Gestational diabetes mellitus (GDM), defined as hyperglycemia with blood glucose values above normal but below those diagnostic of DM, and iron deficiency (ID) with or without anemia (IDA) are common during pregnancy. Both disease patterns are associated with an increased risk of complications during pregnancy and at delivery and may have a variety of negative effects on different aspects of child development. Thus, GDM and ID/IDA during pregnancy should be prevented.

Whether iron supplementation with high oral doses acutely increases hepcidin during pregnancy, and whether this acute iron-induced increase in hepcidin decreases insulin sensitivity, is uncertain.

Inclusion Criteria:

• week of pregnancy 24-28
• pre-pregnancy BMI <27.5kg/m2
• singleton pregnancy
• Hb > 8.0 g/dl

Willing to either:

• not take any iron supplements for 14 days (however, participants will receive a similar amount of total iron during the 4 study days that they would normally receive over 14 days) OR
• to take the multivitamin "Burgerstein Schwangerschaft and Stillzeit" supplements over the 14 days (contains 30 mg iron)

Exclusion Criteria:

• iron infusion within the past 6 months
• severely anemic Hb<8.0g/dl
• acute or chronic disease
• long-term medication
• medical problems known to affect iron homeostasis
• smoking

pregnancy