No.
1. Not every woman who commits adultery gets pregnant thereby. But the context shows it is a trial that any man who suspects his wife of unfaithfulness can cause her to undergo–there is nothing saying or suggesting she must be pregnant. This was a trial before God to reveal the unknown, with death as the result for the guilty woman. If it were to only work if the woman was pregnant, the whole point would seem to be wasted: wouldn't a pregnancy at an odd time rather make adultery more obvious instead of less? It's precisely the adulteries that don't result in pregnancy that would most need a trial like the one described.
2. Some translations say "make your womb miscarry" but the majority and the more literal and common reading, as exemplified in KJV, is "make thy belly to swell, and thy thigh to rot".
3. Maimonides interprets the passage literally, as in, the woman would die through the bursting of her entrails. He cites more ancient Jewish sources saying the same thing.
Overall, the point of the trial may have been less to cause the woman's death than, through the fear and spectacle, to get her to confess to any hidden adultery.