- Women who are currently pregnant will be excluded from the study. Women who became pregnant by In Vitro Fertilization IVF or any hormonal manipulation (i.e. fertility drugs such as clomid ®) are also excluded, as they may have an altered pre-pregnant hormonal state. All women will have a urine pregnancy test performed at each of the two study visits and must not be pregnant in order to continue in the study. Subjects are not allowed to donate blood between study visits.