First trimester
Learning Center
Marijuana and depression: What's the link?
Marijuana and depression seem to go hand in hand for some people, but there's no clear evidence that marijuana directly causes depression.
Menopause and high blood pressure: What's the connection?
For many women, menopause and high blood pressure seem to go together. Discover why.
Menopause hormone therapy: Does it cause vaginal bleeding?
Some forms of hormone therapy prescribed to ease hot flashes and other menopause symptoms may cause vaginal bleeding. Learn more.
Migraines: Are they triggered by weather changes?
Migraines — Are they triggered by weather changes?
Mononucleosis and Epstein-Barr: What's the connection?
The Epstein-Barr virus sometimes causes a disease known as mono. Learn who is at risk and what the symptoms are.
Narrow stools: Should I be concerned?
Narrow stools may be a sign that the colon is narrowing or has a blockage.
Natural breast enhancement: Do supplements work?
Breast enhancement supplements haven't been proved effective, and they could cause side effects.
Nausea during pregnancy: A good thing?
Morning sickness is common during pregnancy. Understand what nausea and vomiting might mean while you're pregnant.
Nighttime headaches: How can I get relief?
"Alarm clock" (hypnic) headaches wake people up. But other nighttime headaches also can disrupt sleep. Relief begins with determining the cause.
Nocturnal panic attacks: What causes them?
Nighttime panic attacks can cause sweating, rapid heart rate, trembling, shortness of breath, heavy breathing, flushing or chills. Learn about treatment.