Everything you need to know about postpartum hair loss.

The exact causes of postpartum hair loss are still poorly understood today because they are under-researched. However, it is accepted that the various hormonal fluctuations occurring in the body during pregnancy are the cause of this hair fall. Thus, the increase in levels ofoestrogen and progesterone in pregnant women often results in a slight stimulation of the anagen phase of the hair cycle, which corresponds to the growth phase of the hair. Indeed, it seems that oestrogens are capable of binding to certain receptors present in the scalp, which have an affinity for this hormone and induce an acceleration of the anagen phase.

Progesterone, on the other hand, is believed to be responsible for theinhibition of the activity of 5-alpha reductase, an enzyme that modulates the conversion of testosterone into dihydrotestosterone (DHT). Indeed, DHT acts on hair follicles by shortening the lifespan of hair and accelerating hair cycles. Therefore, progesterone has a beneficial effect on hair growth.

Following childbirth, levels of oestrogen and progesterone decrease, as do the benefits they provided to the hair. Consequently, hair begins to fall out, as if to catch up on the delay accumulated during pregnancy. Indeed, some researchers have noted a slight intensification of the telogen phase after childbirth, the phase corresponding to hair loss. This would thus compensate for the "excessive" hair growth that occurs during pregnancy.

While hair loss can be concerning, it's important to remember that this phenomenon is temporary and is not harmful to the hair in the long term. To limit it, it is possible to adopt certain simple habits daily.

• A gentle brushing.

  Firstly, it is recommended to gently brush your hair, without pulling, to avoid causing additional hair loss. If you tie your hair up, it is better to opt for loose hairstyles, so as not to exert too much pressure on the hair fibres.

• The application of fortifying serums.

  Some cosmetic treatments, applied directly to the scalp, claim to have strengthening properties and a preventative action against hair loss. They are often formulated withcastor oil (INCI: Ricinus Communis Seed Oil) or biotin, a vitamin. However, scientific literature only attributes them with limited effectiveness.

• The intake of dietary supplements.

  Some dietary supplements containing cysteine or biotin are designed to prevent hair loss. A course typically lasts about 3 months. However, it's worth noting that a recent study on the effectiveness of biotin on alopecia concluded that this vitamin was only minimally effective.