I’m also wondering what you mean by trying to get pregnant 6 times.
The overall statistics on fertility is that if 100 couples are having sex on average twice a week without using any birth control, 80 of them will have gotten pregnant by the end of the first year. Another 10 out of the remaining 20 will be pregnant by the ned of the second year. At that point, the last 10 couples have fertility issues. If they go on to have a full fertility workup, about ⅓ will have female related infertility, ⅓ male factor, and the last ⅓ still unknown, with nothing definitive turning up.
In RL, I’m a GYN nurse practitioner, and if a couple is actively trying to get pregnant, we usually suggest giving it 2 years before starting testing if the woman is in her 20s, 1 year if she’s 30–35, and 6 months if she’s 35 or older.
Infertilty testing can get very expensive and invasive pretty quickly, and most health insurance policies won’t cover any of it. There are some first steps that are pretty reasonable and can yield quite a bit of information – your GYN care provider can tell you more.