Is a word often on the tip of your tongue? Do you forget your keys nearly every time you leave home?

If you're pregnant, you might blame occasional memory lapses on pregnancy brain. And research suggests you may have good reason: Forgetfulness during pregnancy appears to be a real phenomenon. Here's why you might experience pregnancy brain fog – and how to cope.

What is pregnancy brain?

Pregnancy brain (sometimes called "momnesia" or "baby brain") refers to the cognitive struggles and brain fog that some women say they experience during pregnancy and sometimes after birth. It involves symptoms including:

  • memory problems
  • forgetfulness
  • poor concentration
  • absentmindedness
  • clumsiness
  • disorientation
  • reading difficulties
  • trouble recalling words and names

When does pregnancy brain start?

While there's no scientific consensus on when pregnancy brain starts, research and anecdotal stories from moms suggest that pregnancy brain is worst in the third trimester. That said, some studies have found that memory loss and other cognitive problems may begin as early as the first trimester of pregnancy.

Is pregnancy brain real?

Plenty of expectant moms say that pregnancy brain is real. And some research suggests that up to 81 percent of pregnant women report having memory lapses or focus problems. However, the overall scientific evidence is mixed.

Some studies show pregnant women have significantly worse memory and cognitive function than those who aren't pregnant, especially in the third trimester. Other research shows that pregnant women do just as well on cognitive tests as women who aren't pregnant.

A 2018 analysis of 20 studies on pregnancy brain found that compared to non-pregnant women, pregnant women performed worse on tests involving memory and executive function – that is, cognitive function related to organizing tasks, remembering details, managing time, and problem-solving.

While the causes of pregnancy brain fog are unclear, there are several theories:

  • Hormones. Pregnancy sends a flood of fluctuating hormones throughout your body. This triggers major physiological changes and may possibly also affect the brain and memory.
  • Trouble sleeping. More than half of women report insomnia and other sleep problems during pregnancy. A consistent lack of sleep has been shown to impact cognitive functions and memory.
  • Stress and anxiety. It makes sense intuitively: You may be distracted by worry or excitement about this new adventure and the major life changes it will bring, which can interfere with your ability to concentrate and remember things.
  • Changes in brain structure. A few small studies suggest that women experience changes to their brain structure during pregnancy. These changes may last for at least six years after giving birth. Researchers theorize that the body is getting rid of neural networks it doesn't need to make the brain more efficient and specialized for motherhood, which may help women to bond with and respond to their babies. They further speculate that changes in brain structure might be associated with impaired memory.

Keep in mind: The research isn't clear that pregnancy brain exists or that it affects every expecting mom. Pregnant women who do notice it typically experience minor, manageable forgetfulness. Having pregnancy brain doesn't mean you aren't as smart and capable as ever.

How to cope with pregnancy brain

Fortunately, you can make small changes to manage forgetfulness during pregnancy. Try these strategies to help you cope with pregnancy brain fog and memory loss:

  • Keep a daily calendar. Use the calendar app on your phone, or carry a small planner with you.
  • Give important objects a "home." Store things you use often, such as keys, in the same place. Or, invest in some high-tech trackers for your keys and wallet.
  • Set alarms and notifications. Schedule alerts for important meetings or tasks on your phone or computer.
  • Take snapshots. If you park your car in a large or crowded lot, snap a photo of the location with your phone. You can also use photos to save visual notes of things like slides at a meeting, event flyers, business cards, and magazine articles.
  • Use a note-taking app. Use an app on your phone to keep track of important information.
  • Try mnemonic devices. When you meet someone new, think of an association to help you remember the person's name. For example, if you meet someone named Lily, imagine her holding a bouquet of lilies.
  • Carry a notebook. Write down everything in a small notebook. It doesn't need to be fancy – just having everything in one place makes it easier to refresh your memory.
  • Try to get good sleep. It can be hard to sleep well during pregnancy, but getting enough sleep will refresh your memory help you stay alert mentally.
  • Exercise. Working out regularly (with your healthcare provider's approval) not only keeps you healthy during pregnancy, it can also sharpen your memory and help you sleep better at night, increasing your alertness during the day.
  • Ask for help. Ask your partner, family, or friends to pitch in with chores, errands, and childcare. A lightened load means less stress, which can affect your ability to remember things.
  • Simplify. Take a break from multitasking and prioritize what's necessary and what's not. Save your energy for the things that are really important to you.

A little forgetfulness during pregnancy is normal. However, if you're having a lot of trouble thinking or concentrating, if you're feeling sad every day for most of the day, or if you notice a loss of interest or pleasure in things you normally enjoy, you could be suffering from pregnancy depression.

Any time you're feeling unusually sad or overwhelmed, talk to your doctor or midwife so you can get the help you need.