IVF babies born using frozen embryo transfer are more likely to be larger and heavier, research has shown. Compared with “fresh embryos”, children born from frozen embryos are 1.6 times more likely to be oversized. French scientists examined babies born from frozen embryos and compared them with the “fresh” cohort of babies, in terms of mode of delivery, rate of premature birth, average child measurements, low birth weight and rates of perinatal mortality.

The researchers found that the average weight, height and head circumference of the cryo-babies were higher than those of the fresh babies. Of frozen embryo babies, 9.2% were “small-for-gestational-age”, compared to 14.8% of fresh IVF babies and 11.3% of naturally conceived babies.

“Frozen embryo transfer did not seem to adversely affect neonatal outcome,” says Dr. Sylvie Epelboin, from Bichat-Claude Bernard Hospital in Paris. “We are not sure why the cryo babies are heavier and larger, but we think it may have something to do with the hormonal hyperstimulation during the fresh cycles.”

Babies with high birth weight may face an increased rate of delivery by Caesarean section and obstetric intervention, which can both cause complications for both baby and mother. They can also cause significant complications in the birth, such as tearing and blood loss. ~ Science Daily, Jul 5