Speaking as a transmasculine person, you can still get physically pregnant while on testosterone if you haven't had bottom surgery (which is why birth control is still important if that's relevant to your activities). If you do end up physically pregnant, you'll have to stop taking testosterone for the duration of the pregnancy.
Spiritual pregnancy is something anyone can go through if that is your belief, but it will not produce a physical being. At that point, it's up to you to go through if that's what you want in your spiritual journey. It's not really a subject that's brought up much, so not many people have exposure to it, let alone opinions on it.
I've spoken with people who claim to have fallen in love with a spirit or spiritual being and having a family on the astral plane. I have no clue if/how that works, but people claimed it was all astral, not physical. So, I suppose if you somehow became pregnant on an astral/spiritual level, it would be similar to phantom pains people report when they lose a limb? This is just theory, I don't know if/how it's possible. I just remember talking to people in the past who claim on the astral they had a spiritual family [two with spirits, one with a demon and one claimed they had a twin brother reborn as a spirit Dragon, so on the astral, they were a Dragon] Sorry I can't explain better, I've just heard stories so it's possible, just not physical pregnancy. [you won't give birth to a spirit or physically show you're pregnant]