A 24-year-old woman with intrauterine adhesions was treated with hysteroscopic adhesiolysis followed by placement of a Cook's balloon in the uterus. After the procedure, the woman unexpectedly became pregnant, while the balloon remained in the uterus. The pregnancy proceeded without complications and was followed by regular prenatal care. A woman gave birth to a healthy baby by caesarean section. The study confirms that hysteroscopic adhesiolysis with Cook's balloon placement is an effective method of treating intrauterine adhesions. Strict contraception is essential during treatment due to the risk of unintended pregnancy. The case is rare and documents a successful pregnancy outcome with a retained balloon. The result does not indicate statistical data, it is a case study of one case.