Challenge No. 1: PMS
The lowdown: Premenstrual syndrome is the range of symptoms that occur 5 to 11 days before your period, thanks to plummeting levels of estrogen and progesterone. Warning: PMS can worsen in your 40ssince hormone levels tend to fluctuate even more widely during perimenopauseand whenever you're stressed out.
What it feels like: What doesn't it feel like? Hello, breakouts, sore breasts, bloating, diarrhea, headaches, backaches and mood swings.
Rx: Lifestyle changes can help a lot. Limiting salt intake minimizes fluid retention and bloating; getting enough sleep and exercise will boost your odds of feeling good during this phase. If you get PMS like clockwork, you could start taking a low-dose birth-control pill to stabilize your estrogen and progesterone levels. If none of the above works and your mood swings are severe, it's possible that you might have premenstrual dysphoric disorder (PMDD). Talk to your doctor: Taking an antidepressant such as Zoloft or Prozac can help.
Challenge No. 2: Pregnancy
The lowdown: That plus sign on your pregnancy test means there is human chorionic gonadotropin (hCG), a hormone made by the placenta after conception, in your systemsending estrogen and progesterone levels surging. They drop dramatically after childbirth and stay low if you're breast-feeding.
What it feels like: Blame hCG for morning sickness in the first trimester. Rising estrogen and progesterone levels make your breasts larger. They also dilate your blood vessels, leading to relaxed joints and muscles, which can cause back pain. The drop in hormones after giving birth can result in moodiness for a few weeks.
Rx: Ease nausea by eating small, frequent meals. Your doctor might recommend vitamin B6 or prescription meds if your vomiting is really bad. After pregnancy, if you have baby blues that just won't go away, you might have postpartum depression. Don't be afraid to talk to your doctor, who can prescribe antidepressants (some are safe to take while nursing) or even low levels of estrogen. Therapy can help, too.
Challenge No. 3: Perimenopause
The lowdown: Anywhere from 2 to 10 years before menopause, you enter perimenopausewhen your ovaries start to produce less estrogen. "It's those wild estrogen fluctuations that lead to all kinds of symptoms," says Sarah Berga, MD, chair of ob-gyn and women's health at Wake Forest Medical Center in Winston-Salem, N.C.
What it feels like: The most (in)famous sign is hot flashesintense heat spreading from your head down through the body. These can cause night sweats. "The estrogen swings appear to disrupt your brain's hypothalamus, which regulates your body temperature," Dr. Berga says. You might also suffer grouchiness, insomnia, irregular periods and vaginal dryness.
Rx: Start with some deep, slow breathing: Done 15 minutes twice a day, it significantly reduces hot flashes, according to a 2012 Mayo Clinic study. So does working out. As with PMS, birth-control pills can help with overall symptoms. Your ob-gyn can also prescribe antidepressants or the antiseizure drug gabapentin for flashes, and estrogen cream for down-there dryness.
Challenge No. 4: Menopause
The lowdown: You've officially hit the big M when you haven't had a period for at least 12 months, meaning your ovaries have stopped producing estrogen and progesterone. The average American woman reaches menopause at age 51. The good news: No more worrying about birth control or PMS! The bad: When you lose estrogen, you lose its protective effects on your heart and bones, so your risk of osteoporosis and heart disease rises.
What it feels like: You may still have hot flashes for a few more years, due to residual hormones in your body. You may experience a lower sex drive; many women also report temporary "mental fog."
Rx: A low-dose vaginal estrogen or tablet can ease dryness. If hot flashes or night sweats really plague you, you might talk to your doctor about hormone replacement therapy. Despite recent controversy, the latest expert consensus is that short-term HRT is the best treatment for menopause symptoms, especially in women younger than 60. But there's no need to do anything: Menopause is a natural part of life, and most symptoms should eventually disappear.