A woman’s ovaries are responsible for not only providing the seed for human reproduction – the egg – but also for producing female hormones that maintain female characteristics and pregnancy. There are also times when the ovaries can persist in their work with disease, such as when an ovarian cyst is combined with a pregnancy. It’s trickier to deal with and needs to require consideration of both the pregnant woman and the fetus. So, women who are planning to get pregnant are advised to do a thorough checkup before getting pregnant. The coexistence of ovarian tumors with pregnancy is not uncommon, occurring about once in every 100 to 8,000 pregnancies, and the vast majority of these are benign tumors, accounting for 95 to 98 percent of cases. It is taken seriously because the management is confusing and concerns both the mother and the child. Benign ovarian tumors in pregnancy are most common in mature cystic teratomas and plasma (or mucinous) cystadenomas. It can be said that the ovarian ovulation process, which controls a woman’s monthly menstruation, is one of the culprits that destroys the ovaries, and pregnancy is one of the best protections for the ovaries. During the months of pregnancy, the ovaries stop ovulating and recuperate. Thus, the process of pregnancy not only reproduces offspring, but is also a natural enemy of ovarian tumors, but preventing cancer through pregnancy is obviously absurd. Conversely, ovarian tumors are also enemies of pregnancy and can affect pregnancy in early, middle and late stages of pregnancy. In early pregnancy, the tumor may be embedded in the pelvis, making the uterine position abnormal, or stimulating uterine contraction, thus inducing spontaneous abortion; in middle pregnancy, the uterus increases in size, and the active ovarian tumors are prone to tip-twisting, and the severe abdominal pain and the resulting surgical operation required after the torsion can also cause miscarriage or preterm labor; in late pregnancy, if the tumor is large and squeezes the uterus, then it may cause the abnormal position of fetus, so that the head of the fetus can’t enter into the In late pregnancy, if the tumor is large and squeezes the uterus, it may cause abnormal fetal position, preventing the fetal head from entering the pelvis; if the tumor is in a low position, it may block the birth canal, causing obstructed labor. Physiological changes of the body during pregnancy can also affect the ovarian tumor and develop towards an unfavorable situation. Pelvic congestion during pregnancy increases the blood supply to the ovary, and the tumor may grow rapidly; during pregnancy, the increase of uterine volume and the change of position may cause the ovarian tumor to tilt; and the extrusion during delivery may cause the tumor to rupture. Moreover, the enlargement of uterus during pregnancy often makes ovarian tumors not easy to be detected and delays the diagnosis and treatment of tumors. Thus, there is often a dilemma when dealing with pregnancy and cancerous tumors. They hope that the pregnancy will be successful, but also hope that the treatment of the tumor will not be delayed: does the pregnancy need to be terminated? Will continuing the pregnancy to the viable fetal stage affect the prognosis of the tumor? How will the tumor affect the fetus? What harm will treating the tumor cause to the fetus? Likelihood of future pregnancies after termination of this pregnancy? When is the best time to operate? etc. It is necessary for doctors to consult with patients and their families to weigh the pros and cons and decide the treatment plan. First of all, we should pay attention to the pelvic mass found during pregnancy and not delay the diagnosis of malignant tumors. Specific principles: ① For ovarian masses combined with pregnancy, if the diameter is less than 5 cm and gradually shrinks on examination, it can be considered a physiological cyst and does not need to be dealt with; if the history and examination are highly suspicious of endometriosis cysts, they can also be left untreated, especially in elderly patients who have difficulty in getting pregnant, because the large amount of progesterone secreted during pregnancy will inhibit its growth; ② If the diameter of the mass exceeds 5 cm then laparoscopic surgery or cesarean section should be performed around 16 weeks of pregnancy, regardless of whether there are complications such as torsion. Only by performing surgery at the right time can complications be avoided and malignancy detected in time. It is generally accepted that surgery in the middle of pregnancy has a reduced chance of inducing miscarriage relative to early pregnancy, and anesthesia drugs, etc., have less impact on fetal development; ③ If the mass is hard, nodular, fixed, or bilateral, and especially if it cannot be excepted as malignant, cesarean section should be performed regardless of gestational age. Immediate surgery is also required if complicated by tumor torsion, rupture or infection, or if accompanied by acute abdominal pain, nausea and vomiting, or even shock. Secondly, if it is decided to operate during pregnancy, comprehensive exploration of the pelvic and abdominal cavities is needed during the operation, and the resected mass should be initially judged as malignant by the naked eye and sent to frozen section for rapid pathology to determine the benignness or malignancy of the tumor, and it is a matter for doctors to comprehensively explore and excise the suspicious tissues and send them to rapid pathology to determine the initial diagnosis and histological category, which is not recounted too much. Finally, for women who plan to become pregnant, a thorough preconception examination is necessary. The program includes at least a pelvic ultrasound and, if necessary, a blood test for tumor epitopes (specific substances whose concentration in the blood is elevated in the presence of a tumor, e.g., CA125, CA199, CEA, AFP, etc.). Generally speaking, if you are not pregnant, ovarian cysts with a diameter of more than 5 centimeters need to be treated. However, for women who are planning to become pregnant, the criteria are slightly stricter, tentatively set at 4 centimeters, and even if the contents of the mass are fluid (called a cyst), surgery should be performed, with laparoscopic minimally invasive surgery being the best. However, even if the swelling is less than 4 cm in diameter, but has a solid component that does not go away with repeated examinations, it should be treated before pregnancy to avoid the danger of the tumor growing after pregnancy. In conclusion, it is the best policy to check and rule out ovarian tumors before pregnancy, to defuse the time bomb, and to safely and happily go through the pregnancy period.