Oestrogen and progesterone are the primary sex hormones in females, playing powerful roles throughout life – from puberty and periods to pregnancy and eventually menopause.

During adolescence, these hormones surge, kick-starting the menstrual cycle. In adulthood, they fluctuate month to month, driving ovulation and menstruation. But between the ages of 45 and 55, their levels start to decline.

This signals the beginning of perimenopause – the transitional phase leading to menopause, which is officially marked when a woman has gone 12 consecutive months without a period. After that, hormone levels settle at a lower, steady baseline, ushering in the postmenopausal stage.