‘The pill will make me fat’….and other contraceptive pill concerns

By: Dr Natalie Hutchins

Star Vista clinic
Posted on: 9 Oct 2023

“I will gain weight”

This sadly tends to be a very widely held fear, especially amongst young women and teens, but the evidence shows that this isn’t true. It’s such a shame that it makes some think twice about taking the pill* as this group are often the ones for whom it could work well; not just for contraception but for managing period problems and acne too. There are many anecdotal stories out there that claim the opposite, so I appreciate it may be difficult to believe, but in the 4 placebo-controlled trials published to date (hopefully there will be more in the future) there was no difference in weight gain.

Of course, that doesn’t mean you won’t ever put on weight whilst you’re on the pill, but it isn’t because of the pill. The culprit is more likely to be the lifestyle changes that are often associated with starting it in the first place: settling down with a partner or perhaps moving to university, having to cook (or not) for yourself, drinking more and sleeping less. Most of us would have some weight gain over time if we weren’t mindful of these factors.

The one small caveat to that is that whilst studies show you won’t put on weight, there are definitely some women who are sensitive to oestrogen’s water retention effect, meaning they may feel less comfortable in their clothes with some pills. This shouldn’t be a reason to rule the pill out completely if you think it would otherwise work well for you. There are many different brands of combined pill, each with a slightly different hormone profile, so if water retention is a concern, we might try one with a lower dose of oestrogen or a different type of progesterone that acts as a diuretic. It’s not uncommon for some women to try a few different types before they find the one that really suits them.

“It will affect my future fertility”

No, it won’t. The vast majority of women using the pill for contraception become pregnant in the 1st year after stopping it and half of those women will do so within 3 months (so if you’re thinking about becoming pregnant but aren’t quite ready for it to happen immediately, do bear this in mind). The pregnancy rates at 1 year of trying to conceive are the same in women that have recently stopped the pill compared to those who haven’t been on it or have been using condoms, although there is a small delay of a few months in conceiving for the women that were on the pill compared to women that weren’t.

There is also no evidence that the longer you use the pill, the worse your fertility will be afterwards, in fact some studies have shown the opposite is true.

For the very small number of women that struggle to conceive having been on the pill for a long time, the cause might be related to the reason they started taking the pill in the first place. For example, some people with irregular periods may go onto the pill to regulate their cycle, but as their underlying diagnosis is actually PCOS (more on this in another post), when they stop the pill their periods do not return. Or they may have had painful and heavy periods, which have been helped by the pill, but they actually have underlying endometriosis, which may affect their fertility when they start trying to conceive, not the pill itself.

“It will give me breast cancer”

The short answer to this is that current and recent use of the pill is associated with a small increase in breast cancer but that risk is very small in most women under 50. If we imagine a stadium filled with 100,000 women aged 15-49yrs that had never used the pill, (the Singapore national stadium fits just over half of that, so think of that filled to the brim and double it) 55 of them would get breast cancer (0.056%). In the same stadium filled with the same number of women that were currently using or had recently used the pill, that number would be 68. An increase, yes, but a small one that reduces after you stop the pill so that by 5 years after stopping, your risk is the same as for other women your age.

The longer answer is that balancing individual risk can be complicated because we also have to take into account other factors such as your alcohol intake, your weight, whether you smoke, your family history and importantly the emotions that may come with that. If you have watched a close family member struggle with breast cancer, even if it wasn’t part of an inherited cancer syndrome, you may feel that any additional risk, no matter how small, is too much. And if that leads you to conclude that the pill just isn’t right for you, that is fine, there are many other options.

In essence though, I think if your only worry with the pill is cancer and you are under 35 and don’t have an otherwise concerning history, the additional impact of the pill on your breast cancer risk is so small, that it is probably outweighed by the potential benefits.

“I have to have the traditional pill free break to have a bleed every month”

I think this is one of the best things about the pill for younger women: the ability to control when and if you have a period. There is absolutely no medical need to have the withdrawal bleed (this is what we call the period you get when you finish a pill packet and is different from a natural period). Many women take their pill packets continuously and this will cause you no harm (although sometimes it can cause some spotting depending on which pill you are on). For some it’s a welcome relief from very painful or heavy periods and for others just a temporary hack to avoid ruining a holiday. If you’d like to try this, do ask how as some pill brands differ and require specific instructions.

* When I write “pill”, I am referring to the combined contraceptive pill but the information above is also relevant for other forms of combined hormonal contraception (with oestrogen and progesterone) such as the vaginal ring or patch.

Dr Natalie Hutchins is a British GP family doctor with a history in obstetrics and gynaecology, giving her deep experience into women’s health concerns. Dr Natalie is located at Osler Health Star Vista clinic. For appointments please call here



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