An article in the October 2012 issue of the medical journal Obstetrics & Gynecology examines factors which lead to good birth outcomes after assisted reproductive technology procedures (ART). IVF accounts for 99% of the ART procedures performed in the U. S.
They surveyed single live births at term among the live births (444,909) from ART procedures in the U. S. from 2000 to 2008. The proportion of good outcomes increased over those years. Factors in better outcomes were one previous birth, transfer of fewer than three embryos and the presence of fewer than three fetal hearts on the 6-week ultrasound were associated with a good outcome among singletons.
Non-Hispanic black race, tubal factor infertility, uterine factor and ovulation disorders were associated with reduced odds for a good outcome.
This trend to better outcomes over this period of time mirrors the trend to transfer fewer embryos to avoid multiple pregnancy and the possible morbidity from gestational sacs which do not progress, the so-called vanishing twin.