Response to Letters to the Editor from Irit Sinai “Standard Days Method Effectiveness: opinion disguised as scientific review” and Kelsey Wright, Karen Hardee, and John Townsend “The pitfalls of using selective data to represent the effectiveness, relevance and utility of the Standard Days Method of contraception”

Use of Fertility Awareness-Based Methods for Pregnancy Prevention Among Ghanaian Women: A Nationally Representative Cross-Sectional Survey

“…are often classified as modernalthough these classifications are not universal (e.g., the United Nations Population Division does not classify these methods as modern)-and the nomenclature is imperfect. [17][18][19][20][21] In addition to FABMs, some people use menstrual tracking smartphone apps or devices to time sexual intercourse for pregnancy prevention. Although 2 apps have received clearance from the United States Food and Drug Administration for use as a contraceptive method (Natural Cycles in 2018, 22 which also received CE Marking in Europe, and Clue in 2021 23 ), most such apps or devices are not tested or indicated for this purpose and may offer predictions of unknown accuracy regarding the timing of fertile days.…”