Subgroup analysesSubgroup analyses by dose of BHT suggested that higher doses of BHT may be associated with more effectiveness but also higher risk of adverse effects .
There was low to moderate quality evidence that BHT in various forms and doses is more effective than placebo for treating moderate to severe menopausal hot flushes .
There was some evidence to suggest that higher doses of BHT are associated with greater effectiveness but also with higher risk of adverse effects .
No data are yet available about the safety of BHT with regard to long-term outcomes such as heart attack , stroke and breast cancer .
BACKGROUND Various hormone therapies ( HT ) are available to treat  menopausal vasomotor symptoms .
Bioidentical hormones are chemically identical to those produced by the human body , and several types are well-tested and available on prescription .
Many women have opted for bioidentical hormone therapy ( BHT ) on the assumption that it is safer than other forms of HT .
We evaluated the evidence .
OBJECTIVES To determine the effectiveness and safety of bioidentical hormones compared to placebo or non-bioidentical hormones for the relief of vasomotor symptoms .
Estradiol and the addition of progesterone increase the sensitivity to a neurosteroid in postmenopausal women
The aim of this study was to compare the pharmacodynamic response to a neuroactive steroid , pregnanolone , before and during different hormonal setting s of postmenopausal hormone replacement therapy ( HRT ) , using natural progesterone . A second aim was to investigate whether the response to pregnanolone was associated with cyclicity in negative mood symptoms during treatment . Twenty six postmenopausal women with climacteric symptoms were administered HRT in a r and omized , double blinded , placebo-controlled , crossover study . The women received 2 mg oral estradiol ( E(2 ) ) continuously during two 28-day cycles and 800 mg of vaginal progesterone or placebo sequentially for the last 14 days of each treatment cycle . Pharmacodynamic response to pregnanolone was assessed before treatment , and during the last week of each treatment cycle , by comparing the effects of intravenous pregnanolone ( 3alpha-hydroxy-5beta-pregnan-20-one ) on saccadic eye velocity ( SEV ) , saccade acceleration , saccade latency and self-rated sedation . Throughout the study daily symptom rating scales were kept . According to the daily symptom rating scales , patients were divided into two groups ; one group who displayed a significant variance in negative mood symptoms during HRT ( cyclicity ) and one group with no cyclical changes in negative mood symptoms during treatment . During treatment with either E(2 ) alone or E(2)+progesterone the response in saccadic eye movement parameters and in self-rated sedation to pregnanolone was enhanced compared to pretreatment values . The SEV , saccade acceleration and sedation responses to pregnanolone was also increased in women expressing cyclicity in negative mood symptoms compared to women with no cyclical changes in negative mood during HRT . In conclusion , during treatment with either E(2 ) alone , or E(2)+progesterone , pregnanolone  sensitivity was increased . Women expressing cyclicity in negative mood symptoms were more sensitive to pregnanolone than women without symptom cyclicity during HRT
Subgroup analysesSubgroup analyses by dose of BHT suggested that higher doses of BHT may be associated with more effectiveness but also higher risk of adverse effects .
There was low to moderate quality evidence that BHT in various forms and doses is more effective than placebo for treating moderate to severe menopausal hot flushes .
There was some evidence to suggest that higher doses of BHT are associated with greater effectiveness but also with higher risk of adverse effects .
No data are yet available about the safety of BHT with regard to long-term outcomes such as heart attack , stroke and breast cancer .
BACKGROUND Various hormone therapies ( HT ) are available to treat  menopausal vasomotor symptoms .
Bioidentical hormones are chemically identical to those produced by the human body , and several types are well-tested and available on prescription .
Many women have opted for bioidentical hormone therapy ( BHT ) on the assumption that it is safer than other forms of HT .
We evaluated the evidence .
OBJECTIVES To determine the effectiveness and safety of bioidentical hormones compared to placebo or non-bioidentical hormones for the relief of vasomotor symptoms .