Menopause is defined as 12 months without a period

Postmenopause is a stage lasting roughly a third of a woman's life

Postmenopause is the final stage of menopause, occurring once a woman hasn't had any bleeding for a full year. She is then considered postmenopausal for the rest of her life. While some of the intense symptoms she might experience during perimenopausal will decline, her risk for certain conditions and diseases will increase.

How menopause affects mental health

Menopause, a natural biological process, occurs in three stages: perimenopause (hormone fluctuations), menopause (end of menstrual cycles), and postmenopause (12 months without menstruation). Hormonal shifts during this time can affect neurotransmitters, increasing the risk of mood disorders.

Perimenopause, which typically occurs in a woman's mid-40s, precedes menopause

Sometimes referred to as the menopausal transition, this time period often lasts around 4 years as the ovaries' production of the reproductive hormones progesterone and estrogen decline. It may be accompanied by mental and physical symptoms including irregular periods, hot flashes, sleep issues, mood swings, and alterations to a woman's sex drive.

What is medical menopause?

Medical menopause is when menopause is induced from either surgery or medicine. Chemotherapy and radiation, as well as oophorectomy (a surgical procedure that removes the ovaries) and a radical hysterectomy can cause a woman to become menopausal. Women that go through medical menopause experience the same symptoms as women that experience natural menopause. Learn more about the medical condition here.

Menopause is a hormonal transition point, like puberty

Yet menopause isn't talked about as much. In this podcast episode by Houston Methodist, a Texas-based hospital, the host speaks with a gynecologist with a specialization in menopausal medicine about what menopause really is, and how women and the people in their lives can navigate this next life stage.

By 2030, roughly 6% of the world's population will be in menopause

An estimated 25 million women pass through menopause annually, with a projected increase in the number of women in menopause in both lower-resource and higher-income populations in the years ahead, highlighting the social and economic value of focusing on menopause care.

Menstruation, which occurs monthly, is the release of an unfertilized egg

This routine vaginal bleeding is part of a woman's hormonal cycle and occurs after an egg is released by an ovary during ovulation and isn't fertilized. Also known as periods, this monthly occurrence can cause symptoms including cramping, fatigue, and mood changes.

The gaps in menopause research and their effects

Nearly all studies (99%) researching the biology of aging don’t consider menopause in their setup. A Harvard professor noted that about 75% of aging-related diseases are likely influenced by menopause. In this article, she discusses how gaps in research are negatively impacting how the medical system can effectively treat aging women. Read her analysis of the issue here.

Late-onset menopause lowers osteoporosis risks, but heightens the risks for certain cancers

Defined as when a woman starts to experience perimenopause after age 55, this delayed menopause onset is linked to elevated risk of developing breast, ovarian, and uterine cancers.

Humans aren't the only mammals who go through menopause, but it's rare in the animal world

While scientists are unsure how many mammals actually experience menopause, they do know for sure that humans aren't the only ones. Orcas and some toothed whales (like belugas and narwhals) go through menopause. And a recent study found chimpanzees also experience the condition, though it's late in life.

'Menobelly' is real, with more fat stored around the abdomen as estrogen levels drop

The way fat is carried in the body shifts with menopause, with those pounds increasingly settling around the abdomen instead of the hips and thighs. Exacerbating this phenomenon, muscle mass also begins to decline, so calories stick around longer than usual. Resistance training, including push-ups and planks, alongside a heavier protein diet can help.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Due date is calculated from the first day of the last menstrual period—not when sex occurred

The standard counting system considers a woman pregnant from the first day of her last menstrual period, which means someone may technically—for the purposes of measurement—have become pregnant even before she had sex. This standard starting point is used because it reliably marks when the body began preparing for pregnancy—even though it's typically two weeks before conception. On average, most women are pregnant for 280 days from the last menstrual period.

Why we should care about renaming the hormonal disorder PCOS to PMOS

The new name, polyendocrine metabolic ovarian syndrome, nods to the hormonal disruptions that cause this condition, which affects roughly one in eight women. People with PMOS may have symptoms including irregular periods, trouble conceiving, weight gain, acne, undesired hair growth, and more. The earlier name, polycystic ovary syndrome, was a misnomer because women with the condition don't have cysts in their ovaries. Rather, they have masses that are actually immature follicles. World health experts think the condition often goes undiagnosed.

