I was reading an interesting article about developing super early testing using EPF (Early Pregnancy Factor), which is released within hours of fertilisation and starts to lower the woman's immune response so that she doesn't reject the developing blastocyst. I fear though that the incidences of chemical pregnancies would shoot up. I can't remember the statistic now, but there are a lot more fertilised eggs than successful pregnancies. Lots of issues come at implantation stage or in those early few days when chromosomal abnormalities prevent proper development of the blastocyst. These pregnancies are never picked up by hCG tests as they are over by then, but if you could test using EPF then so many more women would experience chemical pregnancies. It would be amazing to know the day after ovulation, but so so horrible to have false hope every cycle if you had those very early losses frequently.
Another interesting article I read recently was about urine tests that can determine the risk of miscarriage... something to do with proteins I believe. Not sure I'd want that either!! Imagine all the false results and the stress that would cause!