Genetic influence is one of the factors determining when and how much hair loss occurs. However, one of the most common types of hair loss in women is telogen effluvium, whereby increased shedding occurs over the entire scalp (not in patches). Shedding seems noticeably increased when combing, brushing and washing. This type of diffuse hair loss may be caused by thyroid or hormonal imbalances, stress, surgery, chemotherapy, nutritional or age-related factors, or even medications being taken or underlying disease. Women who have recently given birth may also experience telogen effluvium, however, hair conditions almost always return to normal once your baby approaches his or her first birthday. Because sudden or excessive hair loss may be a symptom of illness, it is important to consult your doctor for an accurate diagnosis and treatment.