What role does IgG play in fertility?

The role of IgG (immunoglobulin G) in fertility is often discussed in the context of immune reactions against sperm or egg cells. Scientific literature suggests that anti-sperm antibodies (mainly IgG) can be detected in some couples with unexplained infertility. However, clinical relevance is debated: study results are heterogeneous, and many tests show high false-positive rates. Antiphospholipid antibodies (IgG) are also linked to recurrent pregnancy loss, but effect sizes are small and evidence for routine screening is weak. Commercial IgG tests for fertility (e.g., from saliva or stool) are not scientifically validated and are not recommended by professional societies. MyBody-X tests focus on nutrient deficiencies, hormones, and microbiome – not on specific IgG fertility markers. Anyone with genuine fertility concerns should seek specialized reproductive medicine evaluation, not a home test. The evidence for IgG as a standalone fertility marker is weak and inconsistent.