As I understand it-at least 6 and up to 10 pregnancies is remarkable, on a carrier even, though Ive heard high numbers on smaller ships. This indicates a real problem-especially considering the enormous expenses to the taxpayer, and burden on the military that didn't exist before.
And the initial prego check at 2 weeks is because it establishes a baseline that the woman is not prego on departure. There are more sensitive and specific tests, but they are more expensive. Im not denying stuff happens, Im saying THIS STUFF happens.