According to a recent study in Human Reproduction, women who produce a low number of oocytes during in vitro fertilization (IVF) seem to have an increased risk of miscarriage.
Researchers at the University of Birmingham looked at data from the Human Fertilization and Embryology Authority, collected from 1991 to June 2008, covering 402,185 stimulated fresh IVF cycles and 124,351 resulting pregnancies.
A strong association between the number of oocytes retrieved per IVF cycle and the clinical miscarriage rate was found. Logistic regression identified 3 cut-off points where the probability of clinical miscarriage fell: 4, 10, and 15 oocytes. Women who produced <4 oocytes had a miscarriage rate of 20%; the miscarriage rate was 15.5% for women who produced between 4 and 9 oocytes; and women with 10 to 14 oocytes had a miscarriage rate of 13.8%. No increase in miscarriage risk was found in women who produced very high numbers of oocytes (>20 oocytes). The lowest risk of miscarriage was found in women younger than age 38, with primary infertility without a female cause, and who produced more than 3 oocytes.
The investigators said that the data were limited by a lack of information on the total gonadotropin consumption and confounders such as body mass index. They also concluded that the high rate of miscarriage is more than likely associated with a decline in the quality of the oocytes.
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