en Gynecology & Obstetrics Gynecology & Obstetrics Original Research Original Research <p> <strong> Background </strong>: Gestational trophoblastic neoplasia (GTN) disease is excessive and inappropriate proliferation of trophoblast after termination of the pregnancy. Many attempts have been made to improve follow-up procedures, but no studies have evaluated Human Chorionic Gonadotrophin (HCG) as a post treatment indicator. Thus we aimed to know β-HCG variability in post treatment pregnancies. </p><p> <strong> Methods: </strong>40 Molar affected pregnancies were followed post-surgical treatment by serum β-HCG level in a tertiary level hospital. All subjects were treated by evacuation and followed by β-HCG every week for three weeks, then every month for six months. </p><p> <strong> Results: </strong>30 women were normal (group I) and 10 (group II) diagnosed as GTN cases. Serum β-HCG which obtained serially shown significant differences between two groups (p=0.001). The quantity of β-HCG/week had significantly higher level than normal females ( p<0.001) </p><p> <strong> Conclusion: </strong>Our results suggested that β-HCG serum level could be used as a strong indicator for identifying affected patients at early stage. </p><p>  </p> Gestational trophoblastic neoplasia, Molar pregnancy, β-HCG, Chemotherapy. 272 275 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-674&slc_lang=en&sid=1 Soheila Aminimoghaddam dr_aminimoghaddam@yahoo.com 200319475328460012842 200319475328460012842 No Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran. Fariba Yarandi yarandi_f@yahoo.com 200319475328460012843 200319475328460012843 Yes Tehran University of Medical Sciences, Tehran, Iran. Forough Nejadsalami 200319475328460012844 200319475328460012844 No Iran University of Medical Sciences, Tehran, Iran. Farrokh Taftachi ftaftachi@yahoo.com 200319475328460012845 200319475328460012845 No Tehran University of Medical Sciences, Tehran, Iran. Fereshteh Noorbakhsh 200319475328460012846 200319475328460012846 No Iran University of Medical Sciences, Tehran, Iran. Fatemeh Mahmoudzadeh 200319475328460012847 200319475328460012847 No Mazandaran University of Medical Ssciences, Sari, Iran.