Pregnancy and Periods

Hi to everyone,

Can anybody help?

I am on Tamoxifen and have zelodox implants every 28 days.

I haven’t had a period since October when I was still receiving chemo.

I started the Tamoxifen and zelodox in November, as I haven’t had a period and led to believe that virtually impossible to get pregnant whilst on zelodox why then do the health professionals insist that you should use alternative contraception ie - condoms if the chance of getting pregnant is so slim?

Would be glad if anybody could help?

Many thanks