OBJECTIVE: Delaying embryo transfer (ET) enables us to select among the embryos available for transfer and is associated with positive effects on implantation and pregnancy outcomes. However, the optimal day for ET of human cleavage-stage embryos remains controversial. METHODS: A retrospective study of 3,124 in vitro fertilization/intracytoplasmic sperm injection cycles (2,440 patients) was conducted. We compared the effects of day 2 and 3 ET on rates of implantation and pregnancy outcomes between young maternal age (YMA; <38 years old, n=2,295) and old maternal age (OMA; ≥38 years old, n=829) patient groups. RESULTS: The YMA and OMA groups did not differ in terms of patient characteristics except for the proportion of unexplained factor infertility, which was significantly greater in the OMA group, and the proportion of arrested embryos, which was significantly greater in the YMA group. However, the biochemical pregnancy, clinical pregnancy, ongoing pregnancy, abortion, and implantation rates per cycle were not significantly different between day 2 and 3 ET in the YMA group or the OMA group. CONCLUSION: We suggest that offering patients the opportunity to decide which day would be suitable for ET could be part of a patient-friendly protocol that takes into consideration an infertile woman's circumstances and work schedule by allowing ET to be performed on day 2 instead of the traditional transfer on day 3.
Appointments and Schedules ; Embryo Transfer* ; Embryonic Structures* ; Female ; Humans ; In Vitro Techniques ; Infertility ; Maternal Age* ; Pregnancy ; Pregnancy Outcome ; Retrospective Studies ; Spermatozoa

OBJECTIVES: The escalating burden of cardiovascular disease (CVD) is a critical public health issue worldwide. CVD, especially acute myocardial infarction (AMI) and stroke, is the leading contributor to morbidity and mortality in Korea. We aimed to develop algorithms for identifying AMI and stroke events from the National Health Insurance Service (NHIS) database and validate these algorithms through medical record review. METHODS: We first established a concept and definition of “hospitalization episode,” taking into account the unique features of health claims-based NHIS database. We then developed first and recurrent event identification algorithms, separately for AMI and stroke, to determine whether each hospitalization episode represents a true incident case of AMI or stroke. Finally, we assessed our algorithms’ accuracy by calculating their positive predictive values (PPVs) based on medical records of algorithm- identified events. RESULTS: We developed identification algorithms for both AMI and stroke. To validate them, we conducted retrospective review of medical records for 3,140 algorithm-identified events (1,399 AMI and 1,741 stroke events) across 24 hospitals throughout Korea. The overall PPVs for the first and recurrent AMI events were around 92% and 78%, respectively, while those for the first and recurrent stroke events were around 88% and 81%, respectively. CONCLUSIONS We successfully developed algorithms for identifying AMI and stroke events. The algorithms demonstrated high accuracy, with PPVs of approximately 90% for first events and 80% for recurrent events. These findings indicate that our algorithms hold promise as an instrumental tool for the consistent and reliable production of national CVD statistics in Korea.