Increasing the number of cycles of in vitro fertilization (IVF) to more than three or four may boost success rates for infertile women up to the age of 42, according to a new study published in JAMA, with six IVF cycles producing the highest live birth rates.
IVF is a type of aided reproductive technology (ART) that consists of manually fertilizing an egg with sperm in a lab dish and shifting the embryo to the uterus.
According to Resolve: The National Infertility Association, there is a common 20-35% rate of success per cycle of IVF in the US, with the maximum per-cycle success standing at about 40%.
Research leader Debbie A. Lawlor and her team observe that the greater part of women prefer to stop IVF after going through around 3 or 4 unsuccessful cycles.
On the other hand, their research indicates ongoing IVF after this point could increase success rates to around 68%.
To arrive at their results, Lawlor and colleagues examined data of 156,947 females from the UK who went through 257,398 cycles of IVF involving either fresh or frozen embryo transfers among 2003-10. Follow-up carried on until June 2012.
Women in the research were a average age of 35 at the start of therapy, and the median infertility length for all cycles was 4 years.
6 IVF cycles produced greatest live birth rates
All round, the live birth rate for the initial IVF cycle for the women was 29.5%, and there was a live birth rate of a minimum of 20% for each cycle up to the fourth cycle.
The team identified that the cumulative prognosis-modified live birth rate over all cycles of IVF ongoing to rise right up till the ninth cycle, with a live birth rate of 65.3% recognized for the sixth cycle.
Among females below the age of 40 who went through IVF with their own oocytes, or eggs, the live birth rate was 32% for the initial cycle and was at least 20% up to the 4th cycle. For the 6th cycle, however, a live birth rate of about 68% was obtained.
Females aged 40-42 years had a 12% live birth rate for the initial cycle of IVF, while a live birth rate of 31.5% was obtained with 6 cycles.
For females above the age of 42, however, the live birth rates for each cycle were less than 4%, and among women who made use of donor eggs for IVF, success rates did not vary by age.
Live birth rates were reduced for women with untreated male partner-related infertility, in comparison with those whose infertility was triggered by other aspects, though this distinction was offset by previous therapy with sperm donation or intracytoplasmic sperm injection (ICSI).
The investigators note that females under the age of 40, those who used donor eggs and females with male partner-related infertility that was treated with sperm donation or ICSI obtained live birth rates following four or five cycles that were identical to those of women who conceive normally within one year. “It must be noted, however, that, in these females, five cycles had taken a median of 2 years,” they add.
Furthermore, the team identified that the number of eggs recovered after ovarian stimulation in one IVF cycle has no effect on the live birth rates in subsequent cycles. They say this discovering is essential as infertile couples are usually told that their possibilities of success with future IVF cycles may be hindered if only a few or no eggs are recovered in a previous cycle.
Leaving comments on their overall outcomes, the researchers say:
“These results support the usefulness of increasing the number of IVF cycles beyond 3 or 4.”