In response to the doctor - there are many women who have babies and then their bodies change and can no longer naturally carry a baby to term by themselves. How old are you may I ask? Anything under 35 generally means that they will make you waste your years, emotional and physical strength until running some pretty simple tests. Unfortunately we have a reactive medical approach in Australia instead of a proactive one. Costs the government a lot more to treat things reactively. I'm a firm believer in pre-pregnancy blood screening as an option.
I was able to get some bloods done after our second loss but unfortunately the doctor didn't include all the tests as many are unknown due to their currency in the medical profession.
And then again at the end of the day...the miscarriages could have just been an unfortunate happening as the baby developed. It's nice to rule out anything obvious though.