Author Interviews, Fertility, OBGYNE / 19.03.2019
IVF Birth Weights Show Steady Increase Over Three Decades
MedicalResearch.com Interview with:
Prof. Daniel R Brison PhD, FRCPath
Scientific Director
Department of Reproductive Medicine
Manchester University NHS Foundation Trust
Old St. Mary's Hospital
Manchester U.K and
Catherine M Castillo PhD
Maternal & Fetal Health Research Centre
Division of Developmental Biology and Medicine
School of Medical Sciences, Faculty of Biology, Medicine and Health
The University of Manchester
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: IVF conceived children have been known to have poorer birth outcomes when compared to spontaneously conceived children. Even when excluding twins and triplets, which result from more complicated pregnancies, IVF singletons have an increased risk of low birth weight and being born small for “dates” (length of gestation). This is important as studies carried out in non-IVF children show that low birth weight is associated with slightly higher risk of disease in later life.
We knew from the literature that birth outcomes differed within the IVF population depending on the type of treatment used; for example, singletons conceived from frozen/thawed embryos are born with higher average birth weights when compared to their fresh embryo conceived counterparts. Our research team wanted to investigate whether IVF practices and technologies per se (which have advanced quite rapidly over the years since 1978 when the first IVF baby was conceived) were associated with differences in singleton birth weight.
In attempting to quantify historical changes in laboratory practice going back as far as we could, we discovered that our outcome of interest – birth weight – had indeed increased notably throughout the time period covered by the available data. Besides observing an increase in birth weight of almost 180g over the study period (when accounting for child gender, gestational age and maternal parity), we also observed that frozen embryo transfer was associated with higher birth weight, and spontaneous fetal reduction and longer duration of infertility were associated with lower average birth weight.
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