Research into the effect of age and the number of times women undergo assisted reproduction technology (ART) shows that for younger women, the overwhelming majority achieve a pregnancy within the first two attempts, whereas women over the age of 40 had a more consistent, but lower, pregnancy rate of about 20% throughout their first four attempts.
Mr Simon Hong told the 24th annual meeting of the European Society of Human Reproduction and Embryology in Barcelona July 8th: "The purpose of this study was to try to identify, at least in our practice, if a patient in a certain age group should repeat a cycle and how many. We found that the overwhelming majority of women who became pregnant (96%) achieved pregnancy by their second attempt, although the probability of a pregnancy after the third and fourth attempts remains encouraging. These results confirm that there is negative correlation between achieving pregnancy and increasing the number of attempts. Nonetheless, for all patients undergoing ART treatment, failure of the first attempt justifies at least one additional cycle."
Mr Hong is a researcher at the Center for Reproductive Medicine and Infertility, Cornell University (New York, USA), which is headed by Professor Gianpiero Palermo who pioneered the intracytoplasmic sperm injection (ICSI) technique.
Mr Hong and his colleagues analysed 8,970 ICSI cycles carried out in 6,719 patients treated between September 1993 and December 2007. The women were categorised into three groups: those aged 35 or younger, those aged 36-39, and those aged 40 and over. The average age was 36.5. Mr Hong examined the number of women achieving pregnancy at each attempt in each age group.
"The overall pregnancy rate, regardless of the mothers' age, was 39.2% -- 3,515 pregnancies out of 8,970 cycles. The highest number of ART attempts was eight, but only a handful of patients had six or more attempts," said Mr Hong.
Among all patients of all ages who achieved a pregnancy, 79.7% were successful in their first attempt, 16% in their second, and 3.4% in their third. When Mr Hong looked at the different age groups, those aged 35 and under had an overall pregnancy rate of 50.8%. In this age group, 53.7% of women became pregnant at their first attempt, and this decreased to 43%, 33%, 23% and 18.2% at the second, third, fourth and fifth attempts, respectively. There were no successful pregnancies beyond the fifth attempt.
In the 36-39 age group, the overall pregnancy rate was 39.5%. Again, there was a steady decrease from 41.5% at the first attempt to 25% at the fourth attempt. In women aged 40 and over, the overall pregnancy rate was 24.1%, ranging from 24.6% to 18.5%, and there were no significant differences in the proportion of women becoming pregnant between the first and the fourth attempts.
Mr Hong said: "We observed a more consistent pregnancy rate in the older age groups starting at 36 years. This is probably because older women have a lower pregnancy rate from the time of their first attempt, and this rate remains consistent thereafter. It is possible that the incidence of embryo aneuploidy in this age group is the over-riding factor affecting pregnancy outcome in this age group.
"For the group aged 36-39, the pregnancy rate was 25% at the fourth attempt; however, it only includes four pregnancies out of 16. The large majority of pregnancies were evenly distributed between the first three attempts. For the group aged 40 and over, a consistent pregnancy rate of about 20% throughout the first four attempts was observed. From this, it seems that for the older age groups, the number of attempts that provide a consistent pregnancy rate extends from two to four.
"An ART cycle is financially burdensome, but most importantly an emotional endeavour. It also requires exposure to medications and to, although minor, a surgical procedure. From our findings, it appears that younger patients undergoing two ART attempts benefit from the highest chances of pregnancy. While women in the higher age groups (aged 36 and older) may benefit from a successful outcome when undergoing a third or perhaps fourth attempt."
Mr Hong concluded: "It is difficult to determine at which attempt a patient should end her pursuit to conceive through assisted reproduction. We feel that couples should be given all available information to make the most informed decision possible. Therefore, we believe that couples should be offered counselling that describes the chances of a successful pregnancy at each individual ART attempt for their specific age group."
Materials provided by European Society for Human Reproduction and Embryology. Note: Content may be edited for style and length.
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