Answered by Shaykh Hamza Karamali, SunniPath Academy Teacher
Is pregnancy considered sufficient evidence for the enactment of the hadd punishment for adultery?
In the Name of Allah, Most Merciful and Compassionate
The Prophet (Allah bless him and give him peace) commanded us in a famous hadith to ward off the hadd punishments with doubts [shubuhat]. Many punishments prescribed by Islamic Law often seem very harsh, but people forget that these punishments are only applied when certain very stringent conditions are met.
The hadd punishment for fornication and adultery can only be enacted if there are four witnesses who witness the actual act of adultery or if someone confesses to committing adultery (there is also the case of lian, which I wont discuss right now because its not relevant). In the case of confession, if someone retracts their confession, the hadd can no longer be enacted.
It is mentioned in Bughyat al-Mustarshidin that an unmarried woman who gets pregnant and does not confess to have committed fornication [zina] does not deserve the hadd punishment, since she could have been accidentally had intercourse with [wat ul-shubha], she could have been asleep, she could have been insane (and hence not responsible for her actions) when the intercourse happened, or she could have been coerced, all of which are doubts [shubuhat] that make the hadd punishment inapplicable to her. [Bughyat al-Mustarshidin, 249]
As a note, hadd punishments are the province of the Imam of the Muslims, and are irrelevant for Muslims living in the West.
And Allah knows best.