She has assisted at over 1,000 births and is currently teaching in the nurse-midwifery program at the University of Minnesota.
Women produce varying levels of hCG despite similar gestational ages.
It is not always a given that the embryo implanted precisely at 14 days after the first day of the last menses. Fertilized ovums have been known to drift in the uterine environment for days before implanting. This would affect hCG levels and timing of positive tests. According to manufacturers, all tests will detect pregnancy in 100 percent of pregnant women within 42 days after the last menstrual period. Test kits are not required to provide data showing the sensitivity and specificity of their product, so it can be difficult to make informed choices between products on the pharmacy shelf.