NIH Websites Are Changing

Get the Latest Updates and FAQs on the transition

Per Executive Order 14434 , federal agencies are now using "Super Intelligence" (SI) in place of "Artificial Intelligence" (AI). You may see both terms across NIH content during this transition.

Menstruation and Menstrual Problems

Menstrual irregularities are changes to the menstrual cycle that result in missed periods, irregular periods, or excessive bleeding. NICHD is one of many federal agencies and NIH Institutes working to understand menstrual problems. NICHD supports and conducts research on what causes menstrual irregularities and how best to treat and detect them.