Study: Effects of cancer diagnosis and treatment during pregnancy on the health and development of the child

IN DEPTH REVIEW OF RESEARCH

Study background:

Research on how cancer diagnosis in a pregnant woman and any subsequent chemotherapy and/or radiation therapy affect the fetus and its development after birth has been limited. Dr. Frédéric Amant of the University Hospitals, Leuven, Belgium and colleagues from the International Network on Cancer, Infertility, and Pregnancy collaborated on this multicenter international study of children born to mothers who were diagnosed with cancer during their pregnancy. The study was published in The New England Journal of Medicine in November.

Researchers of this study wanted to know:

Are there developmental effects in babies born to mothers who were diagnosed with cancer during their pregnancy?

Population(s) looked at in the study:

The researchers compared 129 children born to mothers diagnosed with cancer during their pregnancy to 129 children of mothers who did not have cancer while pregnant. The children from mothers without cancer were the same gestational age (born at the same number of weeks) as the children born to mothers diagnosed with cancer. Mothers with all types of cancers were included in this study, but notably more than half the women in the study had breast cancer during pregnancy.

The mothers in the study who had cancer had the following treatments:

• 13 had surgery
• 41 had chemotherapy
• 1 had radiation therapy
• 48 had surgery and chemotherapy
• 3 had surgery and radiation therapy
• 3 had chemotherapy and radiation therapy
• 4 had surgery, chemotherapy, and radiotherapy
• 1 had Herceptin, a targeted therapy for HER2+ breast cancer
• 1 had Interferon β, an immune therapy

14 had no treatment while pregnant

Study findings: 

1. About 61% of the children whose mothers were diagnosed with cancer while pregnant were born before their due date. However, most were less than 2 weeks early, meaning the babies were close to full term.
2. Medical issues and surgical needs were similar between the children whose mothers were diagnosed with cancer and those who were not.
3. No overall difference was found in cognitive development at 18 months or 3 years between the children of mothers diagnosed with cancer and the children with mothers who did not have cancer.
   • Researchers also looked at children of mothers who had chemotherapy while pregnant; they also found no differences in cognitive development between them and the children of mothers who did not have cancer.  
4. Three-year-olds whose mothers were diagnosed with cancer while pregnant with them had no differences in heart rate, blood pressure, or other indicators of heart health when compared with three year olds of mothers who did not have cancer while pregnant.

Limitations:

While promising, this study has several limitations. 

• The authors note that age 3 may be too soon to see heart, cognitive, or other problems that may develop in the future. 
• These results may not apply equally to all chemotherapy treatments—researchers did not look at separate chemotherapy treatments; rather, they combined all types of chemotherapy treatments into one analysis.
• Few women in the study received radiation, so it is difficult to make conclusions about this form of treatment.
• Because women were treated at different points of their pregnancy, conclusions cannot be drawn about the timing of treatment during pregnancy.
• The study did not include newer “targeted” therapies, so no conclusions can be made about these types of treatments.

Because the prenatal exposure group contained children who were born to mothers with very different treatments (including those who had no treatment), it was not possible to determine whether the cancer itself or the cancer treatment affects the developing child.

Conclusions:

The researchers were quoted in some reports saying that they plan to expand this study to add more participants, and follow them until age 18 to see what effects prenatal exposure to cancer may cause as they grow older. This is an important follow-up because this current study is relatively small and has no data on children older than 3 years.

In an editorial in the The New England Journal of Medicine that accompanied the article, Drs. Michael Greene and Dan Longo of the Department of Obstetrics and Gynecology at the Massachusetts General Hospital suggested that it is still prudent to avoid cancer treatment in the first trimester of pregnancy.  More work needs to be done to understand individual contributions of the cancer itself or different treatments that might affect a developing fetus to help women who are diagnosed during pregnancy make informed decisions.

Posted 12/08/15