- Individuals who are pregnant or lactating. As part of their routine preoperative testing, all women of child bearing age receive a pregnancy test. The research staff will follow up on these results in order to determine eligibility. Women who have had a hysterectomy or have not had menses for > 24 months will not be required to undergo a pregnancy test. Pregnant women are excluded from this study because there is unknown risk associated with Ferumoxytol (US FDA Risk Category C: there are no controlled studies in women, or no studies are available in either animals or women). Because there is an unknown but potential risk of adverse events in nursing infants secondary to treatment of the mother, breastfeeding women will be excluded from this study