Teratoma is a common benign ovarian tumor in women, and most teratomas do not affect the fetus. Since the majority of teratomas are smaller than 5cm, even under the stimulation of pregnancy, teratomas generally do not grow significantly large, and it is generally considered that small teratomas do not affect the fetus. However, if the teratoma is very large, more than 8cm, there is a risk of rupture and infection during pregnancy, which could potentially affect the fetus. For large teratomas during pregnancy, enhanced monitoring is necessary to avoid rupture and infection, in order to protect the fetus.