The European Medicines Agency says it has started a review of cervical cancer vaccines to see if they are linked to two rare conditions, but emphasized it hasn't changed its recommendations for how the shots should be used.

The vaccines against HPV have been used in more than 70 million people worldwide and prevent cancers caused by HPV, including those of the cervix and womb.

In a statement issued on Monday, the European drug regulator said an investigation has started into a possible connection between the HPV vaccines and two conditions: complex regional pain syndrome, and POTS, a condition where the heart rate jumps abnormally after sitting or standing.

Current HPV vaccine information doesn't include warnings about these conditions and no causal link has been found.