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Why is my period late?

Approved by our Clinical team | Apr 03, 2020

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Variation in your menstrual cycle is completely normal, especially if you have just started getting your period, are breastfeeding or nearing the menopause. There are lots of reasons for a late period; lifestyle factors such as stress and diet can affect your cycle.

The medication you're on or a new contraceptive can influence the length of your period and the length of your cycle, so you may experience a delayed period from time to time. Many women have irregular periods; the date they start can change as well as how long they last and how heavy they are.

Reasons for a late period can include:

Sudden weight loss – restricting your calorie intact can stop your body producing the hormone it needs for ovulation.
Being overweight or obese – your body may produce an excessive amount of oestrogen and this can affect your periods.
Excessive exercise – losing too much body fat through excessive exercise can stop you ovulating and the stress of the physical activity can affect the hormone levels in your body.
Stress – feelings of stress and anxiety can affect your menstrual cycle making it longer or shorter or your periods may stop all together.
Illness – being ill and the extra stress that this puts on your body could mean that your period is delayed.
Changing your contraception – Your body may take some time to regulate itself. Contraceptives like the implant can stop your periods completely, or you might find that they become irregular.
Taking the contraceptive pill – many pills can cause your periods to stop completely or you might miss a pill every so often when taking the contraceptive pill.
Polycystic ovary syndrome (POCS) – this common condition affects how women’s ovaries work resulting in irregular and late periods or you may have no period at all.
Pregnancy – If your period is late, you are sexually active and have had sex without using contraceptive or it has failed you might be pregnant. If you think that you might be pregnant you can purchase a pregnancy test to complete in the privacy of your own home, visit your GP or your local sexual health clinic to get tested.
Beginning the menopause – you might find that you are missing periods or that they are late. As the levels of oestrogen in your body decrease your menstrual cycle will change. In time your periods will stop completely.
Breastfeeding – If you’re breastfeeding you might not have a period, this is because the hormones responsible for milk production also supresses ovulation.

If you have experienced any of the above causes of a late or missed period then you can visit your GP, a nurse at your local sexual health clinic or chat to one of our expert Pharmacists in your nearest store to find out more and get any advice that you might need.

How late can a period be?

Your cycle can vary from month to month by about 7-9 days, this is considered completely normal for women and this variation doesn’t necessarily mean that your period is late or that you have missed a period. If you have irregular periods it can be harder to tell if your period is late, it’s important to bear in mind that women can experience menstrual cycles that range from 21 days to 40 days.

Can I track my period?

Every woman is different and plotting out your menstrual cycle is a great way to figure out what the average length of your cycle is for you. Once you have plotted when you should start your period you’ll know what to consider to be a late or a missed period. It's common to have a period which is 2-3 days late as your cycle can fluctuate from time to time.

For many women a period is considered late if it hasn’t started five or more days after the date you expected it to start. If you period is over 4-5 days later then you usually expect, you may want to seek advice or take a pregnancy test for your own peace of mind.

What are the signs that I will be starting my period?

One to two weeks before you start your period you may notice certain psychical, emotional and behavioural changes taking place. Many women notice that they are feeling tired, irritable and crave certain foods.

How will I know if I'm pregnant?

For women who have a regular menstrual cycle the first sign that you are pregnant is a missed period, however some women will notice that their period is very light compared to normal. If you have missed a period you can purchase a pregnancy test to complete in the privacy of your own home, visit your GP or your local sexual health clinic.

What is the menopause?

The menopause is when you have no periods and you will not be able to get pregnant naturally. This happens to women in their late forties to mid-fifties. Many women will notice that their periods completely stop, however others will see their periods become less frequents in the years and months leading up to the menopause.