Does Your Brain Actually Shrink During Pregnancy? Gynaecologist Answers

You must have heard about ‘mommy brain’?“ It refers to the absent-mindedness and mental fog that some mothers experience after the birth of their children. Have you ever wondered what causes forgetfulness in new moms? Many people believe that women’s brains shrink during pregnancy, which changes how their mind functions. Is it a myth or reality? To understand the reality and science behind this, we interacted with a top gynaecologist.

Let us take a look at what Dr Lavanya Kiran, Director and Lead Consultant, Obstetrics, Gynaecology, KIMS Hospitals, Electronic City, Bengaluru, has to say about this.    

Does the Brain Really Shrink During Pregnancy? 

Let us straightaway get to the point: can your brain really shrink during pregnancy? Answering this, Dr Kiran says, “I often reassure expectant mothers that pregnancy does not cause permanent ‘brain shrinkage’ or loss of intelligence. However, studies using brain imaging have found measurable changes in the brain during pregnancy, particularly reductions in grey matter volume in certain regions. These changes are thought to be linked to the major hormonal and neurological adaptations that prepare the brain for motherhood.”

The expert further explains, “During pregnancy, there are changes in hormones such as oestrogen and progesterone, as well as in blood flow, sleep patterns, stress levels, and metabolic rate. In some cases, women might suffer from something known as ‘pregnancy brain’, which means forgetting things, having difficulties in focusing and being distracted, losing track of what one is doing, or feeling mentally sluggish. This condition does not cause serious harm and passes after delivery.”

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How Pregnancy Affects Your Brain

A 2002 study, published in the American Journal of Neuroradiology (AJNR), used MRI scans to track the brain sizes of women during and after their pregnancies. The researchers discovered that a woman's brain gradually reduces in overall size as her pregnancy progresses. This shrinking effect reaches its peak just as the mother reaches full term and is ready to deliver. While the brain tissue itself gets smaller, the fluid-filled spaces inside the brain increase in size. This specific pattern of brain shrinkage and fluid expansion was seen consistently in the pregnant women who were studied, as a part of this research. 

The researchers also examined pregnant women who developed preeclampsia, a dangerous blood pressure condition. They discovered that women with preeclampsia had significantly smaller brain sizes, as compared to healthy pregnant women. This size difference in preeclamptic mothers was evident, both right post giving birth and in the weeks after delivery. 

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The study further adds that physical changes in the brain during pregnancy are actual, measurable structural shifts. However, the shrinking of the maternal brain is completely temporary; it starts to reverse after childbirth. In the weeks post delivery, the mother's brain tissue gradually begins to increase in volume again. Moreover, the enlarged fluid spaces within the brain start to shrink back to their normal size. 

The finding states that by the time a mother is six months postpartum, her brain fully returns to its original pre-pregnancy dimensions. While these structural changes are highly predictable, researchers are still attempting to understand the exact mechanisms that are causing them. 

Tips to Deal With Brain Changes During Pregnancy

Dr Kiran says that in order to cope with the changes in brain during pregnancy, women need to: 

• Get enough sleep.
• Exercise on a regular basis.
• Have a nutritious diet including protein, iron, omega-3 fats, and other necessary nutrients.
• Drink plenty of water.
• Use reminders.
• Stick to a routine.
• Try not to multitask.

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“At the same time, serious confusion, memory issues, frequent headaches, vision changes or other neurological symptoms should not be associated with pregnancy and require medical attention,” concludes Dr Kiran.

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Conclusion

Experiencing ‘pregnancy brain’ can be frustrating. But these structural changes and temporary brain shrinkage are natural physiological adaptations. They prepare expectant mothers for parenthood. MRI studies have discovered that these physical shifts in brain volume are completely reversible. In fact, the maternal brain returns to its pre-pregnancy dimensions within six months after giving birth. Moreover, new moms can effectively manage these temporary cognitive challenges by prioritising sleep, nutrition, hydration, and structured routines. However, if you witness severe or unusual neurological symptoms, such as extreme confusion or vision changes, promptly consult a healthcare professional.