am counting on people around the world to back us in ending this silent scandal.

No woman should have to pay with her life for giving life. On Mothers' Day, let us honor American mothers — and mothers around the world — by pledging to do everything we can to make motherhood safer for all.

Ban Ki-moon is the secretary-general of the United Nations.