Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that the Noble Prophet (peace and blessings be upon him) made them perform li'an due to the pregnancy being doubtful.
Hadith Referenceالفتح الربانی / كتاب اللعان / 7202
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«حديث صحيح، أخرجه ابن ابي شيبة: 14/ 157 ، (انظر مسند أحمد ترقيم الرسالة: 3339 ترقیم بيت الأفكار الدولية: 3339»
Brief Explanation
Benefits: … This is a reference to the incident of Hilal ibn Umayyah, when his wife performed li‘an while she was pregnant. Thus, the meaning of li‘an in the case of pregnancy is that if the husband finds the pregnancy in his wife's womb to be suspicious, then li‘an can also take place.