Measles was declared eliminated in the US in 2000

Following a decades-long vaccination campaign, health officials declared victory over measles. This formal definition does not mean limited outbreaks no longer occur, but that ongoing endemic transmission for longer than 12 months has been prevented.

Mifepristone, approved in 2000, is used to end early pregnancies

The drug works by blocking progesterone, a hormone that is needed to support pregnancy. Mifepristone is typically used in combination with a second drug, misoprostol, because this regimen often causes less cramping and bleeding than just using misoprostol alone.

A recession is commonly defined as two straight quarters of shrinking GDP

Recessions are sustained downturns in the economy. They’re significant, widespread, and there’s no single, surefire way to define or predict them.

Anosmia is the total loss of the sense of smell

This type of loss—due to disease or trauma—has ripple effects, including an altered or limited sense of taste. This video details the anatomy and physiology of our sense of smell and taste and how these senses are interrelated.

Clinical insomnia is defined as trouble sleeping for three nights per week for at least one month

The term "insomnia" is often used in popular culture to refer to general difficulty sleeping or staying asleep. In the US, insomnia transitions to a clinical disorder when symptoms—dissatisfying, nonrestful, and life-disrupting sleep—occur at least three nights per week for at least one month and cause "clinically significant" distress in important areas of life.

Chronological versus biological age

Science has come to understand different types of aging. What we call age is simply the number of years since birth, or chronological age. At the cellular level, biological aging happens at different rates for different people, and explains why some seem to age more quickly (or slowly).

The first year of retirement sets the financial tone for later life

The "first year of retirement" rule says the 12 months after you retire from your career and leave the workforce can set the tone for the rest of your financial life—so it's important to approach it mindfully.

Women were barred from MBA enrollment for half a century

In 1908, Harvard launched the first modern MBA—and only admitted male candidates. The first full-year traditional female MBA students wouldn’t enroll at Harvard until 1963. Learn more about the history of the first women to receive their MBAs on Harvard’s website.

Girlboss founder Sophia Amoruso doesn’t use the word 'girlboss' anymore

An article dives into not only the origin of the term “girlboss,” but also the quotes from the woman who coined the term about her thoughts on the word and the movement around it. In the piece, she explains that she doesn’t identify with or claim the word "girlboss."

Moon's visibility is determined by its declination, equivalent to Earth latitude

The Moon's declination varies between approximately +28.7 degrees and -28.7 degrees, ensuring it rises and sets between latitudes of approximately 61.3 degrees north and south. This means there are places on Earth where the Moon is never visible above the horizon and places where it temporarily does not set.

Non-use or lapsed filings can cause a trademark to expire

Going more than three consecutive years without using a trademark can be considered abandonment—which means the trademark falls into the public domain and someone else could potentially file for the trademark. Besides non-use, not maintaining the paperwork or paying the fees can result in a terminated trademark.

Becoming a man in ancient Rome

In ancient Rome, boys between the ages of 14 and 17 underwent a traditional ceremony marking their transition from childhood to adulthood. This article explores what we know about this common practice and its significance. Learn about the ritual celebration, which included a new white toga, sacrifices, and becoming registered as a citizen.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

A century of Billboard issues documenting the evolution of popular music.

Coral polyps reproduce via broadcast spawning, where entire reefs simultaneously release reproductive cells for about one hour, once a year.

Brandi Chastain, the star of the 1999 US victory over China in the 1999 Women's World Cup, was a last-second choice to take the penalty kick that sealed the victory.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Use this calculator to find the dollar value of your mental load, from meal planning to coordinating after-school care for your children.

In 2026, Finland was named the world's happiest country for the ninth consecutive year based on its wealth, social safety network, and high life expectancy, among other factors.

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

Watch contemporary footage covering the US-backed Shah of Iran fleeing the country in the face of the 1979 Iranian Revolution

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

Poison ivy can cause rashes year-round since all parts of the plant contain urushiol, the oil that triggers our allergic response.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by more than 1.5 million Muslims each year.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

The first robot in literature may have been a 'mechanical man' in 1907's 'Ozma of Oz,' a book in L Frank Baum's 'Wizard of Oz' series.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.