Pregnant Women’s Hair Can Change Colour... Permanently!

Why Pregnancy Can Change Your Hair… Permanently!

J Fun Fact Friday Leave a Comment


Fun Fact Friday – WEEK 170

Pregnant Women’s Hair Can Change Colour, Permanently!


Pregnancy can be a crazy ride for some, full of twists, turns and unknowns. The hormones associated with it can leave some women with stretch marks, others with changes to their brain and memory, some get a change in shoe size, whilst for others, their appearance can be forever altered.

This week we’re looking at the changes a pregnant woman’s hair can undergo and what hormones are responsible for those changes. Changes in thickness, oiliness and straightness can all be affected. And, for some, they even experience a permanent change in their hair colour.



A woman’s body goes through many changes during and after pregnancy. Most of those changes are caused by the mass of baby-growing hormones that accompany pregnancy. A woman’s hair is susceptible to these hormonal changes and, as a consequence, some women can see some startling changes in the hair department.

Thickening or thinning, straightening or curling, the way hair can change will be all down to each woman’s specific makeup and how their body responds to the hormonal changes. Some may see a deviation from their expected levels of oiliness or dryness and can also find new hair growth – sometimes making appearances in the least desirable of places.

The most common change is a thickening of their hair. This happens because the normal hair growth cycle is interrupted by the influx of hormones. Normally, hair has a growth cycle and a rest cycle. Growth cycles last several years, but the rest phases last just a few months. At any given point in time, some of your hair will be in the resting phase and you can expect to lose a hundred or so hairs a day. That is unless you are pregnant.

Most pregnant women’s hair doesn’t go into the resting phase during their pregnancy. They see a dramatic reduction to the usual loss of hair. As a consequence of this, women end up with a thicker head of hair by the end of their pregnancy.

The hormone responsible for interrupting the hairs cycles is oestrogen. Oestrogen production soars during pregnancy. Its production is so high that pregnant women can produce more oestrogen in a single day than non-pregnant women do in three years – something we discovered way back in our fifth FFF.

Oestrogen is also one of the hormones responsible for some women experiencing an apparent increase in the size of their nose. If you’re feeling nosey, go check out week 139 for a pun-filled look at this subject.

Oestrogen imbalances can affect a woman’s hair at any stage in her life. But, never is this truer than at about 3 – 4 months after birth. This is the time when many new mothers have a potentially dramatic loss of hair. But, it’s not as dramatic as it may first appear. Triggered by the levels of oestrogen returning to normal, those hairs that would have been lost during pregnancy, but weren’t, all decide to make a break for it in one fell swoop. The consequence is that, in a small space of time, women experience hair loss that would normally have taken place over several months.

Oestrogen’s increase is also accompanied by a rise in progesterone and some androgens (male hormones). These altered levels can cause your hair follicles to produce different levels of sebum. Sebum is a natural oil that your body makes and it keeps your skin moisturised and helps give your hair have a glossy appearance. These differences in sebum levels, during pregnancy, can cause hair to deviate from its normal levels of oiliness or dryness.


Progesterone is one of the hormones responsible for inhibiting pregnant women from lactating early in their pregnancy. If progesterone and oestrogen weren’t present, then a pregnant woman would be producing breastmilk from around 4 months into pregnancy. It’s only when their levels drop that prolactin is able to do its work and often happens a day or two after birth.


Soaring oestrogen levels can also cause other changes to a pregnant woman’s hair. The hair’s follicle can actually change shape; creating curls on those with straight hair or straightening even the curliest of locks. Along with the varying levels in sebum, the follicle’s shape change can also alter the hair’s texture.

The appearance of extra hair, sometimes in less desirable places, is due to the increased levels of androgens in the body. This can be particularly concerning for those women that see a change in hair colour – especially if that change is a darkening in colour, instead of a lightening. Hair colour changes in pregnancy are caused by another hormone that alters during pregnancy; melanin.

Melanin, as we discovered in week 36, causes something called “The Mask of Pregnancy” or pregnancy melasma. The mask of pregnancy is hyperpigmentation of the skin. It is fairly common, thought to affect up to 90% of pregnant women and varies in intensity from woman to woman. For some women, it can cause large patches of darkened skin, whilst others are just afflicted with the characteristic radiant glow associated with pregnancy.

Although it is far less common, for some women these melanin changes affect their hair colour. How each woman reacts to the changes may differ. Some will experience no change, whilst others may experience a dramatic lightening or darkening. There are reports of blondes going red, brunettes becoming blonde and vice versa.

One colour change that may have more to do with diet, and less to do with melanin, is when pregnancy brings grey hairs. Whilst going grey is related to melanin production, during pregnancy it can be a red flag that your nutrition isn’t what it should be. For instance, greying hair is one symptom of a vitamin B12 deficiency – something that vegetarians and vegans can be particularly susceptible to. Grey hair can also be a symptom of deficiencies in vitamins D, E, B6, biotin (B7), pantothenic acid (B5), and it is thought it could also be linked to many others.



For those women that see a change in their hair colour, some will want to intervene using modern hair colouring methods. But, pregnancy makes that a far trickier task. Concerns around the chemicals involved in some processes can make finding the right solution tricky. Even then; colours, dyes and chemicals can all behave differently than expected, even if they have been used successfully before. This is particularly true when using dye to cover grey hair, which is normally more resistant. Combine grey hair with pregnancy hormones, and you’ve got hair that is super resistant to colour change.

Hair usually returns back to its usual growth patterns around a year after birth but may take up to two. Some suggest that breastfeeding may delay some changes because breastfeeding involves many of the associated hormones. But, there’s little knowledge in this area, and most anecdotal evidence points at a delay, or reduction, associated with the sudden loss of hair after birth.

Whilst most women’s hair does return to normal, there are a minority whose changes become permanent. The hormonal changes needed to turn a woman’s body into a baby producing paradise, sometimes come with unintended consequences. For some, those changes are insignificant or tolerable. Whilst, for others, it’s far less bearable.

If you’re tempted to adjust your hair whilst pregnant, be sure to talk to a medical professional and your hair stylist for all available options. If not, then just chalk it up to another part of the wild ride that is pregnancy. But remember, there is an end to that crazy ride. An end that makes it worth every single twist, turn and unknown.


Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.