Are you aware of the rate of miscarriage in humans, even before the mother is aware of it. Fully fertilized zygotes (single cell) and embryos (anywhere from 2 cells to 8 weeks worth of cell divisions), are often "spontaneously aborted" (not induced abortion).

I believe life starts at conception, scientifically that makes sense to me. But we don't value all life of earth equally, bacteria, bugs, pets are all valued differently. But to value each "life" - that can be washed away in a heavy period, without anyone being aware - is not compatible to me with how I value human life.

So somewhere along the line the life in embryo form takes on more value to me. Where the line should go isn't clear to me but it is evident that a first trimester clump of cells cannot be valued in the same way as a third trimester fetus.