Introduction/Background*One in 1000 to one in 1500 pregnancies are complicated by cancer. We would like to show three cases in our institution how we discover cancer in pregnancy, although patients did not have any symptoms before pregnancy.

Methodology CASES 1: 29-year- old women, healthy women in 10 weeks gestation did Prenatal test, Livia, and they could not do analysis because they could not extract fetal blood. All her laboratory and pregnancy were in normal limit.

CASE 2: 33-year-old pregnant women in 10 weeks of gestations did Prenatal test, Veracity, and laboratory could not extract fetal blood. She was healthy with previous laparoscopic operation due endometriosis on the left side on ovaria.

CASE 3: 42-year-old pregnant women in 10 weeks of gestation did Prenatal test, NIFTY, and laboratory could not extract fetal blood. In previous history she had operation of breast cancer and hemotherapy 4 years ago.

Result(s)* CASE 1 Patient at 36 weeks of gestation patient had big palpable mass on site liver and we performed, Caesarean Section and discovered carcinoma of colon sigmoid with multiple metastasis in abdomen. The newborn was in good condition and she lived one year later.

CASE 2 Patient at 33 weeks of gestation patient had pain in her legs. Detail examination showed changes on all bones suspected on metastatic changes. We performed Caesarean Section, and we found Krukenber’s tumor with multiple metastasis in abdomen. The newborn was healthy and she lived for one month later.

CASE 3 Patient at 16 weeks of gestation patient had pain in abdomen. We did an open laparotomy and found colon cancer with meta changes in abdomen. Caesarean Section was performed in 33 weeks of gestation. Two newborns were healthy and she is alive.

Conclusion*Patients were healthy before pregnancy and Prenatal tests showed large changes in their karyotypes in terms of multiple mitoses. At the time of obtaining the results, neither the patients nor the doctors suspected they have cancer.

Our conclusion is that changes in the karyotype, as in these cases, could be the first indicator that there is cancer in the body. Could analysis of karyotype single out the risk population and be gold standard to look for cancer before the onset of symptoms?