Ivanka Trump’s endorsement of an anti-abortion governor has been seen as evidence the first daughter and presidential advisor is opposed to abortions.

Donald Trump’s eldest daughter, who has routinely tried to portray herself as a defender of women’s equality, has lent her backing to Kim Reynolds and visited Iowa to campaign for the Republican.

Ms Reynolds has been hailed by conservatives for signing the strictest abortion ban in the US in June.

The bill bars doctors from performing most abortions after a fetal heartbeat can be detected which is usually around six weeks into a pregnancy. This is a period of time that often passes before a lot of women know they are pregnant.

The law was soon challenged in court – with a judge placing a temporary injunction on it.

In October, a poll by the Des Moines Register found a majority of Iowans thought the bill was too harsh.

Ms Trump, who serves as an unpaid senior adviser to her father, said she was “proud” to be in Iowa’s capital Des Moines to “support” Ms Reynolds.

“As the FIRST female Governor of Iowa, @IAGovernor cut taxes, balanced the budget (with a 127 m surplus!) & fostered a pro-growth environment where incomes are rising & unemployment is 2nd lowest in the Country! Proud to be in Des Moines to support my friend. Vote for Reynolds!” the 37-year-old tweeted.

Ms Reynolds became acting governor of the state last year when Terry Branstad resigned to become US ambassador to China. She is running against the Democrat Fred Hubbell, a wealthy businessman who has never run for office.

The race is very close and a Des Moines Register poll found 43 per cent of likely voters support Mr Hubbell, while Ms Reynolds support is at 41 per cent. If Ms Reynolds wins, she will be the first woman elected as governor in Iowa.

Ms Trump has not been clear about her stance on abortion – an issue which has become increasingly partisan and divisive in America under the Trump administration.

When asked to take a clear yes-or-no position on the issue in a 2016 radio interview, Ms Trump said: “I don’t talk about my politics”.

But the former head of Planned Parenthood has claimed Ms Trump and her husband Jared Kushner offered her women’s health group extra funding if it agreed to stop providing abortion services – an offer she said felt like “a bribe”.

Despite Mr Trump’s track record of making sexist comments about women and hostility towards women’s rights, Ms Trump has frequently touted herself as an advocate of female empowerment.

Taking the stage at the Republican National Convention in 2016 to speak on behalf of then-candidate Mr Trump, she presented herself as the champion of women's rights in her father's future presidency.

She claimed she stood up for working women and mothers, arguing for equal wages, better child care and paid family leave. But last August she backed the scrapping of Obama-era policy that would have required business owners to document how much they pay their workers alongside their gender, race and ethnicity.

Critics have routinely branded Ms Trump “complicit”, a "fake” or “plastic” feminist, and a "hypocrite".