Ob/Gyn Practice Today
Pregnancy Is Safe for Cancer Survivors -- and Their Babies
Although most cancer survivors can be given the go-ahead to get pregnant, there are some things they should probably be warned about ahead of time.
Research suggests that although there is only a minimal risk of pregnancy complications among cancer survivors, a subgroup of women who have had previous radiation therapy, particularly to the pelvis, should probably be regarded as high risk, suggests Dr. Daniel Green, Professor of Pediatrics at the University at Buffalo School of Medicine and Biomedical Sciences, State University of New York, and a pediatric oncologist and hematologist at Roswell Park Cancer Institute in Buffalo, who is principal author of a study on pregnancy outcomes among participants in the Childhood Cancer Survivor Study.
"In this group, there's pretty good evidence of a substantial risk for either a premature or low-birth-weight baby," he said, explaining that the mechanism is likely radiation damage to the uterine lining, inhibition of growth of the bony pelvis, and hypoplasia of the uterine arteries.
Dr. Green's study of 1915 female cancer survivors and their 4029 pregnancies (63% live births, 1% stillbirths, 15% miscarriages, 17% abortions, 3% unknown or in gestation), found that infants of patients who received pelvic irradiation were more likely to weigh < 2500 g at birth (RR = 1.84, P = .03). It did not identify adverse pregnancy outcomes for female survivors treated with most chemotherapeutic agents.
Dr. Elyce Cardonick, Assistant Professor of Obstetrics and Gynecology at Thomas Jefferson University in Philadelphia, Pennsylvania, has reported similar findings.
Her study, which she presented at the most recent meeting of the American College of Obstetricians and Gynecologists, followed 49 cancer survivors prospectively through their subsequent 63 pregnancies. Of the 66 children born (there were 3 sets of twins) over a 6-year period, the rate of major malformations was 1.5% (1 child with an omphalocele), and the rate of fetal growth restriction was 1.5%.
The mean birth weight was 3200 g, the mean gestational age at delivery was 38 weeks, and 47.5% of the pregnancies were delivered vaginally. In general, babies born to mothers who had been exposed to radiation therapy weighed 400 g less than average, and 5 of the 8 preterm deliveries were to mothers who had received radiation therapy, she said.
There was no noticeable effect of prior chemotherapy exposure.
"It appears that several placental abnormalities -- including accreta, preterm delivery, and low birth weight, may be increased in radiation patients.
With all the healing that your body has to go through after radiation therapy, there may be some change in the vasculature, or some fibrosis, which may damage the way the cytotrophoblasts invade into the uterus and create normal vasculature for a healthy pregnancy," said Dr. Cardonick, who is also Director of the Cancer and Childbirth Registry in Philadelphia.
Two mothers with prior radiation exposure had complications. One with prior thoracic radiation complained of persistent shortness of breath and was found to have significant mitral regurgitation.
The other, who had prior thoracic/abdominal radiation, presented with congestive heart failure, aortic regurgitation, intrauterine growth restriction, and severe preeclampsia at 25.5 weeks.
Although neither study found increased risks associated with chemotherapy exposure, the chemotherapy agent doxorubicin can cause damage to heart muscle, and patients who have been treated with this drug do have a small risk of developing congestive heart failure, says Dr. Green.
"In patients who have this history, a cardiologist can assess their cardiac function before pregnancy -- if it's normal it doesn't absolutely guarantee something won't happen later on, and if it's abnormal, that doesn't necessarily mean they shouldn't get pregnant," he said.
There were 2 cancer recurrences among Dr. Cardonick's cohort, 1 in a breast cancer patient at 30 weeks of pregnancy, and the other in a melanoma patient after 2 pregnancies. She says her results should reassure patients, and their physicians, many of whom may be unnecessarily cautious.
"Studies show that less than 57% of cancer survivors are given any information about future pregnancy, and there is a high rate of elective terminations in this group, probably because of misinformation about the dangers of pregnancy and the risks to the fetus," she said.
"Overall, even patients with prior radiation therapy should not be discouraged from having pregnancies, but [they] need to be watched closely. In general, the pregnancy outcomes are good for both mothers and babies."
Green DM, Whitton JA, Stovall M, et al. Pregnancy outcome of female survivors of childhood cancer: a report from the Childhood Cancer Survivor Study. Am J Obstet Gynecol. 2002;187:1070-1080.
Kate Johnson is a medical journalist living in Montreal, Quebec.
Disclosure: Kate Johnson has no significant financial interests to disclose.
Medscape Ob/Gyn & Women's Health 8(2), 2003.
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