Levonorgestrel is the well-travelled aunt of the progestin world. As one of the most commonly-used progestogens in contraception, Levonorgestrel is found in combined pills, progestogen-only/mini pills (POP), the hormonal coil (IUS) and the Morning After Pill. 

The reason Levonorgestrel gets around so much is that it’s a relatively old synthetic progestin, developed when there were fewer options on the market. It belongs to the second-generation class of progestins, which were derived from testosterone. 

How does it work?

When taken as the morning after pill, Levonorgestrel is thought to work by preventing ovulation if it hasn’t already occurred. When taken as a longer-term contraceptive orally or in an intrauterine device (hormonal coil), it can also prevent ovulation and stop sperm from getting to your uterus by thickening your cervical fluid. It can also make the lining of your womb thicker, making it trickier for a fertilised egg to implant.

What it is used in?

Levonorgestrel is found in the following brands: 

Combined pills

Progestogen-only pills

Hormonal coil (IUS)

Morning after pill 

Is it androgenic?

Yes1.

What are the side effects?

Depending on how women take Levonorgestrel, side effects can vary. If it’s taken in the form of a combined pill, where other hormones are also present, it’s not possible to identify which side effects it is directly responsible for.

The following side effects have been noted2

With intrauterine use (hormonal coil)

With oral use

Breast cancer risk

Research has found a small increase in the risk of breast cancer for women who use the progestogen-only pill, or who have used it in the past. However, there is some evidence to suggest that this might be linked to an earlier diagnosis of breast cancer being more likely in progestogen-only users. There is no evidence of an increase in breast cancer risk for people who use the hormonal coil.

References

  1. Stankzyk FZ. All progestins are not created equal. Steroids. 2003. Volume 68, Issues 10–13. P879-890. Available from: https://doi.org/10.1016/j.steroids.2003.08.003 
  2. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press <https://bnf.nice.org.uk/drug/levonorgestrel.html> [Accessed on [13 August 2020]]

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