US is one of just 8 countries where maternal death rates are getting worse (CHARTS)

Number 55.

That’s what the United States ranks in the latest Gender Inequality Index (GII) by the United Nations Development Program. It's among 155 nations that had available data.

The larger the rank number, the worse the equality for women.

Fifty-fifth is a bad spot for the US, especially compared with the country's far better overall Human Development Index (HDI) rating — eighth among 188 nations.

And unlike many other countries, America’s gender gap is not improving. The US actually fell from 47th place in the previous GII, pointing to some underlying trends that are disturbing for women.

What's alarming about these two findings is this: Overall, the Human Development Index shows life in the US is fairly decent. But in terms of gender equality — taking into account reproductive health, empowerment and labor participation — the US is falling fast. Of other countries in the top 10 of the Human Development Index (HDI), only the Netherlands slipped in its gender equality ranking, and then not as much as the US.

What's behind the US's falling rank in the Gender Inequality Index? Maternal mortality.

The UNDP finds an increase of maternal mortality ratio from 21 to 28. That means 28 women now die from pregnancy- or childbirth-related causes for every 100,000 live births.

That number has more than doubled in the past 25 years. UNDP data shows the US maternal mortality ratio in 1990 was 12 women per 100,000 live births. A CNN report published earlier this month pointed out that the US is one of only eight countries in the world, including Afghanistan and South Sudan, where the ratio is going up.

Afghanistan and South Sudan are recovering war zones, not countries in the top 10 of the UNDP's overall ranking for liveability. While other countries have improved in both maternal mortality ratio and liveability in tandem, the maternal mortality ratio of the US is heading the opposite direction. The animated chart below shows the changes in maternal mortality ratio and the Human Development Index from 1990 to 2013 for the 10 countries with the highest index. 

Click the 'play' button to start the animation.

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But UNDP's report shows more cracks in the facade of “very high human development” in the US when it comes to gender equality. UNDP lumps 49, mostly developed Western countries, in a category of their own. Of the 45 of those developed countries that have enough data to be on the Gender Inequality Index, the US ranks 40th.

This article originally appeared at PRI.org.