Kelnor 1/35 28 Day Side Effects: What to Expect and When to Call Your Doctor

Starting any new oral contraceptive comes with questions about what to expect. Kelnor 1/35 28 Day — a combination pill containing ethynodiol diacetate and ethinyl estradiol — has a well-documented side effect profile. Most patients tolerate it well, but like all hormonal contraceptives, it can cause both minor and, in rare cases, serious adverse effects. This guide covers what's normal, what to watch for, and when to contact your healthcare provider.

The Boxed Warning: Smoking and Cardiovascular Risk

Kelnor 1/35 carries an FDA boxed warning — the most serious type of warning in prescription drug labeling. The warning states: cigarette smoking increases the risk of serious cardiovascular side effects from oral contraceptive use. This risk increases with age and with heavy smoking (15 or more cigarettes per day) and is quite marked in women over 35 years of age. Women who use oral contraceptives should be strongly advised not to smoke.

Common Side Effects (Often Improve Within 1–3 Months)

The following side effects are commonly reported with Kelnor 1/35 and similar combination oral contraceptives. Many resolve on their own after the first 1–3 months as your body adjusts to the hormones:

Nausea — most common in the first few weeks. Taking the pill with food or at bedtime can help.

Breast tenderness or swelling — often diminishes after the first 1–2 cycles.

Breakthrough bleeding or spotting — light bleeding between periods is common in the first 1–3 months; notify your provider if it continues beyond 3 cycles.

Headache — mild headaches are common. Severe or new-onset migraines, especially with visual disturbances (aura), require immediate medical attention.

Changes in libido — some patients report decreased or increased sex drive.

Mood changes — some patients experience mood swings, irritability, or depressive symptoms. Inform your provider if depression becomes significant.

Weight changes — minor weight fluctuations are sometimes reported, often related to water retention rather than fat gain.

Skin darkening (melasma) — blotchy dark patches can appear on the face with sun exposure. Use sunscreen and avoid tanning beds.

Contact lens intolerance — some patients develop discomfort wearing contacts; see an eye doctor if this occurs.

Serious Side Effects: Seek Emergency Medical Care Immediately

While rare, serious adverse events associated with combination oral contraceptives require immediate medical attention. Stop taking Kelnor 1/35 and call 911 or go to the emergency room if you experience:

Signs of a blood clot: sudden chest pain, shortness of breath, coughing up blood (pulmonary embolism); severe leg pain, swelling, or warmth (deep vein thrombosis); sudden severe headache, vision changes, difficulty speaking (stroke)

Heart attack symptoms: crushing chest pain, pain radiating to the arm or jaw, shortness of breath, cold sweats

Liver problems: severe abdominal pain, jaundice (yellowing of the skin or eyes), dark urine

High blood pressure: severe headache, blurred vision, nosebleed, shortness of breath (symptoms of hypertensive crisis)

Vision changes: sudden vision loss or changes may signal retinal thrombosis — stop the pill and seek immediate care

Severe allergic reaction: hives, difficulty breathing, swelling of the face, lips, tongue, or throat

Who Should Not Take Kelnor 1/35?

Kelnor 1/35 is contraindicated in people who:

Have or have had blood clots (DVT or pulmonary embolism)

Have had a stroke or heart attack

Have or have had breast cancer

Have active liver disease or liver tumors

Are pregnant or suspect pregnancy

Are over 35 and smoke cigarettes

When to Call Your Doctor (Non-Emergency)

Contact your healthcare provider (during business hours) if you experience:

Breakthrough bleeding that persists beyond 3 months

Missed periods (especially two in a row) — rule out pregnancy

Worsening depression or significant mood changes

New or worsening headaches

Elevated blood pressure readings

Also see our related guide: Kelnor 1/35 drug interactions: What to avoid and what to tell your doctor.