Study design and patients
This retrospective cohort study includes 41546 women who underwent fresh
or frozen-thawed embryo transfer between January 2014 and December 2019
in the Center for Assisted Reproductive Technology of Northwest Women’s
and Children’s Hospital, China. All the patients were followed up for
one year after embryo transfer. The study protocol was approved by the
ethics committee of Northwest Women’s and Children’s Hospital (No.
2019013). Because of the retrospective character of the study, informed
consent was waived. Patient data were anonymized. Women who underwent
the first cycle of fresh or frozen-thawed embryo transfer (FET) were
eligible to participate. We excluded women with no embryo transferred.
The women were divided into four educational categories according to the
level of education received (elementary school graduate or less, middle
school graduate, high school graduate, college graduate or higher).