In my experience, the potential for pregnancy is hit and miss with specific Tarot cards, and any predictions of pregnancy I make are more based on intuition than a specific card. I've predicted more than a few, but those were based more on patterns of behavior than on the Empress or other such cards coming up, though sometimes they do.
Ace of Wands often comes up in relation to fertile sex, which of course means baby-making LOL Pages, specifically the Page of Cups (the symbolism of the fish, which is a fertility symbol, in the cup, which could represent the womb). The Empress means motherhood, but I find that only somewhat reliable, and only if the person isn't already a mother. Some people are just natural mothers, and caregivers for everyone around them, and the Empress would point to that.
Mostly, it's going to be looking at the whole reading, the cards that come up, the positions, etc. to see a potential pregnancy, and even then, there's no guarantees.
