A late period is usually the first sign of pregnancy. Under certain circumstances, this can really be misleading because many factors can disrupt the menstrual cycle. With a regular cycle, late menstruation is defined as when it does not occur within 3 to 5 days after the expected date. A delay of 1 or 2 days cannot be considered a delay in menstruation, since ovarian cycles depend on subtle mechanisms. With an irregular cycle, it is more difficult to detect the delay of menstruation. A week late can be considered a late period. Other Causes of Late Menstruation Delayed periods can be misleading because other causes can lead to delayed ovulation and therefore delayed periods in the absence of pregnancy. The control systems of the hypothalamus-pituitary-ovary axis, at the beginning of the secretion of the key hormones of ovarian cycles – LH and FSH, are really fragile and many factors can disrupt them: Period of strong stress, emotional shock; Eating disorder, especially anorexia; Intense physical exertion; Excessive consumption of alcohol, drugs or other substances; Change in lifestyle – relocation, travel, climate change and others; Taking certain medicines and herbs; It should also be noted that after stopping contraceptives, it may take some time for cycles to become regular again due to a change in the function of the ovaries, which are at rest during contraception. If the delay in menstruation occurs only for one cycle, and then the cycles return to their regular nature, this is not a sign of pathological changes. A few days delay in menstruation can occur in the absence of pregnancy and without the presence of concomitant diseases. Restoration of the cycle, despite all symptoms of pregnancy Restoration of menstruation after a positive pregnancy test and in the presence of all signs of pregnancy may correspond to bleeding, which can be both benign – bleeding during implantation, a small decidual hematoma and others. as well as a sign of a complicated pregnancy – spontaneous abortion or ectopic pregnancy. In any case, it is recommended to consult a specialist quickly. Late menstruation with severe abdominal or pelvic pain may be due to an ectopic pregnancy – the egg has implanted outside the uterus, which may require emergency surgery and consultation with a specialist. References: https://www.passeportsante.net/famille/projet-enfant?doc=retard-regles-grossesse