Table 2

Clinical and metabolic effects of norethisterone (NET) and norethisterone acetate (NETA)

HeadingRelative potencyRemarksReferences
Endometrium +++A potent progestogen 2 15–17
Thrombosis −/++Dose-dependent increase in the risk of thrombosis
  • No risk in doses (ie, 0.35 mg/day) used in progestogen-only contraceptive pills

  • Slightly elevated in doses (ie, 0.5–1 mg/day) used in HRT with oral estrogen

  • Significant elevation in therapeutic use (ie, 10–15 mg/day)

5 7 18 19 21 22 50
Breast +Stimulates proliferation of breast cancer cells in vitro
Cancer risk increased after 5 years’ use
Bone ++Dose-dependent increase in bone mass and density 29–32
Cardiovascular health
Lipids +Lowers HDL, but also LDL and triglycerides maintaining a beneficial ratio 34
Glucose Neutral?Paucity of data and no data on patients with type 1 and 2 diabetes 31 35 36
Body composition +Decrease in visceral adiposity, but only results concerning HRT together with estrogen component 37 38
Cognitive function and mood +/−Inconclusive results 40–43
  • HDL, high-density lipoprotein; HRT, hormone replacement therapy; LDL, low-density lipoprotein.