Anu: Guruji pranaam kya menstrual cycle m pooja or koi bhi dharmic kaam women kar sakti h kya menstrual cycle k time pooja karne, mandir jane par girls ko koi paap lagta h kya?
Swami Ramswarup: My blessings to you, my daughter.

In this regard, I paste my article below:-

Menstrual cycle

God has given knowledge of four Vedas to the souls which reside in human body. God has not given the knowledge to bodies. Soul realizes God and attains salvation and not bodies. Soul is unchangeable and immortal whereas bodies are changeable and are destroyed. So souls either in the body of man or woman is entitled to chant all the mantras, to listen preach and to worship God. According to Yajurveda mantra 31/11 there is no any caste system except humanity based on good or bad qualities.

Almighty God is the purest matter in the universe. You see God is omnipresent therefore also is present in our stomach, stool, urine, blood, etc., but no any matter is able to touch Him. He (God) thus always remains the purest. So woman can continue her daily hawan also.

Anu: Guruji pranaam god k according paap aur punay kya hai?
Swami Ramswarup: My blessings to you, my daughter. Beti, karmon kee philosophy bahut gambheer aur vistaar mein hai, lengthy hai, jaise mata-pita, guru, buzurgon kee sewa karna punnya hai,sewa na karna paap hai. Shadi se pehle opposite sex ko dil dena ya sparsh karna paap hai aur brahmacharya rakhna punnya hai. Satya bolna punnya hai aur jhoot bolna paap hai. Alasya tyag kartavya nibhana, mehnat kee kamai karna athwa vidyarthi ka mehnat se padai karna punnya hai, na karna paap hai. Kaam, krodh, mad, lobh tyagna punnya hai etc., aur vishyon mein ramann karna paap hai, itiyadi. Parantu aslee baat yeh hai ki Ishwar ne hamein manushya ka shareer kisi vidwaan kee sharann mein jaakar ved sunne ke liye diya hai. vedon mein jo-jo shubh karma karne ko kahe gaye hain who- woh shubh karma karna punnya hai aur uske khilaf karma karna paap hai isliye sahi maayne mein to paap-punnya ka pata vedadhyayan karne ke baad hee maalum hota hai. Isliye kaha hai ki karma ki philosophy gahan aur gambhir hai kyunki aam admi Ishwareeya Vanni Ved sunna hee nahi chahta isliye paap ko bhi punnya maan kar paapi banaa rehta hai aur dukh uthata hai.