Last year, at a rural health clinic in Rwanda, I watched women queuing nervously for pregnancy tests and jumping for joy when they received the results. They were joyous because the test was negative. These women knew they would not have to risk their lives by having a baby because of an unintended pregnancy.

The shocking reality is that pregnancy and childbirth continue to be a death sentence for a third of a million girls and women in the developing world every year. In Afghanistan, a girl is more likely to die in pregnancy and childbirth than she is to attend secondary school.

Giving women access to family planning so they can decide whether, when and how many children they have, is one of the most effective ways to tackle the scandal of maternal death that afflicts the world’s poorest women.

That is why, as part of our efforts to put girls and women at the heart of our work, one of the UK’s top development priorities this year is to rally a renewed global emphasis on family planning.

Together with the Bill & Melinda Gates Foundation, the UK Government will host the first ever global family planning summit in July. The summit aims to bring together leaders from developing and developed countries, foundations, civil society groups and the private sector behind a simple vision: to give women in the developing world the same access to lifesaving family planning as women in the developed world.

Our aim is to reduce by half the number of women who currently want contraception but cannot access it. Unprecedented political commitment and resources will be called for at the summit but the return on our collective investments will be huge. If we can enable 120 million more women and girls in the world’s poorest countries to access contraception by 2020, around 300,000 fewer girls and women will die in pregnancy and childbirth, and three million fewer infants will die from complications in their first year of life.

The benefits of family planning go far beyond the number of lives it saves. Thousands of teenage girls drop out of school in developing countries every year due to pregnancy. In fact, half of all the world’s first-born children are born to adolescent girls, the majority of whom are married. When girls are able to delay the age of their first pregnancy, including through using contraception, they are far more likely to complete their education and gain the skills they need to work their way out of poverty.

I will not shy away from recognizing that one of the benefits of improving access to family planning is smaller family size. Discussing fertility and population dynamics has been taboo for political leaders for too long. Studies find that when women and couples have the ability to decide for themselves, the number, spacing and timing of their children, fertility rates fall and families are better able to increase their household income and invest more in their existing children. We must not allow out-dated taboos to get in the way of helping women to make decisions about their own lives.

Where overall fertility is very high, it is inevitable that national governments will feel the strain of ensuring access to key basic services, such as healthcare, education, water and sanitation. Natural resources are also likely to come under increasing pressure, and it is the poorest families, those who are most reliant on the natural environment for their basic survival, who are likely to feel the greatest impact.

In short, family planning is one of the most cost-effective investments a country can make in its future. It saves women’s and children’s lives, drives broader economic growth and development and offers incredible value for money. Every US$1 spent on family planning services leads to savings in country budgets of up to $6 in sub-Saharan Africa and $13 in South Asia.

Yet, despite the wide range of benefits family planning provides, progress in enabling women and girls to access contraception has largely stalled over the past two decades. The British Government is proud to be playing its part to put family planning back on the global community’s agenda and help more women decide for themselves whether, when and how many children to have.

We know that millions of couples in developing countries who want to delay or avoid a pregnancy do not have access to effective methods of contraception. It is high time their needs were met.