Does cancer itself affect the fetus during pregnancy?

In general, cancer itself rarely affects the fetus during pregnancy [2]. Cancer cells do not typically cross the placenta to reach the fetus. However, there are very exceptional cases where cancer can indirectly affect the pregnancy or the mother's health, which may require medical interventions that could have potential impacts. It is important to know that tumors occurring during pregnancy can be benign (non-cancerous) or malignant (cancerous) [2].

Common Types of Cancer During Pregnancy and Their Potential Effects

Some types of cancer are considered more common during pregnancy, including breast cancer, thyroid cancer, cervical cancer, lymphoma, and melanoma [2]. In most cases, the presence of these tumors does not directly affect the fetus's growth or health. However, some rare cases may lead to complications:

• Cervical cancer: If the cancer is slow-growing and in its early stages (Stage I) and diagnosed in the first trimester, the care team may suggest delaying treatment until later in the pregnancy or after delivery. If it is fast-growing or has spread beyond the cervix, it may require immediate treatment [3].
• Gestational Trophoblastic Disease (GTD): This is a special type of tumor that occurs when a fertilized egg does not develop into a fetus. It is often benign, but some types can be malignant [2]. Its symptoms may resemble those of a normal pregnancy in its early stages, and it is important to see a doctor if abnormal vaginal bleeding occurs [2].

Safe Diagnosis of Cancer During Pregnancy

When cancer is suspected during pregnancy, doctors focus on using diagnostic methods that do not harm the fetus. Safe imaging tests include ultrasound and MRI without gadolinium contrast, as these methods are generally considered safe. Biopsies (taking a tissue sample) may be used to confirm the diagnosis, with necessary precautions taken for the safety of the pregnancy.

Safe Treatment Options and Their Effects

The choice of treatment depends on the type and stage of the cancer, the stage of pregnancy, and the mother's wishes. The healthcare team works to find the best treatment plan that balances cancer treatment with fetal safety [2]. Some treatment options may be safe during certain stages of pregnancy:

• Surgery: This can be safe in some cases, especially during the second trimester.
• Chemotherapy: Considered unsafe for the fetus during the first trimester [3]. However, some types of chemotherapy can be administered in the second or third trimester and usually do not harm the fetus, though they may increase the risk of preterm birth or low birth weight [3].
• Radiation Therapy: Considered harmful to the fetus throughout its development, and pregnancy cannot be continued during this treatment [3].

In some cases, doctors may suggest early delivery (around 37 weeks) via cesarean section, especially if necessary to begin treatments that cannot be performed during pregnancy, such as radiation therapy or certain types of surgery [3]. For more information about challenges, diagnosis, and treatment, you can visit Cancer and Pregnancy: Challenges, Diagnosis, and Safe Treatment Options (Arabic).

Next Steps and Follow-up

If you are diagnosed with cancer during pregnancy, it is essential to work closely with a multidisciplinary healthcare team that includes oncologists, obstetricians, and maternal-fetal medicine specialists. They will carefully evaluate your condition and discuss all available options, keeping your health and your baby's health in mind. Do not hesitate to ask questions and express your concerns. Regular check-ups and close follow-up are necessary to ensure the best outcomes for you and your baby.

Medical references

• Tumors and Pregnancy
• Cervical Cancer Treatment during Pregnancy