Finding a method of contraception that works for you is rarely straightforward. Choosing between the pill, implant, injection, coil and patch is hard enough without having to navigate all the symptoms that can accompany said methods.

But even once you’ve found a method that works well, you might experience a few odd side effects or changes – as many people who use the hormonal coil find out.

Everyone’s experience with the hormonal coil is slightly different, with some people experiencing shorter or lighter periods while other people see them stop altogether. But even with the absence of bleeding, many people find that they still experience symptoms akin to a hormonal cycle throughout the month. So, why do some people on the coil still feel ‘hormonal’ during that time of the month? And how does it work? 

We put those questions – and more – to Dr Jan Toledano, a women’s hormone specialist and founder of the London Hormone Clinic. Here’s what she had to say. 

The hormonal coil works in three key ways, but its hormonal impact comes from the small amount of progestogen (a synthetic form of progesterone) that it releases throughout its lifespan. While progesterone is responsible for preparing the uterine lining for implantation in the second half of the menstrual cycle, the constant low levels of the hormone the coil provides actually keeps the womb lining thin so an egg cannot implant.

The progestogen released by the hormonal coil can also lead to a thickening of the cervical mucus, which can stop sperm from reaching an egg. 

Many people on the pill experience shorter or lighter periods, while some don’t experience bleeding at all. But why is there such a variety of different experiences?

Often, it’s because different coils deliver different doses of hormones. “For those whose periods stop, it’s often because the womb lining stays too thin to cause a bleed,” Dr Toledano says. “Sometimes it is also because the hormones in the coil are very low.” 

Women with conditions that affect the womb – like endometriosis and adenomyosis – are less likely to experience a stop in bleeding, and it’s more common to experience bleeding during the first six months following insertion or towards the end of the coil’s lifespan. 

While some types of hormonal coil can stop ovulation as well as bleeding, most people will still experience some kind of hormonal cycle while using this form of contraception.

This is because the coil only releases hormones locally in the womb, so the amount of hormones in the blood is not enough to affect the hypothalamus, which is responsible for controlling the release of hormones involved in the menstrual cycle, like oestrogen and gonadotropin-releasing hormone (GnRH). 

“Some women on the hormonal coil experience a suppression of their hormones,” Dr Toledano explains. “It’s called hypothalamic suppression, and it’s a bit like being on the pill but without the replacement of hormones that the pill provides.”

Other people might experience hormonal symptoms while on the coil – such as depression, weight gain and headaches – because they cannot tolerate the synthetic progestogen that it provides, Dr Toledano adds. 

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