All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
One of the noble objectives of the Islamic Law is to protect the society from adultery and fornication and preserve the honour and dignity of the people. That's why punishment has been legislated and conditions, or say restrictions, have been put in place so that the people do not accuse each other without evidence. So adultery can only be confirmed by the following two matters: The existence of four witnesses, or the confession by the person who committed the sin. If there are no witnesses nor a confession, then there is no punishment. Becoming pregnant is not enough evidence by itself to apply the punishment on the woman according to the majority of the scholars. Because a woman could be raped or that a person might have had sexual intercourse with her while she was asleep. It might also be that pregnancy could take place for a reason other than sexual relationship, like entering the sperm (into the womb) by another means. As regards raping a woman it does not necessitate punishment on the man except if he admits it himself or is proven with four witnesses. The woman cannot be punished as well if she claims that she was raped. So it is not correct as you mentioned in your question to say that the woman is wronged. Lastly, it should be noted that a Muslim should be certain that Allaah's Legislation is just, and then he can ask about whatever difficulties he might find (regarding religious matters).
Allaah knows best.