Lo Loestrin Fe Vs. Loestrin Fe: What Is The Difference?

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Both Lo Loestrin Fe and Loestrin Fe contain the same hormones (ethinyl estradiol and norethindrone), but in different amounts, with Lo Loestrin Fe containing lower amounts of estrogen.

In addition, Lo Loestrin Fe is considered an "extended-cycle" birth control pill, as it contains 26 "active", hormone-containing pills, compared to the 21 active pills that Loestrin Fe contains (except for Loestrin 24 Fe which has 24).

Lo Loestrin Fe Vs. Loestrin Fe: Differences

There are several differences between these birth control pill products, with the main differences being:

• Lo Loestrin Fe contains 10 mcg ethinyl estradiol per active pill.

• Loestrin Fe contains 20 mcg or 30 mcg ethinyl estradiol per active pill, depending on the product.

• Lo Loestrin Fe is an "extended-cycle" birth control pill, meaning it contains more than the usual 21 days of hormone-containing pills, although it maintains the conventional 28-day cycle. Each cycle of Lo Loestrin Fe contains:
• 24 pills containing 10 mcg ethinyl estradiol and 1 mg norethindrone acetate (a progestin)
• 2 pills containing 10 mcg ethinyl estradiol
• 2 pills containing ferrous fumarate 75mg

• Loestrin Fe contains the traditional 21 days of active pills (20 mcg ethinyl estradiol and 1 mg norethindrone acetate or 1.5/30, depending on the product) and 7 days of placebo pills (that contain ferrous fumarate). The exception is Loestrin 24 Fe which contains 24 days of active pills.

Lo Loestrin Fe

As shown above, Lo Loestrin Fe contains only 10 mcg of estradiol for 26 days, the lowest amount of estrogen contained in any combined hormone birth control pill. This is compared to the 20 or 30 mcg of estrogen contained in Loestrin Fe.

Lower doses of estrogen are intended to lessen estrogen related side effects, such as:

• Nausea
• Vomiting
• Bloating
• Decreased libido
• Breast tenderness

However, the trade-off may be that it is less effective in preventing pregnancy than birth control pills that contain more estrogen.

According to the prescribing information for both drugs, about 3 women become pregnant for every 100 per year using Lo Loestrin Fe (97% efficacy) compared to about 2 with Loestrin Fe (98% efficacy). In addition, low estrogen content increases the risk of breakthrough bleeding. 

As Lo Loestrin Fe contains a low amount of estrogen, it is especially important to take the birth control pills consistently, at the same time every day. Taking pills late or missing doses decreases the efficacy of the pills.

Loestrin Fe

There are multiple "forms" of Loestrin Fe:

• Loestrin Fe 1/20 (1 mg norethindrone acetate/20 mcg ethinyl estradiol)

• Loestrin Fe 1.5/30 (1.5 mg norethindrone acetate/20 mcg ethinyl estradiol)

• Loestrin 24 Fe (1 mg norethindrone acetate/20 mcg ethinyl estradiol)

Loestrin Fe 1/20 and Loestrin Fe 1.5/30 are the traditional 21 days of active pills followed by 7 days of placebo pills (containing ferrous fumarate) while Loestrin 24 Fe contains 24 active pills and 4 days of placebo pills (containing ferrous fumarate).

Final Words

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