Most young female cancer survivors are at minimal risk for obstetric problems

A study based in the United Kingdom reports that, in general, most women between the ages of 15 and 39 years who have survived a cancer diagnosis are at low risk for pregnancy complications later in their lives. The study appears in The Lancet Oncology (doi:10.1016/S1470-2045(24)00269-9).

According to the study authors, limited data are available on the risks of obstetric complications among survivors of adolescent and young adult (AYA) cancer, and they noted that most earlier studies report risks only for all types of cancers combined. The purpose of this population-based cohort study—the Teenage and Young Adult Cancer Survivor Study—was to determine whether there was a negative impact on birth rates and risks of obstetric complications after treatment for one of 17 cancers in the AYA population. The authors compared the observed number of births affected to the number expected based on general population rates.

The study included more than 200,000 5-year survivors of cancer from England and Wales who were initially diagnosed between the ages of 15 and 39 years. The cohort was based on cancer registrations obtained through the Office for National Statistics and the Welsh Cancer Registry. The investigators ascertained 27 specific obstetric complications among 96,947 female survivors. They compared the observed number of affected births in the cohort with the expected number in the general population of England.

Specifically, the researchers found that between April 1, 1997 and March 31, 2022, 22,033 births occurred among 14,051 female survivors of AYA cancer from England. They also found that survivors of cervical cancer and leukemia had an increased risk for more than two specific complications from among the 27 complications investigated.

Overall, the number of births was “lower than expected” (observed-to-expected ratio, 0.68; 95% CI, 0.67–0.69). Notably, the researchers reported that survivors of genitourinary, cervical, and breast cancers reported a birth rate that was less than 50% of that in the general population.

When they focused on more common obstetric complications that were above normal, they discovered that survivors of cervical cancer were at risk of many serious pregnancy and labor complications: malpresentation of fetus, obstructed labor, amniotic fluid and membrane disorders, premature rupture of membranes, preterm birth, placental disorders (including placenta previa), and antepartum hemorrhage.

Also of particular concern were patients with leukemia, who were at greater risk of preterm delivery, obstructed labor, postpartum hemorrhage, and retained placenta. By contrast, the other cancers observed had two or fewer obstetric complications that exceeded an “observed-to-expected ratio of 1:25 or greater.” Based on their data, the researchers concluded that survivors of cervical cancer and leukemia are at risk of several serious obstetric complications: “Therefore, any pregnancy in these particular groups should be considered high-risk and would benefit from obstetrician-led antenatal care.”

In a prepared statement, the senior author of the study, Raoul Reulen, PhD, senior lecturer and National Institute for Health and Care Research fellow at the Centre for Childhood Cancer Survivor Studies at the Institute of Applied Public Health of the University of Birmingham, said that women often experience increased worry about the risk of complications during pregnancy and delivery after a cancer diagnosis, and they found that women who survived cancer are still less likely to give birth than women in the general population. “Our findings suggest that cancer survivors who didn’t have cervical cancer or leukemia can feel reassured about their risks going into pregnancy, as they do not greatly differ from the risks in the general public for the majority of obstetric complications.”

However, Dr Reulen noted, “Depending on their previous cancer type, some survivors were at a higher risk for one or two types of complications; for example, our study found survivors of kidney cancer had an increased risk of gestational hypertension.” He added, “We hope these findings can provide evidence for the development of clinical guidelines relating to counseling and surveillance of obstetrical risk for female cancer survivors.”

To ensure that cancer survivors looking to start a family receive support and assurance about managing any risks, the researchers recommend that formal guidelines be introduced, including ensuring that cancer survivors who are at risk of complications receive consultant-led antenatal care.

“These data are important because they provide much-needed detail into complications at pregnancy among the AYA cancer survivor population,” says Don S. Dizon, MD, FACP, professor of medicine and surgery at Brown University in Providence, Rhode Island, editor-in-chief of CA: A Cancer Journal for Clinicians, and director of the Pelvic Malignancies Program at the Lifespan Cancer Institute.

“That survivors from cervical cancer and leukemia reported more complications means we can individualize our approaches to these women when they are pregnant. But I also think that the lower-than-expected birth rates seen in AYA survivors of breast, GU, and cervical cancers should give us pause and requires further study.”