Leveling the playing field for grandfather’s sperm

To the Editor:

A recent publication by Frattarelli et al., found that sperm from males age 50 or over resulted in a lower percentage of live deliveries, even when using a donor oocyte model to negate the adverse effect of maternal oocyte age (1). These data reached a different conclusion compared to an earlier publication by another group using the donor oocyte model

Risk of birth defects increased in pregnancies conceived by AHR

To the Editor:

In a recent publication, using the Niday Perinatal Database from 82 primary and tertiary centers in Ontario for 2005, El-Chaar et al found that assisted human reproduction (AHR) procedures increase the risk of birth defects in a retrospective cohort design (1).  

Evidence of absence or absence of evidence? A reanalysis of the effects of low-dose aspirin in in-vitro fertilization

To the Editor:

We read with respect the article by Ruopp et al. (1) that has questioned the methodological approach of our previously published review (2) on the use of aspirin in in vitro fertilization cycles. We disagree with the authors in that random-effects models should only be used in the absence of inter-study heterogeneity. With fixed-effects models, it is assumed that there is a sole common effect estimates for all studies, i.e., the true effect of treatment, in both magnitude and direction, is the same value in every study.

Less may, indeed, be less: multi-collinearity in studies of ovarian reserve

To the Editor:

We read with interest the recent paper by Pal et al. (1), in which they conclude that their data and accruing literature suggest adverse influences of “excess” gonadotropin use on IVF outcomes. While we applaud their attempt at tackling a potentially very important question, we disagree with interpretation of data and conclusions in the manuscript.