Hormonal imbalances can also lead to the development of thread veins. Women going through the menopause, having a negative reaction to the Contraceptive Pill or suffering from Polycystic Ovary Syndrome (PCOS) are all more likely to develop the condition. Pregnancy is also a big cause of thread veins, due to the combination of fluctuating hormone levels and an increased amount of blood in the body.
Other common causes include environmental factors such as overexposure to the sun or to particularly cold weather. This is while being obese can lead to unusually high blood pressure, and therefore to the blood vessels rupturing more easily. Smoking and too much alcohol consumption can also lead to thread veins, as both activities lead to having unusually high blood pressure.