What Week does pregnancy brain start

Dr Yvonne Bohn tells Romper that sleep deprivation and fatigue can lead to forgetfulness and cognition issues, possibly leading to “pregnancy brain.”

Pregnancy brain can occur as early as the first trimester since that’s when your hormone changes are the most dramatic, Bohn says. Usually the hormone changes plateau during the second trimester, but as delivery approaches, you may be experiencing insomnia again because of the ever-so-lovely pregnancy symptoms of having to pee a million times throughout the night, being uncomfortable from your bump, having heartburn, or having leg cramps.

When I worked in a law firm’s marketing department, I was surrounded by pregnant women in my cubicle bay. As the department’s copy editor, I was used to being asked grammar and spelling questions, but I noticed a surge in the questions from my co-workers once they announced they were pregnant, and they all blamed it on the dreaded “pregnancy brain.” So when does pregnancy brain start, exactly? It may be good information to know, even if you aren’t expecting, so you can cut the loved one in your life a break if they misplace their sunglasses on top of their head. If you are expecting, while frustrating, just know that pregnancy brain won't last forever (even if it feels like it).

Though the term pregnancy brain obviously has the word “brain” in it, ironically enough, it’s not from any structural changes in your brain, according to studies. Dr. Yvonne Bohn, OB-GYN at Providence Saint John’s Health Center in Santa Monica, California, tells Romper it’s the dramatic change in hormone levels. “Estrogen and progesterone levels rise rapidly, causing multiple physiologic symptoms ranging from nausea, fatigue, and insomnia. Sleep deprivation and fatigue can lead to forgetfulness and cognition issues, possibly leading to the infamous ‘pregnancy brain,’” she says. Insomnia and fatigue definitely contribute to cognition issues — have you ever had a fitful night’s sleep and couldn't seem to function the next day?

Pregnancy brain can occur as early as the first trimester since that’s when your hormone changes are the most dramatic, Bohn says. Usually the hormone changes plateau during the second trimester, but as delivery approaches, you may be experiencing insomnia again because of the ever-so-lovely pregnancy symptoms of having to pee a million times throughout the night, being uncomfortable from your bump, having heartburn, or having leg cramps. “Anything that can cause interrupted sleep can impact cognition and memory,” Bohn says. Thus, causing “pregnancy brain.”

Pregnancy brain is the pits, no doubt. Thanks to hormones, it occurs pretty early on in pregnancy, but luckily, there is a break during your second trimester. Now, once the baby is born, is there such a thing as “postpartum brain” from lack of sleep? (Actually, I think it's just called motherhood.)

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What Week does pregnancy brain start

Pregnancy-induced brain fog is a true (and truly frustrating) hallmark of pregnancy. If you suffer from so-called "pregnancy brain," you may forget appointments, what you just walked into the store for, where you left your purse, whether you turned off the stove — and, maybe, your phone number.

This forgetfulness isn't just a lack of sleep playing tricks on you: Research suggests that pregnancy really does alter a woman's brain.

What causes pregnancy brain?

As usual, pregnancy brain is just your hormones having some fun — this time at the expense of your memory.

A lack of quality shut-eye due to a number of sleep-busting conditions during pregnancy (especially common in your first and third trimesters) can also play a role, as can the fact that you're constantly zapped of energy (which your brain needs to stay focused).

What’s more, all of those big and exciting changes going on in your life could have an impact on your ability to focus too.

In fact, research has actually shown that your brain really does function differently during pregnancy, increasing activity in the side associated with emotional skills (in theory to ensure you’re neurologically attuned to your baby’s facial emotions at birth, so you bond more easily).

And believe it or not your brain-cell volume actually decreases during the third trimester of pregnancy (which could explain why you can't remember what you just read about in that last paragraph). Trusted SourceNature NeurosciencePregnancy Leads to Long-lasting Changes in Human Brain StructureSee All Sources [1] Not to worry, though — your brain will plump back up a few months after delivery.

Is pregnancy brain normal?

Forgetfulness is both completely normal and extremely common during pregnancy. Even if you pride yourself on your master multitasking skills or your ability to stay organized, you still may find yourself having trouble concentrating or remembering your car keys.

The good news is it’s also temporary — you'll have total recall again long before you start to have your "senior moments."

What you can do about it

  • Take a deep breath. Try not to be too hard on yourself. Stress can cloud your pregnancy brain more.
  • Write it down. If you need to remember something — to buy certain groceries, make a phone call, ask your practitioner a question, take your prenatal vitamin — leave a big note in an obvious place. You might also stash a notepad and pen in easy-to-remember spots like your purse, your car and your bathroom.
  • Use an app. Rely on calendar reminders on your phone to help keep you organized and less forgetful.
  • Have a backup system. Reduce the number of things you need to remember by delegating some jobs to others. When possible, enlist the aid of those around you who are not pregnant to serve as your backup system (Honey … have you seen my headphones?). Easier said than done, but worth a go. (You'll forget about the less important stuff, anyway.)
  • Have a sense of humor. Let yourself have a good laugh about this hazy stage, and encourage your partner to do the same. Who cares if you left your headphones in your dresser?
  • Chow down on choline. This mineral is the building block for a memory-forming brain chemical called acetylcholine. Researchers believe that eating plenty of choline-rich foods during pregnancy may help boost the function of your brain and your baby's. Trusted SourceThe FASEB JournalMaternal Choline Supplementation During the Third Trimester of Pregnancy Improves Infant Information Processing Speed: A Randomized, Double-Blind, Controlled Feeding StudySee All Sources [2]
  • Load up on omega-3s. DHA-rich foods (including pregnancy-safe fish like salmon) also support healthy brain function and development for both you and your baby.
  • Skip the gingko. Forget about taking the herbal supplement gingko biloba. This "memory-booster" has not been proven safe for use during pregnancy.
  • Prepare yourself. Expect the haze to hang in during the first weeks to months after you give birth. Postpartum fatigue may take the place of hormones as the primary culprit, but that too shall pass.

Weirdest Pregnancy Symptoms

  1. Nature Neuroscience, Pregnancy Leads to Long-lasting Changes in Human Brain Structure, December 2016. | Show in the article
  2. The FASEB Journal, Maternal Choline Supplementation During the Third Trimester of Pregnancy Improves Infant Information Processing Speed: A Randomized, Double-Blind, Controlled Feeding Study, March 2018. | Show in the article
  3. What to Expect When You're Expecting, 5th edition, Heidi Murkoff.
  4. WhatToExpect.com, Pregnancy Nutrition Chart: 32 Essential Nutrients for Pregnant Women, June 2022.
  5. WhatToExpect.com, 8 Scientific Signs That You're Having a Boy or a Girl, February 2022.
  6. Women’s Brain Health Initiative, Choline, A Nutrient Most of Us Don’t Get Enough of, Essential for Brain Health, December 2018. 

August 16, 2022

Editor: Caroline Picard

  • Minor copy and formatting changes.
  • Medically reviewed to ensure accuracy.

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