The superovulated environment, independent of embryo vitrification, results in low birthweight in a mouse model
We found that superovulation of the recipient dams led to significantly lower fetal weight at term while blastocyst vitrification had no significant effect on fetal weight (1.43 ± 0.24 g fresh-natural, 1.30 ± 0.28 g vitrified-natural vs. 1.09 ± 0.20 fresh-superovulated, 0.93 ± 0.23 g vitrified-superovulated, P < 0.0001).
201. Fetal Weight, Cryopreservation and Superovulation [Forum/Discussion]
from: James Stanger (email@example.com ), Australia on 4/09/2017 10:55:59 AM Profession:
Superovulation may result in lower birthweights.
In an article in Biology of Reproduction, Weinerman et.al used a superovulation, pseudopregnant mouse model to examine the effects of superovulation and vitrification on fetal weights. They reported that superovulation (possibly by a reduction in placental blood flow) resulted in signification lower fetal birthweights from either fresh of vitrified mouse embryos. This is one more piece of information that transferring fresh embryos may result in the birth of lighter babies.// Given the associations between birth weight and adult illness (the Barker hypotheses - Fetal origins of adult disease) maybe more information needs to be given to IVF clients during workup as to whether the best embryos should be transferred either fresh or after vitrification.// Currently the best embryos are transferred into a superovulated uterine environment and therefore the majority of IVF babies are born from this environment. While the weight of all (most) IVF babies are recorded and documented, there is little appetite to follow these babies to adulthood. Imagine if in 40 years times, IVF is negatively correlated with coronary illness. At some point in time, a position cannot be defended when at the time of service, there was knowledge that Fresh but not frozen transfers were associated with lower birth weights. Far better going forward that the client was given the option for a fresh or frozen tranfer of their better embryos.