Question: 

Will the Walimah be valid if the couple were unable to be intimate due to the wife experiencing her monthly cycle? 

Answer: 

Having intercourse is not a requisite for the validity of the Walimah. Therefore, Walimah that is celebrated the day after (the newlywed couple) spend the night together is valid even though they were unable to be intimate (due to the wife experiencing her menstrual cycle.)