The woman received a deceased donor uterus transplant, had the baby and then had the uterus removed. (I don't think the uterus removal is mentioned in this story, I read it elsewhere.) She had the transplanted uterus removed to prevent transplant complications (and I assume one baby was what she wanted so she didn't need it.).
https://www.nytimes.com/2018/12/05/health/uterus-transplant-birth.html?partner=rss&emc=rssA woman who received a uterus transplanted from a deceased donor has given birth to a healthy child, researchers in Brazil said on Tuesday. It is the first such birth to be reported.
Uterine transplants from living donors have succeeded; at least 11 babies have been born this way since 2013. But a viable procedure to transplant uteri from deceased women could drastically increase the availability of the organs.