Postnatal
A first baby at forty: when the postnatal shed and perimenopause arrive together
A third of the mums in my clinic had their first or last baby past 38, and their hair story is different from the one in the leaflets. The postnatal shed happens, and it does not fully recover, and everyone says it is the baby and everyone is half right.
What is different
The postnatal shed is a sudden oestrogen drop. Perimenopause is a slow, jagged one, and it commonly begins between 38 and 45. A woman who has a baby at 40 gets the sudden drop on top of the slow one, and her follicles at the temples and parting — the androgen-sensitive ones — lose their protection twice. For a mum of 28, the postnatal drop is a dip in a high plateau and the follicles climb back out. For a mum of 41, the drop lands on a slope, and the climb back is against the gradient.
Add that ferritin is often lower at 40 after two decades of periods, that older pregnancies are more often IVF (which has its own shed — here) or carry more complications, that the birth is more often a caesarean, and that sleep loss is harder to absorb at 40 than at 28.
How it presents
The shed at three months as usual, then a recovery that stalls. The corners come back finer or not at all; the parting is wider at the first birthday than it was at the twelve-week scan and does not narrow again. Often, alongside, the first perimenopausal symptoms: cycles that came back irregular, sleep that is worse than the baby explains, a change in mood, and hair texture that has gone dry. Many women in this situation assume it is all the baby and wait, and the waiting is exactly wrong, because the perimenopausal component does not resolve on its own.
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Time is the test. A shed that is only postnatal is easing by month six and recovering by twelve. If at twelve months the temples and parting are still going, or have started going again after a partial recovery, the hormonal decline is in play. Blood tests do not help much at this age — why is here — but the pattern does: postnatal shedding is diffuse; perimenopausal thinning is temples, parting and crown.
What to do
Rule out the treatable causes early. Ferritin, thyroid and vitamin D at the six-week check and again at six months. At forty the odds of one of them being low are high.
Do not wait past twelve months. A follicle that has been quiet for six months is easier to restart than one quiet for two years, and at forty the hormonal tailwind that helps a 28-year-old’s follicles restart on their own is not there. The follicle-level approach is the one that works regardless of the hormonal weather, and it is the one to start.
Have the HRT conversation on your own timeline. Most GPs will not consider HRT under 45 without symptoms, but a woman of 42 with irregular cycles, poor sleep, mood change and thinning hair has symptoms. What it does for hair, and which progestogen.
Protect the sleep. The recovery at forty depends on it more than at any other age. What helps.
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