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Why are my periods heavier in my 40's?

Why are my periods getting heavier as I get older

If you've noticed your menstrual flow becoming heavier you are not alone. Because of course, right? So many menstrual changes are happening that Mother Nature couldn't let that one slide too!

Just to recap, the first changes you may notice with your menses as you make your way through your 40s include:

  • your total menstrual cycle (time between the first bleed days of your periods) becomes shorter, and then longer

  • heavier menstrual flow

  • changes to your PMS symptoms - some periods may skip symptoms entirely

  • you might start noticing (possibly intermittent) symptoms you normally associate with menopause such as hot flashes, irritability or depression, sleep issues.

So WHY does your period get heavier!? I think this is neat and wanted to take the time to explain ONE of the hormonal causes. First, let me just refresh everyone's memory on what is happening during a typical menstrual cycle:

typical menstrual cycle


FSH is released and triggers follicles to grow. One ends up dominating in growth and takes over. As the follicle increases in size, its begin to release estrogen and a low level of progesterone into your blood.

Later in this phase, as the follicle-stimulating hormone level decreases, usually only one follicle continues to develop. This follicle produces estrogen. Estrogen levels increase steadily.

Ovulation occurs on about day 14 of a 28-day menstrual cycle. This begins with a surge in luteinizing hormone and follicle-stimulating hormone levels. Luteinizing hormone stimulates egg release (ovulation), which usually occurs 16 to 32 hours after the surge begins. The estrogen level decreases during the surge, and the progesterone level starts to increase.


During the luteal phase, luteinizing hormone and follicle-stimulating hormone levels decrease. The ruptured follicle closes after releasing the egg and forms a corpus luteum, which produces progesterone. During most of this phase, the estrogen level is high.

If the egg is not fertilized, the corpus luteum degenerates and no longer produces progesterone, the estrogen level decreases, the top layers of the lining break down and are shed, and menstrual bleeding occurs (the start of a new menstrual cycle).

If the egg is fertilized, the corpus luteum continues to function during early pregnancy. It helps maintain the pregnancy.

Luteal Out Of Phase Cycles (LOOP Cycles) and Heavy Periods

The very first hormonal changes that happen as the sun sets on your fertile years is the drop in Anti-Mullerian Hormone (AMH) and Inhibin B. As these change, they trigger a higher amount of Follicle Stimulating Hormone (FSH) to be consistently released. It's YELLING at your ovaries. This is a big change from the cycle above, where it starts gently and then increases around ovulation. The FSH causes a follicle to grow. But the FSH stays high... so more follicles begin to grow. These follicles are not synced up and kind of doing their own thing. They're all contributing to hormone production though, particularly estrogen. So we get a good amount of FSH, and a good amount of estrogen. But these aren't very robust follicles and the progesterone production they lend to is pretty wimpy. The estrogen is helping get that uterine lining nice and thick as it hopes to get ready for an egg to implant in it. Sometimes they can trigger ovulation, and sometimes they don't. If the follicle growth began in the previous menstrual cycle, it may trigger an early ovulation.

When you do bleed, you're shedding a thicker liner because of the extra estrogen production, paired with poorer progesterone production.

Sometimes the bleeds are also due to the thickness of the uterine lining just being so thick it naturally sheds/leaks - earlier than it would have otherwise. This whole process is referred to as a "Luteal out of phase cycle" or LOOP cycle because everything is happening out of phase (out of sync) with the regular checks and balances.

I hope I made it clear as to why you can also see changes to your cycle length when all this is happening - you might be having a breakthrough bleed or you might have had an early ovulation.

LOOP Cycle graphic showing hormone changes that cause heavy periods
Obstet Gynecol Clin North Am. Author manuscript; available in PMC 2019 Dec 1. Published in final edited form as: Obstet Gynecol Clin North Am. 2018 Dec; 45(4): 613–628. Published online 2018 Oct 25. doi: 10.1016/j.ogc.2018.07.004

Are There Non-Hormonal Causes of Heavier Periods?

Yes. There are some structural/physical causes of heavy periods, which is why it's a good idea to talk with your healthcare provider about screening some of these causes out. These include:

  • Uterine Polyps

  • Fibroids

  • Endometrial Adenomyosis

  • Leiomyomata

  • Endometrial cancer, this is relatively uncommon in women under 45 and is more commonly diagnosed around 60 years old.

  • Clotting conditions

  • Low iron

Treatment Options

If you are having extremely heavy periods due to hormonal changes then progesterone can be a really helpful therapy and can be used as little as 10 days of the month.


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