Cancer during pregnancy is thankfully not common, only occurring in one in approximately every 1,000 cases. Importantly, a pregnant woman with cancer is still capable of giving birth to a healthy child, although some cancers can spread to the foetus via the placenta.
Cancer symptoms and diagnosis
Some cancer symptoms can go unnoticed as they are common during pregnancy; abdominal bloating, headaches or rectal bleeding for example. Sometimes, a pregnancy can actually reveal cancer that has previously gone undetected; a Pap test for cervical cancer for example. Ultrasound performed during pregnancy can spot ovarian cancer that might have otherwise not been detected.
The most common cancer to occur in pregnant women is breast cancer, affecting around one in 3000 pregnancies. If cancer is suspected, women and their GPs are often worried about the effects of diagnostic tests such as X-rays, although research shows that the level of radiation used is too low to damage the foetus. Other forms of gynaecological cancer screening such as CT scans, and MRI scans are also deemed safe to use.
Cancer treatment during a pregnancy
The doctor will consider the best treatment options for both mother and baby. The type of treatment recommended will depend on various factors; the gestational stage of the foetus, the type and location of the cancer, how developed it is and the wishes of the mother and her family.
Because the risk of harm to the baby is highest during the first trimester, treatment is usually delayed until after this time. If the cancer is diagnosed late in the pregnancy, doctors may decide to wait until after the birth to begin treatment, or in some cases may induce labour early.
Types of treatment and inherent risks
Surgical removal of the tumour and surrounding tissue poses little risk to the developing baby and is therefore the safest option for treatment during pregnancy.
Chemotherapy uses drugs to destroy cancer cells. This form of treatment can harm the baby, especially during the first trimester of pregnancy while the organs are still developing and in some cases can cause miscarriage. Some types of chemotherapy can be given relatively safely during the remainder of the pregnancy, although the mother may suffer from side effects which could result in early labour and low birth weight.
Radiation therapy entails using high energy x-rays to destroy cancer cells. Radiation therapy can harm the foetus so doctors avoid using this treatment wherever possible.
Cancer cells cannot pass to the baby through breast milk but doctors still advise women who are undergoing cancer treatment not to breastfeed. Chemotherapy treatment can be very dangerous, as some of the drugs may be passed to the baby in the mother’s milk.
Pregnancy and recovery from cancer
There is little difference between the chances of recovery for a pregnant woman and other women of the same age with the same stage and type of cancer. However, if diagnosis or treatment is late because of her pregnancy, she may have a worse prognosis. In addition, the amount and type of hormones produced during pregnancy can affect the growth and spread of some kinds of cancer.