Unassisted pregnancy rates and outcomes in cancer survivors: a systematic review.

IMPORTANCE

This systematic review investigates outcomes for unassisted pregnancies in cancer survivors. Although prior studies have examined pregnancy outcomes for cancer survivors, clarifying the outcomes specifically for unassisted pregnancies can help guide patient and provider expectations and improve fertility preservation counseling.

OBJECTIVE

The primary objective of this systematic review was to identify the impacts of cancer and its treatment on fertility, measured as the live birth rate among cancer survivors with an unassisted pregnancy. Secondary objectives included identifying parental and fetal outcomes of unassisted pregnancies in cancer survivors.

EVIDENCE REVIEW: We searched MEDLINE (PubMed), Embase (Elsevier), Cochrane Library (Wiley), and Scopus (Elsevier) from inception through April 24, 2025. After de-duplication, 1,185 unique citations were subject to blinded independent review by two investigators. Full-text screening was performed on 300 reports and 64 secondary citations. Data extraction was completed for 43 articles for the primary outcome of live birth rates and secondary outcomes.

FINDINGS: This review consolidates the available data on the outcomes of unassisted pregnancies in cancer survivors compared with individuals without cancer. Live birth rates were significantly lower in survivors of breast cancer and individuals who underwent hematopoietic stem cell transplant or abdominopelvic radiation therapy during their cancer treatment. Survivors of breast and gynecologic cancers had higher rates of pregnancy loss, although there were no differences in rates of hypertensive disorders of pregnancy, gestational diabetes, placental abnormalities, or cancer recurrence. Survivors exposed to radiation therapy were more likely to have infants who were small for gestational age or had low birth weight, and survivors of breast cancer were more likely to experience iatrogenic or spontaneous preterm birth. The effects of other types of cancers or treatments were not associated with significant differences in live birth rates or any secondary outcomes in included studies.

CONCLUSION AND RELEVANCE: Although unassisted pregnancy is possible for patients diagnosed with cancer, certain cancers and treatments are associated with decreased live birth rates and increased obstetric and neonatal complications. Individualized fertility preservation counseling throughout the cancer diagnosis and treatment process is an important aspect of comprehensive cancer care that helps patients make informed decisions about their future fertility.