You can't say that Apple (NASDAQ:AAPL) didn't warn you. During the earnings conference call in October, CFO Luca Maestri warned investors that Apple could face significant headwinds from foreign exchange fluctuations, like many other tech companies are experiencing right about now.

Well, falling oil prices and sanctions have caused the Russian ruble to fall to record lows against the U.S. dollar, and as a result Apple has temporarily taken down its online store in Russia. Apple attributed the decision to the currency's volatility, saying that it needed to review pricing.

Russia has always been a tricky market for Apple. The company only opened its online store in June 2013 and still doesn't have its own retail stores.

How currency fluctuations affect Apple
Generally speaking, the U.S. dollar has been strengthening for quite some time, which puts pressure on Apple's international business since those sales translate into less and less dollars back home. A stronger dollar puts downward pressure on recognized revenue abroad, which similarly hurts gross margins. Last quarter, international sales comprised 60% of total revenue, so the impact of foreign exchange fluctuations cannot be understated.

Currency fluctuations didn't have much of an impact in Apple's fiscal fourth quarter. Maestri was expecting Apple to take a hit this quarter, which is factored into its guidance:

When we looked at our Q4 results, actually the impact was fairly limited, the combination of the hedging program and the fact that the dollar really strengthened toward the very end of the quarter, not much impact in Q4. It is becoming a significant headwind in Q1, both on a year-over-year basis and on a sequential basis.

As I said before, we have reflected the new FX situation at current levels into our guidance that we provided for both revenue and gross margins. And it's a fact of life. If the US dollar strengthens, that creates a headwind for us both in revenue and margins for our business outside the United States. As you know, we have a comprehensive hedging program in place that mitigates the impact of foreign exchange.

Apple's hedging program is designed to accommodate natural and expected fluctuations in currency markets, but the ruble's current volatility is far beyond what anyone expected (the ruble fell 15% on Tuesday alone against the U.S. dollar).

The results of Apple's hedging program are included in its other income and expense line item on the income statement, which in total should be around $325 million this quarter.

Apple doesn't want to change prices unless it has to
Analysts also asked if Apple would harmonize prices in the face of currency headwinds, where the company changes pricing to offset fluctuations. Maestri responded, "We price our products in a way that is in general reflective of pricing here in the United States and it's a pricing that we want to keep in place for reasonable periods of time. We do not like to make sudden changes to our pricing."

In the case of a weakening foreign currency, Apple must increase prices in order to fetch the equivalent value in U.S. dollars. Despite Apple's aversion to sudden price changes, it already increased prices in Russia in November. On average, iPhone prices jumped 25%. With the ruble's plunge this week, iPhones could get even more expensive for Russian consumers.