4. Blastocyst-stage and prediction of pregnancy.
This retrospective observational study was performed to define and validate metrics of embryo progression and morphology during extended embryo culture and to compare the effects of early cleavage (EC) vs. blastulation stages on clinical pregnancy. The study included one 1292 sperm injection and 842 IVF blastocyst-transfer cycles. The embryo progression index (EPI) was calculated as the area under the curve of total cell number (TCN) over time, by using observed TCN for cleavage-stage embryos and estimated blastocyst TCN according to morphology. The EPI from days 1-3 measured early cleavage, and blastulation was assessed by EPI over extended embryo culture. Blastocyst morphology was converted into numerical blastocyst quality scores (BQSs). Receiver operating characteristic curve analysis was used to evaluate predictors for clinical pregnancy. Per-cycle mean EPI and mean BQS for all embryos developing into blastocysts, as well as mean BQS of the transferred embryos, were significant predictors of clinical pregnancy in intracytoplasmic sperm injection and IVF cycles. Mean EPI for days 1-3 did not predict outcome. Early cleavage is a putative marker of embryo quality. Late-stage embryo development is more sensitive and specific in predicting clinical pregnancy than is early cleavage, supporting the use of extended embryo culture for embryo selection. The embryo progression index and BQS may also be used for this purpose.
Rehman KS, Bukulmez O, Langley M, Carr BR, Nackley AC, Doody KM, Doody KJ Late stages of embryo progression are a much better predictor of clinical pregnancy than early cleavage in intracytoplasmic sperm injection and in vitro fertilization cycles with blastocyst-stage transfer. Fertil Steril. 2007 May;87(5):1041-52.
5. Bed rest after embryo transfer?
This is a randomized controlled trial in women undergoing IVF to determine whether bed rest after embryo transfer leads to improved pregnancy rates (PR). Patients undergoing 164 cycles of IVF were randomized to 30 minutes of bed rest after embryo transfer or immediate discharge from the clinic. Clinical PR defined by visualized fetal heart beat and ongoing PR defined by viable intrauterine gestation beyond 11 weeks. The clinical and ongoing PR for both groups were 50% and 46.3%, respectively, with no statistically significant difference between the two groups. Thirty minutes of bed rest after embryo transfer does not improve PR.
Purcell KJ, Schembri M, Telles TL, Fujimoto VY, Cedars MI. Bed rest after embryo transfer: a randomized controlled trial. Fertil Steril. 2007 Jun;87(6):1322-6.