Australia's government-funded health service, healthdirect, says menstrual cycles typically range from 21 to 35 days. Jean Hailes for Women's Health adds a detail many people don't expect: being unwell, travel and major changes to your routine can all throw a cycle off.
That means a period that's later than usual isn't automatically a pregnancy question. Here are six reasons your period might be late, drawn from Australian health sources, plus the signs that mean it's time to see a GP.
Quick answer: Besides pregnancy, a period can run late because of stress or anxiety, being unwell, travel or a big change in routine, sudden weight loss or gain, too much or too little exercise, starting or changing hormonal contraception, or conditions like PCOS and thyroid problems. If you could be pregnant, take a test first.
Why is my period late if I'm not pregnant?
According to healthdirect's irregular periods page and Jean Hailes' guide to periods, these are the most common culprits:
- Stress and anxiety. Both sources list stress, and Jean Hailes specifically mentions high stress or anxiety.
- Being unwell. Jean Hailes includes being unwell among the health factors that can lead to missed or irregular periods.
- Travel or a new routine. A long trip, shift changes or another major shake-up to your routine is on the Jean Hailes list too.
- Weight changes. healthdirect names sudden weight loss or gain, and Jean Hailes lists being overweight and eating disorders such as anorexia nervosa.
- Exercise levels. healthdirect mentions lack of exercise, while Jean Hailes points to excessive exercise, so both extremes can play a part.
- Contraception, medicines and health conditions. Starting or changing hormonal contraception can alter your cycle, as can copper IUDs and some other medicines. PCOS, premature ovarian insufficiency and thyroid problems are medical causes worth ruling out.
Life stages matter as well: healthdirect says irregular periods are common when periods first start, after childbirth and during perimenopause. For more on the mind-body side, read our article on whether stress can affect your period.
Can being sick delay your period?
It can. Jean Hailes lists being unwell alongside stress and routine changes as things that can cause missed or irregular periods. If you've had a rough fortnight with a virus, a later period may simply be part of your body catching up. If it doesn't arrive over the following months, book in with your GP.
What counts as a missed period in Australia?
healthdirect doesn't set a number of days that makes a period "late". Instead, it suggests seeing a doctor if you've had no period for three months or more, or if you have eight or fewer periods in a year. Until then, a cycle that stays within roughly 21 to 35 days is considered typical.
When to see a GP
- No period for three months or more.
- Eight or fewer periods in a year.
- No period by the age of 16.
- Bleeding between periods or after sex.
- Periods that last longer than seven days.
- Irregular periods along with weight gain, tiredness or difficulty falling pregnant.
- Periods that are heavy, painful or absent, according to Jean Hailes.
Frequently asked questions
Can travel make my period late?
Yes, it can. Jean Hailes lists travel and major routine changes among the lifestyle factors that can lead to missed or irregular periods. A long-haul flight, a new time zone or a run of night shifts may be enough to shift things. If your period hasn't returned within three months, healthdirect recommends seeing a doctor.
Is it normal for my cycle length to change?
Some variation is common. healthdirect says cycles typically range from 21 to 35 days, and irregular periods are common in the first years after periods start, after having a baby and during perimenopause. A GP visit makes sense if you get eight or fewer periods a year or go three months without one.
Can changing my pill delay my period?
It can. healthdirect lists starting or changing hormonal contraception as a lifestyle cause of irregular periods, and Jean Hailes notes copper IUDs and some other medicines can affect your cycle too. If your bleeding pattern changes after a switch, your GP or pharmacist can tell you what's expected for that method.
Whether your period turns up on time or keeps you guessing, it helps to have something ready. The Lunette period cup is a reusable menstrual cup made in Finland from 100% medical-grade silicone, and it lasts up to 10 years with proper care. Check our size guide to find your fit.
This article offers general information only and isn't medical advice. For health questions, speak with your GP or call healthdirect on 1800 022 222. In an emergency, call triple zero (000).
