Male, female survivors of childhood cancer not at risk for pregnancy complications

According to data from two retrospective cohort studies, women who survived childhood or adolescent cancers or women whose male partners survived childhood cancer are not at elevated risk for pregnancy complications, having babies born with birth defects or newborn deaths. The studies, conducted by the same group of researchers, were published in Archives of Pediatric & Adolescent Medicine.

The first study compared birth outcomes among women survivors of childhood and adolescent cancers with women who had no history of cancer and gave birth. Using cancer registries, the researchers identified 1,898 girls younger than 20 who were diagnosed with cancer from 1973 to 2000 and had live births after diagnosis. Using birth records, the researchers identified 14,278 controls. Women who survived genital tract cancers were analyzed separately.

Compared with controls, babies born to women who survived childhood cancer were more likely to be preterm (RR=1.54; 95% CI, 1.30-1.83) and to weigh less than 2,500 g (RR=1.31; 95% CI, 1.10-1.57). The RR for preterm and low birth weight were lower among survivors of genital tract carcinomas (RR=1.33; 95% CI 1.13-1.56 for preterm and RR=1.29; 95% CI, 1.10-1.53 for low birth weight).

The researchers noted their findings did not suggest germ cell mutagenicity, as evidenced by the lack of increased risk for malformations, infant death or altered sex ratio.

The results from an exploratory analysis revealed that survivors of bone cancers were at an increased risk for diabetes (RR=4.92; 95% CI, 1.60-15.13), while survivors of brain tumors and those treated only with chemotherapy had a higher risk for anemia (RR=3.05; 95% CI, 1.16-7.98 and RR=2.45; 95% CI, 1.16-5.17).

“Increased occurrence of preterm delivery and low birth weight suggest that close monitoring is warranted,” the researchers wrote. “Increased diabetes and anemia among subgroups have not been reported, suggesting areas for study.”

Reproductive outcome of male survivors

The second study, also a linked cancer-birth registry analysis, compared the risk for reproductive and infant outcomes among male survivors of childhood cancer. The study included 470 men aged younger than 20 and diagnosed with cancer between 1973 and 2000. All were fathers of live births after diagnosis. Controls (n=4,150) were matched based on year and age at fatherhood and race/ethnicity.

Infants born to cancer survivors were at borderline risk for low birth weight (<2,500 g; RR=1.43; 95% CI, 0.99-2.05). The risk was associated with younger age at diagnosis and exposure to chemotherapy (RR=1.96; 95% CI, 1.22-3.17) or radiotherapy (RR=1.95; 95% CI, 1.14-3.35). These babies were not, however, at risk for being premature, small for gestational age, having malformations or altered sex ratio.

In addition, maternal complications were not more prevalent among female partners of male survivors compared with controls. Preeclampsia was, however, associated with certain cancers like central nervous system tumors (RR=3.36; 95% CI, 1.63-6.90).

“For male survivors identified as fathers in state birth records, the vast majority of associated pregnancies resulting in live births were not at significantly greater risk of complications vs. those of comparison subjects,” the researchers wrote. “However, our finding of increased low birth weight and preeclampsia associated with some diagnostic groups raises the possibility that prior cancer therapy may affect male germ cells with effects on female partners and pregnancy of male survivors.”

Mueller BA. Arch Pediatr Adolesc Med. 2009;163:879-886.

Chow EJ. Arch Pediatr Adolesc Med. 2009;163:887-894.