Phobias only become problematic when they start interfering with your daily life. For example, my mom is afraid of snakes, and at one point she refused to go outside because there might be a snake. When she had to go outside to go somewhere, she would run all the way to the car to minimise the chance of seeing a snake. At this point it seems like you're just disturbed by the concept of pregnancy, though I could be wrong.
And I'm bothered by pregnancy too. I hate it when people around me talk about it. My mom loves art of pregnant women, which is so, so disturbing to me. The idea of me being pregnant is even worse, I'd probably cut out the little parasite myself if I was. There shall be no sperm making contact with my girly bits, ever.
Plus, I'm essentially pro-abortion. Humans are overpopulated, there are plenty of children waiting for adoption anyway, the desire to have your own children is entirely evolutionarily based and a bit outdated, as such, strain on resources, etc. And pregnant women are frighteningly emotional.