The statistic is based on reported abortions. It is probably much, much higher.

aprox 700 yearly maternal deaths annually

https://www.cdc.gov/reproductivehealth/maternalinfanthealth/pregnancy-relatedmortality.htm

2017- 3.8 million US babies born

https://www.washingtonpost.com/national/health-science/the-big-number38-million-babies-were-born-in-the-us-last-year-thats-a-drop/2018/05/25/ce96af5a-5f6f-11e8-a4a4-c070ef53f315_story.html

maternal mortality rate of .018%

332,757 abortions reported in 2017

http://www.numberofabortions.com/

700 maternal deaths vs 332,757 infant/fetal deaths