Low and High-Normal Triplet Cytosine, Guanine Guanine Repeats Affect Ovarian Reserve and Fertility in Women Who Underwent Fertilization Treatment? Results from a Cross-Sectional Study.

Dynamic mutations in the 5' untranslated region of are associated with infertility. Premutation alleles interfere with prenatal development and increase infertility risks. The number of CGG repeats that causes the highest decrease in ovarian reserves remains unclear. We evaluated the effect of CGG repeat lengths on ovarian reserves and fertilization (IVF) treatment outcomes in 272 women with alleles within the normal range. CGG repeat length was investigated via PCR and capillary electrophoresis. Alleles were classified as low-normal, normal, and high-normal. Serum levels of follicle-stimulating hormone and anti-Mullerian hormone (AMH) in the follicular phase of the menstrual cycle were measured, and antral follicles (AFC) were counted. IVF outcomes were collected from medical records. Regarding CGG repeat length alleles, 63.2% of women presented at least one low-normal allele. Those carrying low-normal alleles had significantly lower AMH levels than women carrying normal or high-normal alleles. Low-normal/low-normal genotype was the most frequent, followed by low-normal/normal and normal/normal. A comparison of ovarian reserve markers and reproductive outcomes of the three most frequent genotypes revealed that AFC in the low-normal/normal genotype was significantly lower than the low-normal/low-normal genotype. The low number of CGG repeats affected AMH levels and AFC but not IVF outcomes per cycle of treatment.