en Sports and Exercise Medicine Sports and Exercise Medicine Original Research Original Research <p align="left" style="margin: 0px -29px 0px 0px; text-align: left; line-height: 200%;"><strong>Background: </strong>Functional hypothalamic menstrual disorder (FHMD) has a destructive effect on the athlete&rsquo;s bone mineral density and cardiovascular system. Utilizing hormone replacement therapy to treat FHMD in athletes is controversial.<br> This study was conducted to examine the effect of hormone therapy on bone density and the cardiovascular system of professional female athletes with FHMD.<br> <strong>Methods:</strong> In this study, 18 female athletes with at least a 2- year history of FHMD were recruited in a 9-month single blind randomized clinical intervention (RCT) and randomly classified into 2 groups: the oral contraceptive pills (OCP) group, who received a low-dose combined oral contraceptive (OC) containing 30 &micro;g ethinyl estradiol and 150 &micro;g levonorgestrel (n= 10), and the control group (n = 8). Bone mineral densitometry (BMD) and certain cardiovascular risk factors were measured before and after the 9-month trial. The Chi square test was used to compare the quantitative and qualitative results.<br> <strong>Results: </strong>Bone mineral density did not change significantly in either group. Very low density lipoprotein (VLDL) (p= 0.035) and Apolipoprotein B (Apo B) (p= 0.04) reduced significantly in the OCP group. An increase was observed in the serum levels of Apolipoprotein A (Apo A) (p= 0.01) in the control group. Changes in the Apo B to Apo A ratio was significant in both groups (OCP group: p= 0.018, control group: p= 0.040). No significant changes were observed in the other measured factors.<br> <strong>Conclusion: </strong>Although the administration of estrogen did not significantly increase bone mineral density, it had positive effects on the cardiovascular system and lipid profile.<br> &nbsp;</p> <p align="left"></p><p align="left"></p><p align="left"></p> Functional hypothalamic menstrual disorder (FHMD), Hypoestrogenism, Bone density, Cardiovascular risk factor, Hormone therapy, OCP (oral contraceptive pills) 151 157 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1121-1&slc_lang=en&sid=1 Haleh Dadgostar hldadgostar@gmail.com 200319475328460037472 200319475328460037472 No Department of Sports and Exercise Medicine, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran. Ghazaleh Soleimany hldadgostar@gmail.com 200319475328460037473 200319475328460037473 Yes Department of Sports and Exercise Medicine, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran. Shafieh Movaseghi movaseghi@gmail.com 200319475328460037474 200319475328460037474 No Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Elham Dadgostar edadgostar@gmail.com 200319475328460037475 200319475328460037475 No Sports Medicine Federation of Islamic Republic of Iran, Tehran, Iran. Sara Lotfian saralotfiyan@yahoo.com 200319475328460037476 200319475328460037476 No Department of Sports and Exercise Medicine, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.