You may be prescribed medication for your thyroid even though you do not show any symptoms. The thyroid gland provides signals to your body to produce TSH or thyroid stimulating hormones. If your thyroid production is high TSH is suppressed. If your thyroid production is low TSH is increased to boost production. Hyper- and hypothyroidism are associated with infertility.
There can be failures in IVF cycles after embryo implantation. As per our evidence and experience, the issues are rarely with sperm quality or uterine issues. The issue usually is traced to oocyte quality.
There may be chromosomal and genetic factors leading to implantation failures. The increasing age of the female partner, in the early 30s, drives chromosomal abnormalities in mature eggs increases significantly. And in the 40s, most embryos will show chromosomal abnormalities.