I'm so sorry for your losses. In my experience, you have to have had 3 MC's in a row with the same partner before you will be offered any tests. You're not guaranteed to get any answers even after the tests though. I'm currently on my 4th pregnancy (5 weeks gone) after 3 consequtive MC's (5w, 7w, MMC) and all our tests came back with nothing. The doctors have told us that all we can do is put them down to bad luck and just keep trying.
Might be worth getting tested for coeliac which can be associated with miscarriage. It wasn't even thought of when I had a mc several years ago, but I was diagnosed with this just over a year ago. I don't know if that is one of the things they automatically test for now but I suspect not. I also have 2 dc's with the mc between them. DD (oldest) was prem. Coeliac can cause both prem birth and miscarriage.
You may well be sent for some investigations, all will be blood tests.
I had 2mcs, (all under 9 weeks) had ds (now aged 8) In last 4 years have had another 3 mcs.
Am currently about 5 weeks pregnant, ttc for 18 months since my last mc.
I asked tobe referred to the nearest fertility centre whichfor me is Liverpool. They took shed loads of blood. I went back for results....all normal. No wiser about why i cannot carry a pregnancy to term. I think ds was a small miracle.