Bladder weakness can have a number of different causes:

Weakened pelvic floor muscles – the pelvic floor muscles support the organs in the pelvis and abdominal cavity, especially when a person is standing up or exerting themselves. They also support the bladder and help it to stay closed. When these muscles lose their strength and flexibility, everyday activities such as coughing, laughing or jumping may cause a small amount of urine to escape. Pelvic floor muscles can be stretched and weakened during childbirth. Being overweight may put added strain on these muscles

Menopause – the levels of hormones in the body, which normally keep the bladder healthy, reduce after the menopause and often cause bladder weakness in women

Enlarged prostate (benign prostatic hyperplasia or BPH) – as the male prostate gland expands, it wraps itself around the neck of the bladder like a collar, restricting the outlet and placing pressure on the bladder and urethra. This can affect the passing of urine, making it difficult to start urinating, causing a frequent need to urinate or difficulty fully emptying the bladder

Other causes may include: damage to the nerves; cystic fibrosis; certain drugs, including diuretics such as caffeine; constipation, or even an infection. Type 2 diabetes can also cause bladder problems.