Here are the steps:
1. Click Search for a case
2. Click the Clear button
3. Check the Primary Names Only
4. Enter O for the status to only search for Open Cases.
5. Click the Right arrow at the lower right corner and select Has Email
6. Click the Search By and change it from Last Name to Birth Month
7. Enter 1 for Jan, 2 for Feb, etc.
8 Click Search
9. At the Found Cases window click the Export button (second button at the lower left)
10. Click Email to Clipboard
In your Email program, type Ctrl-V to Paste all the Emails. It's strongly recommended to send the Email to yourself and Paste the Emails into the Blind Copy section for privacy.