Some common but mild side effects generally decline as patients acclimate to the new hormone levels. The most frequently reported side effects are:

• Breast pain
• Headaches
• Abdominal pain
• Menstrual cramps in premenopausal women
• Bloating, gas, or nausea
• Depression
• Vaginal discharge

There can be some rare but more serious side effects. Sudden allergic reactions such as severe dizziness or trouble with breathing, a rash or itching, or swelling of the face, tongue, or throat should be reported to an emergency healthcare facility as soon as possible. 

Other symptoms that must be reported to your doctor immediately include:

• Signs of a heart attack such as chest pain, tightness, or pain radiating up to your shoulder, arm, neck, or jaw.
• Signs of a stroke, like sudden trouble talking, trouble walking, or numbness on one side of your body or face
• Sudden, severe headaches
• Breast lumps or acute pain in the breast
• Unusually heavy or irregular vaginal bleeding

Before starting to use, read the manufacturer’s Product Insert that comes with the medication. Please note that not all side effects can be listed here. Consult a healthcare provider if you experience any of these or other unexpected side effects.

Prempro is prescribed to relieve the symptoms that may accompany the start of menopause. The main symptoms are 

• hot flashes
• night sweats
• mood changes
• loss of sex drive
• discomfort during sexual intercourse because of vaginal dryness
• osteoporosis (bone density loss) that can lead to fractures. 

In the earlier phases of perimenopause, some women experience difficulty sleeping, weight gain, or thinning hair.

Women usually enter menopause from their mid-40s onwards. In early perimenopause, estrogen and progesterone levels begin to fluctuate, leading to changes in menstrual cycle length and flow. Further into perimenopause, ovulation may become irregular or cease altogether. A woman is considered to have reached menopause after twelve consecutive months without a menstrual period (amenorrhea).

From the start of menopause, there will be steep declines in estrogen and progesterone levels as the ovaries gradually reduce their production.