Evidence check: IgG in the context of fertility

The provided context does not address IgG in the context of fertility. IgG antibodies are part of the adaptive immune system and have been studied in fertility disorders, such as antisperm antibodies (ASA) or immune responses to infections (e.g., Chlamydia trachomatis). However, the evidence for a causal role is weak: some studies report elevated IgG titers in unexplained infertility, but test sensitivity and specificity are low, and major guidelines (e.g., ESHRE) do not recommend routine IgG screening. MyBody-X does not appear to offer IgG-based fertility tests based on the given context. The evidence level for IgG testing in fertility is therefore 'unclear' – it is a mechanistic biomarker without strong clinical validation. Caveat: a positive IgG result alone does not justify specific treatment; a full reproductive workup is necessary.