Thousands of women in Africa will die in pregnancy and childbirth as a result of cuts to the UK’s overseas aid budget, ministers have been warned.

According to an internal assessment by civil servants, almost 200,000 more women will also face unsafe abortions.

Their report reveals the impact of cuts this year to the overseas aid budget.

The Foreign Office says its budget for low-income countries has been cut in the short-term to hit a savings target, but will then nearly double.

The internal document says a 76% cut in aid for Afghanistan will leave some of the world’s most vulnerable women and girls without critical services.

And half a million women and children in Yemen will not receive healthcare.

The conclusions come in an assessment made by Foreign Office civil servants earlier this year, to inform ministers before they decided what to cut.

Andrew Mitchell, the development minister, gave it to the International Development Committee as part of his efforts to make UK aid spending more transparent – as it used to be before the Department for International Development was merged with the more secretive Foreign Office.

Previous governments have rarely published such detailed calculations about the impact of their spending reductions.

In the assessment, the Foreign Office outlines some of the headline cuts to the department’s Overseas Development Assistance budget worth more than £900m for this year.

Many of these reductions were imposed on the Foreign Office after the Treasury allowed the Home Office to spend about a quarter of the aid budget housing refugees in Britain.

This is allowed under international rules for the first year of a refugee’s stay in the UK.

But the arrival of so many refugees and asylum seekers in small boats over the Channel has sent the costs of hotel bills soaring.

And that has meant less can be spent on the government’s priorities overseas.

The assessment said that as a result of 76% cuts in aid to Afghanistan, the Foreign Office “will not be able to support critical services for women and girls… reducing funding will potentially leave some of the most vulnerable women and girls in the world without critical services”.

Across Africa, it said that reductions to the Women’s Integrated Sexual Health Programme would reduce protection for women with “the number of unsafe abortions averted from nearly 300,000 to approximately 115,000; number of maternal deaths averted will drop from 2,531 to just over 1,000”.

In Yemen, it said that half a million women and children in Yemen will not receive healthcare and “fewer preventable deaths will be avoided”. “It may cause lasting damage to health systems in Yemen, if other donors are unable to fund,” it said.

In Somalia, the Foreign Office will have to “delay this year, and potentially stop altogether” a programme to counter female genital mutilation.

And in South Sudan, cuts the humanitarian budget will mean “27,000 children suffering from severe acute malnutrition will go untreated, of which 12% (3,000) could die”.

To try to soften the blow of these cuts, the Foreign Office has used “in-year underspends and other resources” to find a little more money to spend on aid this year, including a further £41m for Afghanistan, £32m for Yemen, £30m for Syria and £30m for Somalia.

And in his letter to the Development Committee, Mr Mitchell emphasised that aid spending would increase next year, with almost double being allocated to Africa.

But Sarah Champion MP, chair of the International Development Committee, said the cuts were “intolerable” and would have a “terrible impact”.

This astonishingly honest assessment of the real impact makes grim reading. It is a litany of the people – living in poverty, suffering hunger, women, girls, disabled people – who will no longer be supported by the UK’s direct aid spending,” she says.

Ian Mitchell, senior policy fellow and co-director of Europe at the Center for Global Development, said: “The abrupt nature of the budget reduction imposed by Chancellor Jeremy Hunt last year meant that [the Foreign Office was] unable to protect the poorest or most vulnerable groups; or even stated government priorities like girls’ education or climate.”

A spokesperson from the Foreign Office said UK aid spending would rise to £8.3bn next year, with a focus on dealing with humanitarian crises, protecting women and girls and supporting vulnerable people, “while delivering value for money for taxpayers”.

“While the budget for low-income countries has had to be reduced in the short term to achieve our savings target – it is due to nearly double for these countries the year after, including in Africa where aid will rise from £646m to £1.364bn.”