Fertility treatments in Canada are an eligible medical expense (ref .https://www.canada.ca/en/revenue-agency/services/tax/technical-information/income-tax/income-tax-fol...). And, medical expenses outside of Canada are eligible for the medical expenses deduction (ref. https://www.canada.ca/en/revenue-agency/services/tax/technical-information/income-tax/income-tax-fol...), so it stands to reason that fertility treatment expenses paid outside of Canada are eligible. But, it wouldn't hurt to double-check directly with the CRA.