Human cleavage-stage embryo vitrification is comparable to slow-rate cryopreservation in cycles of assisted reproduction.

Objectives: To compare embryo survival, pregnancy and implantation rates after cryopreservation of human cleavage-stage embryos with slow-rate cryopreservation or vitrification.

Study Design: 262 patients, attending for assisted reproduction, were prepared for oocyte retrieval using standard controlled ovarian hyperstimulation protocols. Excess embryos were cryopreserved on day 3 either by vitrification, or slow-rate cryopreservation in a programmable freezer.

First trimester screening for trisomy 21; Do the parameters used detect more pathologies than just Down syndrome?

Objective: To assess the value of first trimester maternal serum free beta human chorionic gonadotropin (beta hCG), pregnancy-associated plasma protein (PAPP-A) concentrations and nuchal translucency (NT) as predictors of pregnancy complications.

Design: A retrospective collaborative study of beta hCG, PAPP-A and NT between 10 and 14 weeks of pregnancy in patients in whom pregnancy was followed to term. Nuchal translucency, maternal serum PAPP-A and free beta hCG concentrations were measured in 1779 women with singleton pregnancies and without aneuploidies.