Can xolair affect menstrual cycle?

Short answer: There isn’t a known, common link between Xolair (omalizumab) and menstrual cycle changes.

What to consider:
- Menstrual irregularities are not listed as a common side effect of omalizumab in its official labeling.
- If you’ve started Xolair and notice changes to your period (irregular cycles, very heavy bleeding, missed periods, or other new symptoms), it’s reasonable to discuss with your healthcare provider. Many factors can affect the cycle (stress, weight changes, other medications, thyroid issues, pregnancy, etc.).

What to do:
- Track your cycle and any other new symptoms.
- Talk to the clinician who prescribed Xolair if you’re concerned, especially if you might be pregnant or planning pregnancy, or if the changes are bothersome or persistent.
- If you suspect pregnancy or have unusual bleeding, seek medical advice promptly.

If you’d like, tell me more about what you’re experiencing (cycle length, symptoms, timing relative to injections), and I can help you think through possible next steps.