A new research study conducted at a single fertility clinic led by researchers from Centre for Reproductive Medicine, UZ Brussel (Brussels, Belgium), has found that women undergoing fertility treatment who are less than 38 years of age are more likely to give birth to a live baby after ICSI (intracytoplasmic sperm injection) if 11 or more eggs have been retrieved from their ovaries in one ovarian stimulation cycle. The results of the study were presented recently at the annual conference of the European Society of Human Reproduction and Embryology.
The study led by Dr Dominic Stoop, a senior clinical fellow and gynaecologist, and Ms Eleonora Jansen, an obstetrics and gynaecology resident in training, has revealed that there is a gradual increase in the incidence of preclinical abortion, miscarriage and overall pregnancy loss during the first trimester after the age of 35. The incidence for these events is almost the same until the age of 35.
According to the results of the study, until the age of 37 the average rates of preclinical abortion, miscarriage and overall pregnancy loss in the first trimester were 8.5%, 6.8% and 16.9% respectively. These rates increased to 13.8%, 16.6% and 33.8% respectively between the ages of 38-40. A further increase to 21.6%, 31.6% and 56.7% respectively was identified between the ages of 41-43.
Data on ICSI collected prospectively for nearly two decades at UZ Brussel from 1992 to 2009 was analysed by the scientists. The dataset comprised of a total of 23,354 ovarian stimulation cycles.
Dr. Stoop stated,
“To our knowledge, there have been no other studies reporting on live birth rates after ICSI in relation to the number of eggs retrieved that also includes the risks for preclinical abortion and miscarriage for women with a positive pregnancy test after ICSI treatment. By focusing only on ICSI treatments, we know the exact number of mature eggs retrieved, fertilised and implanted.”
The study has also revealed that the ovarian response is significantly linked to the live birth rate. The best chances of a successful pregnancy were in women who had 11 or more eggs retrieved after stimulation. Women who had 6-10 eggs retrieved had a 4.3% lower chance of a live birth than those with 11 or more eggs. Again, in comparison with women who had the best chances, a notable decline of 16.4% in the chance of a live birth was observed in women with only 1-5 eggs.
It is also worthwhile to mention that the age of the patient was not found to be related to the risk of ectopic pregnancy. The rate of ectopic pregnancy in the analysed dataset was found to be 1.9% per cycle which is almost the same as that seen in the general population.
Ms Jansen concludes:
“This analysis provides interesting information regarding the outcome for patients undergoing an ICSI treatment. It demonstrates the strong correlation between ovarian response and the chances of achieving a live birth after ICSI. It enables the fertility specialists as well as the patients to calculate the chances of a pre-clinical abortion, a miscarriage or a live birth.”
“The study also shows a strong increase in first trimester pregnancy loss after the age of 38, with an even more pronounced increase after the age of 40. These findings illustrate the important risks associated with the delay of childbirth to more advanced ages, especially until after the age of 38.”
“The finding that the risk of ectopic pregnancy is unrelated to a woman’s age, and is similar to that seen in the general population, is reassuring news for women undergoing fertility treatment.”
Source: European Society of Human Reproduction and Embryology
Written by Anne Hudsmith