Failed cycle - immunological response?

Hi ladies,

Brief background story:

• I am 30 yo, doing IVF since I had both Fallopian tubes removed 8 y ago
• No other underlying issues so far (blood tests, no clotting disorders, cariotype normal)
• Generally, I have healthy lifestyle, don’t smoke and barely ever drink
• I do have extremely painful periods, but none of my doctors thought I had endometriosis nor advised to do additional examinations 
• We did 1 IVF round, obtaining 2 embryos (grading 5AA & 3AA)
• Didn’t do genetic testing as the doctor said it’s highly unlikely both will have chromosome abnormalities
• 5AA transfer ended up in BFN
• 3AA ended up being chemical pregnancy (Beta 1=31, Beta2=38)

We have decided to try with the round 2 and the only additional test the doctor is suggesting is DNA sperm fragmentation for my partner (he has 2 kids from the previous marriage).

The doctor really chalks up the failure to “you really have bad luck and you need to try again”

However due to emotional, mental and financial cost, I would like to discard any alternative explanation (such as my immunological response). The doctor says it’s unethical to take that step at the moment as it is invasive procedure usually done after 3 failed transfers.

Does anyone have similar experience or any advice to offer from medical point of view?

Much appreciated!