Kessous 2016.

Methods	Retrospective cohort.
Participants	A population‐based cohort of consecutive participants who delivered between 1988 to 2013 in the sole hospital of a region in Israel. Participants with known genetic predisposition for malignancy or known female malignancies before or during the index pregnancy were excluded from the study. A total of 106,031 subjects met the inclusion criteria. Follow‐up period was until 2013 and for this study a retrospective follow‐up of hospitalizations due to female malignancies up to 26 years after the index birth was performed. Mean follow‐up, 11.6 years.
Interventions	Any fertility drugs (IVF treatment or ovulation induction).
Outcomes	Endometrial cancer cases identified via linkage to a computerised hospitalisation database. Hospitalisation for the disease during the study period was considered an event. Incident cases in total cohort, 61; in exposed cohort, 8.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Selection bias (comparability)	High risk	Quote:"Patients with known genetic predisposition for malignancy or known female malignancies before or during the index pregnancy were excluded from the study". Comment: Outcome not likely to be present at start. Quote: "The studied population was composed of consecutive patients who delivered between the years 1988–2013". Comment: Non‐exposed drawn from the same population as the exposed cohort. Comment: No comparability on cause of subfertility, diabetes mellitus, polycystic ovary syndrome (PCOS), and obesity was ensured.
Selection bias (confounding)	High risk	Quote: "Statistical significance was calculated using the Chi‐square test for differences in qualitative variables". Quote: "Cox proportional hazard models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for long‐term risk of female malignancies". Comment: Analyses inadequately controlled for potential confounding factors.
Performance bias	High risk	Comment: Exposure to ovary‐stimulation drugs was ascertained by medical records. Blindness regarding the allocated interventions not guaranteed.
Detection bias	Low risk	Quote: "The first hospitalization for female malignancies including ovarian cancer, uterine cancer, cervical cancer and breast cancer at Soroka University Medical Center was considered an event. The exact ICD codes for each type of the female malignancies are presented in the 'Appendix'. Comment: Outcome was ascertained by record linkage.
Attrition bias	High risk	Quote: "However, the ascertainment of malignancies diagnosed in patients that were treated in another hospital could not be accomplished. It is therefore possible that some patients were missed". Comment: Completeness of follow‐up was considered inadequate.
Selective reporting (reporting bias)	Low risk	All of the study’s prespecified (primary and secondary) outcomes that were of interest in the review have been reported in theprespecified way.
Other bias	High risk	Quote: "Patients had a mean follow‐up duration of more than a decade (11.6 years)". Comment: The length of follow‐up was considered adequate. Comment: Non‐RCT study