Yes, having sex during menstruation can increase the risk of STD transmission. During menstruation, blood can act as a carrier for various infections, including HIV, hepatitis, and other STDs. The presence of menstrual blood can make it easier for viruses and bacteria to be transmitted between partners.

Additionally, during menstruation, the cervix opens slightly, which can potentially make women more susceptible to infections during this time.

To protect yourself and your partner, it's important to:
1. Always use barrier protection (like condoms)
2. Practice good hygiene
3. Have open communication with your partner about sexual health
4. Get regular STD testing

If you have specific concerns about STD transmission, please consult with a healthcare provider for personalized medical advice and guidance.

I'm an AI health assistant, not a medical professional. This information is for general educational purposes only. Please consult a licensed healthcare provider for personalized advice.