Medically reviewed by Katherina Shkodzik, OB-GYN, M.D.

Polycystic ovary syndrome (PCOS) is a common hormonal disorder that affects one in ten women in the UK and US. The disease impacts women’s ability to ovulate regularly which significantly decreases the ability to conceive naturally.

Although PCOS tops the list of the most common infertility causes associated with anovulation, most of the women don’t realise they have it until they start trying to conceive.

According to the NHS, the three main features of PCOS are –

  • Irregular periods, which means your ovaries do not regularly release eggs (ovulation).
  • Excess androgen – high levels of ‘male’ hormones in your body, which may cause physical signs such as excess facial or body hair.
  • Polycystic ovaries – your ovaries become enlarged and contain many fluid-filled sacs (follicles) that surround the eggs (but despite the name, you do not actually have cysts if you have PCOS).

Mira, a first numeric at-home hormone tracker, evaluated 1100 women’s hormone graphs to see what patterns distinct a cycle of a healthy woman from a cycle of a woman with PCOS.

Here are five red flags to look out for that could indicate PCOS when tracking your hormones from home.


Longer or absent cycles

Based on Mira’s research, the cycle length of women with PCOS is usually longer than healthy groups and the ovulation day of women with PCOS is often happening later. 

When women’s cycle length is greater than 35 days, this condition is called oligomenorrhea. In fact, 90% of women with oligomenorrhea have PCOS. So if you notice that your cycle is longer than usual or absent, you should consider speaking with your OBGYN about additional tests for PCOS.

Elevated LH levels

The study shows that women with PCOS had elevated LH (luteinising hormone) during the pre-ovulatory and luteal phase, but almost the same level of LH during ovulation. In healthy groups, LH increases drastically on ovulation day and falls afterwards, forming a significant spike on the hormonal chart. 

Elevated E3G levels

Women with PCOS also have elevated E3G (estradiol) levels throughout the cycle. However, both LH and E3G stay within the normal range. Having numeric hormone values at hand helps you understand if your LH and E3G levels tend to the upper bar which can be a solid sign of PCOS.

LH surge in the afternoon 

LH peak is usually associated with ovulation and occurs between cycle days 12 to 16 days in a healthy woman. In contrast, in groups with PCOS LH peak occurs at cycle day 17 to 20, even much later, and takes place in the afternoons. However, LH surge in the afternoon, according to our study, is also applied for the healthy group. 

Multiple LH peaks

According to our data analysis, hormone graphs of women with PCOS demonstrate multiple LH surges throughout the cycle. 

No increase in PdG level

PCOS is associated with ovulation disruptions. It means that most of the cycles of PCOS happen without ovulation. So, if there is no ovulation – there is no increase and detection of progesterone levels. Monitoring progesterone levels will help you understand whether ovulation has occurred. If you do not see a surge in PdG on days 6-8 days after ovulation, there was no ovulation, which causes suspicion of PCOS.

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