IVF Babies’ Birth Outcomes are Influenced by Treatment Type and Diagnosis of Infertility
In a new study published in Fertility and Sterility, researchers observed that differences in obstetrical outcomes for singleton pregnancies in patients using assisted reproductive technology (ART) depend on which techniques the patients used and their infertility diagnoses. These findings indicate that the uterine environment is perhaps the most important influence on the key outcomes of birth weight and length of gestation in ART pregnancies.
William Gibbons, MD and his colleagues Marcelle Cedars, MD and Roberta Ness, MD, MPH reviewed data collected by the Society for Assisted Reproductive Technologies (SART) for the years 2004 through 2006 and compared average birth weight and gestational age for singletons born as a result of standard IVF, IVF with donor eggs, and IVF with a gestational carrier. The data were further analyzed in relation to the patient’s primary diagnosis and whether donor sperm or sperm from the patient’s partner were used.
They found that the birth weight associated with standard In Vitro Fertilization (in which the patient carried the embryo created with her own egg) was greater than that associated with donor egg cycles and less than that in gestational carrier cycles. This finding held true even when other factors, including mother’s age, number of fetal heartbeats in the first trimester, and male factor were considered. While a diagnosis of male factor infertility did not affect birth weight or gestational age, every “female” diagnosis was associated with lower birth weight and, except for “unexplained” infertility, a reduced gestational age. Patients diagnosed with “uterine factor” had babies with the lowest birth weights and gestational ages.
The uterine environment as related to treatment type was also considered. In standard IVF an embryo is transferred to a woman who has just undergone controlled ovarian hyperstimulation, while in donor egg IVF and gestational carrier IVF, the embryo is transferred to a “natural” or unstimulated uterus. Therefore the researchers looked at IVF utilizing frozen embryo transfer- in which an embryo created with a patient’s own egg is transferred to her own unstimulated uterus- for additional information. They found that babies born of frozen embryo transfer cycles had markedly greater birth weights than those born as a result of standard IVF.
R. Stan Williams, MD, President of the Society for Assisted Reproductive Technology, observed, “The study shows that many interrelated factors affect the health of babies conceived using ART. Studies like this one increase our understanding and show us where further research may enable us to improve outcomes for our patients.”
Source: American Society for Reproductive Medicine