Hair loss in women: why the assessment comes before treatment

Hair loss in women: the most common form

In adult women, the main cause is female androgenetic alopecia, also called female pattern hair loss. The hair gradually thins on the top of the head, around the parting, while the hairline at the front is usually preserved. The loss happens through progressive thinning rather than sudden shedding.

It is common: according to the European guideline, it affects up to 42% of women, and its frequency increases with age. It often starts during the reproductive years, with a second peak around the menopause.

Several causes can add up

In the same woman, several mechanisms often combine: mild androgenetic alopecia, reactive shedding after childbirth, an illness or a diet, a deficiency, a thyroid disorder. Looking for these associated causes can improve the response to treatment.

Iron deficiency is the most common nutritional deficiency in the world. Before the menopause, periods and pregnancies are its main causes. Its direct link with hair loss is still debated, and there is not enough evidence to test every woman for it systematically. But iron deficiency anaemia must be treated: the question is therefore worth asking at every assessment.

The thyroid is the other thing to check: a disorder can sustain hair loss and slow regrowth.

The signs I look for

Part of the assessment is done through questions and examination. Some signs prompt a search for an excess of male hormones, as in polycystic ovary syndrome:

• irregular periods or difficulty conceiving;
• persistent acne or very oily skin;
• increasing hair growth on the face or body;
• a change in the voice.

Most women who lose density, however, have no hormonal excess, and isolated loss of density with normal hormone levels is not a sign of it. I also ask about your medicines, your pregnancies and any recent diets.

A targeted blood test

There is no single test panel that suits everyone. An international recommendation regards it as essential to assess every woman concerned for a possible excess of male hormones, and considers iron, thyroid or vitamin D tests useful depending on the case. The blood test is therefore chosen according to your history and the examination.

The contraceptive pill alters some hormone levels: this is taken into account when choosing the timing of the blood test and when reading the results.

Treatment, once the cause is known

A deficiency or a thyroid disorder is corrected first. For androgenetic alopecia, the first recommended treatment is topical: a minoxidil solution applied to the scalp every day. The first effects usually take two to four months. Slightly heavier shedding during the first weeks is possible, and temporary. When it is stopped, the hair loss resumes: it is a long-term treatment.

Oral treatments exist when hair loss is significant or a hormonal excess is present. Some act on male hormones and can harm the development of a foetus: they require strict contraception. If one of them is prescribed outside the indication stated in its product information, I tell you so clearly. Scalp PRP, offered at the practice from November 2026, can be added as a complement. Progress is reviewed at six months, on photographs taken in the same conditions.

During pregnancy or breastfeeding

Most treatments should then be avoided. Minoxidil solution must not be used during pregnancy and breastfeeding, treatments acting on hormones are not an option, and PRP is postponed.

On the other hand, iron deficiency, for which pregnancy is a common cause, can be checked and corrected, and you can be reassured: marked shedding two to four months after childbirth is most often temporary, followed by full recovery. If density does not return, the assessment is resumed after breastfeeding.