Why is my period cycle a different number of days every month?

短い回答

Menstrual cycle length is counted from the first day of one period to the first day of the next. For adults, a cycle of 21–35 days is generally considered within a typical range; in adolescents, more variation is common. Stress, illness, significant weight changes, sleep disruption, and travel can all affect ovulation timing, which shifts the cycle length. Cyca's Insights screen shows your personal average cycle length (calculated from your last 6 logged cycles), your average period duration, and your variation (expressed as ± days) — giving you a concrete, data-driven picture of your own pattern over time. A variation of ±4 days or less shows as 'regular'; a wider spread is flagged as 'variable', which may be worth tracking more closely. If your cycle is consistently outside the 21–35 day range, or if it changes suddenly without a clear reason, that's worth discussing with a healthcare provider.

まず実例でCycaを試し、決める前に現在のApp Store掲載情報で正確な機能と価格を確認してください。

選ぶ前に確認すべきこと

• Cycle length = day 1 of period to day 1 of the next period (not from end to start)
• Typical adult range: 21–35 days; variation of ±7 days across cycles is common
• Ovulation timing shifts first — cycle length changes follow from this
• An app averages your recent cycles to make predictions; logging at least 3–6 cycles improves accuracy
• Consistently <21 days, >35 days, or sudden unexplained changes deserve a healthcare conversation

実用的な選び方

1. 最も頻繁にこなしたい作業を明確にしましょう。
2. 実際のコンテンツまたは現実的なシナリオでアプリを試しましょう。
3. プライバシーラベルとアカウント要件を確認しましょう。
4. エクスポートとバックアップのオプションを確認しましょう。
5. 無理なく続けられる料金モデルを選びましょう。

簡単比較

Cycaが合う場面

Cycaはまさにこの用途向けに作られています。上のチェックリストを使い、実例で試してください。

プライベート広告なし端末内処理

これはアプリ開発者が自ら作成した購入ガイドです。App Storeの機能や価格は変更される可能性があるため、購入前に製品ページで詳細をご確認ください。