translation - What does 揺らぎやすい女性 mean?

I was translating a passage the other day for a health spa and came across the following passage:

揺らぎやすい女性のための限定メニューができました。
1ヶ月の周期の中で、私たちの体は大きく変化します。
生理は、体をととのえる絶好のチャンス。
より快適に過ごせる体づくりをお手伝いいたします。

I was a little befuddled by 揺らぎやすい because it obviously doesn't mean easily fluctuating women. I gather from the rest of the passage and some precursory Google searches, it has a meaning similar to 'women with menstruation problems', but I'm not sure if that is the exact meaning or not. Can anyone clarify?

And sorry I was unable to talk to the spa for clarification. I was working through an agent and it needed to be done quickly.

Answer

揺らぎやすい女性 is not an idiomatic phrase, and it is not until you read the second line that you can tell what it actually refers to. The meaning of 揺らぐ here is clearly described in the second line, "私たち(女性)の体が大きく変化する" due to the menstruation cycle.

But I think 揺らぎやすい女性 is a misleading expression.

We have two 和語 verbs which use this kanji: 揺【ゆ】らぐ and 揺【ゆ】れる.

We mainly use 揺れる for physical vibration/swinging/fluctuation. 「揺れる女性」 or 「振動する女性」 is obviously funny in this situation (振動する always refers to physical vibration).

The primary meaning of 揺らぐ is "to lose control/balance, become unstable, be about to collapse". And 揺らぐ is far more commonly used against intangible/mental things: 「決心が揺らぐ (lose determination)」「信頼が揺らぐ (lose confidence)」「気持ちが揺らぐ (be disconcerted)」「計測値が揺らぐ (measurements become inconsistent)」.

If I see 揺らぎやすい女性 without any further context, it comes off to me as something like "mentally unstable woman", or "indecisive woman". I think this ad should have said at least "体調が揺らぎやすい女性" in the first line to avoid confusion.