Why are pregnant women tested at 16 weeks for HIV when the window period for HIV is 6 months? Do most cases show up within the 16 weeks? I am slightly worried as I have just found out that there is a risk that the sperm I used to conceive my daughter could have been contaminated and am extremely worried. My daughter is a big healthy baby though but I have just finished an 11 month stint of breast feeding. Serious answers please.

i thought i should add that i did have the 16 week HIV test and it was clear.