The US is understood to have written to UN member states urging them to join a “growing coalition” of countries rallying against abortion, in what seems to be the latest attempt by the Trump administration to rollback women’s rights.

A letter, seen by the Guardian, is believed to have been sent to governments deemed sympathetic to the administration’s view on reproductive health.

In the letter signed by the secretary of state Mike Pompeo and health and human services secretary Alex Azar, governments are encouraged to sign a joint statement opposing “harmful” UN policies that promote sexual and reproductive health and rights.

The statement will be presented to a high-level meeting on universal health coverage at the UN general assembly on Monday, says the letter, which suggests multilateral agreements have been misinterpreted to promote pro-choice policies.

“As a key priority in global health promotion, we respectfully request that your government join the United States in ensuring that every sovereign state has the ability to determine the best way to protect the unborn and defend the family as the foundational unity of society vital to children thriving and leading healthy lives,” reads the letter.

“We remain gravely concerned that aggressive efforts to reinterpret international instruments to create a new international right to abortion and to promote international policies that weaken the family have advanced through some United Nations fora.

The opening of the UN general assembly at the organisation’s headquarters in New York. Photograph: Li Muzi/Xinhua/Barcroft Media

“Evidence of this is found in references throughout many multilateral global health policy documents to interpret ‘comprehensive sexuality education’ and ‘sexual and reproductive health’ and ‘sexual and reproductive health and rights’ to diminish the role of parents in the most sensitive and personal family-oriented issues. The latter has been asserted to mean promotion of abortion, including pressuring countries to abandon religious principles and cultural norms enshrined in law that protect unborn life.

“These approaches undermine our shared commitment to sustainable development and to achieving health for all, leaving no one behind.”

Efforts to advance these policies at the UN, specifically at the World Health Organization, were “disturbing and must be challenged”, the letter said.

The message called on governments to sign a joint statement – similar to one delivered to the World Health Assembly in May – that would be presented at Monday’s meeting, “and to work together to achieve an outcome document … that reflects our shared values”.

The May statement was signed by the US, Brazil, Egypt, Saudi Arabia, Indonesia, Haiti, Ghana, Nigeria and Iraq. It stated that references to sexual and reproductive health “cause confusion and misunderstanding”. It called on the WHO to “focus on terms that enjoy broad consensus among member states”.

Requests for comment on the authenticity of the letter from the US State Department and Department of Health and Human Services went unanswered.

The Trump administration has made repeated attempts to dilute and remove language from decades-old UN agreements.

Intense lobbying by US officials in April resulted in the removal of references to sexual and reproductive health from a UN security council resolution on combatting rape in conflict.

The US previously attempted to water down language and remove the word “gender” from UN documents.

“This letter just shows how they are trying to erode international consensus and roll back the clock for women and girls,” said Shannon Kowalski, director of advocacy and policy at the International Women’s Health Coalition.

“It’s not just abortion that they care about, they care about women’s ability to exercise autonomy over their bodies and about denying them critical access to the services they need.”

That Pompeo and Azur both signed the letter suggests an escalation of the US strategy to undermine policy statements, she added.

Keifer Buckingham, senior policy adviser for international public health at the Open Society Foundations, said that rather than an escalation, “it could be them just putting out in public what they have been doing in private”. She said the US was effectively sending a message of “if you’re not with us, you’re against us”, which could have funding implications.

• This article was amended on 24 September 2019 because, after publication, the Department of Health and Human Services got in touch to confirm the authenticity of the letter.