Study finds few adverse effects for babies exposed to chemo in pregnancy


By Michael Woodhead

12 Sep 2019

An Australian study has provided reassuring findings for mothers and babies on the effects of exposure to chemotherapy during pregnancy.

A prospective cohort study identified 18 babies of women with breast cancer who were exposed to chemotherapy in utero during the first or second trimester of pregnancy.

While most of the babies were purposely delivered preterm, there were no congenital abnormalities or stillbirths among the infants who were exposed to at least two different chemotherapy agents.

The study, led by researchers at UTS and the Kids Cancer Centre, Sydney Children’s Hospital,  found a significantly higher rate of preterm births among babies exposed to systemic chemotherapy during pregnancy compared to a matched cohort of nonexposed babies (12 out of 18 vs 0 out of 6).

The mean gestational age at birth for the 18 chemotherapy exposed babies was 35.7 weeks, significantly lower than that for the six non-exposed babies (mean 38.8 weeks).

All the babies were exposed to alkylating agents such as cyclophosphamide or platinum compounds such as carboplatin. Most (89%) were exposed to anthracyclines such as doxorubicin and more than half (56%) to taxanes.

The median gestational age at first in utero exposure was 20 weeks (range 13–31). Fourteen (78%) of the 18 babies had their first exposure to chemotherapy in the second trimester and four (22%) in the third trimester. The mean duration of exposure was 10.4 ± 5.8 weeks.

The perinatal outcomes were good, with no stillbirths, diagnosed congenital malformations or neonatal deaths in any of the babies exposed to chemotherapy in utero. Resuscitation was needed in two babies exposed to tamoxifen combined systemic therapy, born at 34 and 36 weeks respectively. Mild respiratory distress was seen in one baby n=born at 36 week.

The study investigators said it was notable that the two babies exposed to tamoxifen  – which is contraindicated in pregnancy – were born without congenital malformations. Similarly, the ten babies exposed to taxanes had  perinatal outcomes similar to other babies.

While the number of chemotherapy exposed babies in the study was low, the findings provided some assurance about the impact of in utero exposure, they concluded. The main effects were preterm birth in the chemotherapy-exposed babies, which was iatrogenic to facilitate maternal systemic chemotherapy postpartum.

“Our findings show that breast cancer diagnosed during mid-pregnancy is often treated with chemotherapy,” they commented.

“The gestation at diagnosis influenced the decision on the timing of chemotherapy and the non-use of radiotherapy during pregnancy.”

The findings confirmed other reports suggesting little risk from exposure to anthracyclines after the first trimester, but there is a need for an international database of information on the maternal-foetal exposure and outcomes of chemotherapy and other systemic anticancer agents use in pregnancy, they suggested.

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