Here are the raw numbers claimed in the article:
From 2000 to the end of 2010, Texas’s estimated maternal mortality rate hovered between 17.7 and 18.6 per 100,000 births. But after 2010, that rate had leaped to 33 deaths per 100,000, and in 2014 it was 35.8.
The study these numbers are based on can be found here. The relevant graph was also posted to reddit here:

For comparison, here is the worldbank list of maternal mortality rate by country.
Countries that have a higher rate than Texas (in 2014, which is the relevant year), and their human development index from the same year:
- Argentina: Mortality: 52, HDI: 0.836 (very high human development)
The other 48 countries with very high human development according to HDI all have a lower maternal mortality rate, usually below 10. There are also a couple of countries with high human development that have a higher maternal mortality rate than Texas, for example:
- Malaysia: Mortality: 40, HDI: 0.779 (high human development)
- Cuba: Mortality: 39, HDI: 0.769 (high human development)
- Mexico: Mortality: 38, HDI: 0.756 (high human development)
- Brazil: Mortality: 44, HDI: 0.755 (high human development)
- Georgia: Mortality: 36, HDI: 0.754 (high human development)
The HDI is a commonly used metric to define the development status of a country, but not the only one. The IMF for example does not consider Argentina to be an advanced economy, but lists it as "emerging market and developing economy". Another categorization is the one by the CIA in the World Fact Book, which includes South Africa as developed country, which has a mortality rate of 138.