Sheikh Salman al-Oadah
Failure to bleed on the first night is not a sign of loss of virginity, nor is it recognized as such in Islamic Law.
There are numerous reasons why a woman might not bleed. A percentage of women do not bleed at all. Some women bleed ever so slightly that it avoids detection. Other women have had the most minor of childhood accidents or falls that broke the hymen and causes them not to bleed in maturity, and they may not even aware that such an accident had taken place. Even lifting a heavy object, running, or jumping can cause it to break. Some girls break it through touching themselves.
For some women, the hymen does not break until childbirth.
We need to know that chastity and purity are character traits that exist quite independently of the hymen’s presence or absence.
Allah describes believing women as follows: “So the righteous women are the obedient, guarding in secret that which Allah has guarded.” [Sûrah al-Nisâ’: 34]
Source: Islam Today