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Once you’ve decided that you want to become pregnant, you may feel both excitement and uncertainty. You may have concerns about your ability to conceive, especially if you experience unpredictable or irregular menstrual cycles. Some amount of variation is common—equipping yourself with information about your body and how conception works can help you make a plan and find your path to parenthood.
How do I know if I have an “irregular” cycle?
A note from the Clue Science team: Healthcare providers use terms like “abnormal” and “irregular” to describe variations from the normal that extend beyond certain established clinical parameters (1). Since the word “normal” can make people feel “abnormal” and the meaning of “normal” varies over time and across different cultures, we choose to use other words like “typical” and “unpredictable” instead.
The length of a menstrual cycle is counted from the first day of a period to the day before the start of the next period. For adults not on any form of hormonal birth control or IUD, cycle lengths between 24 and 38 days are considered typical (1). Some people will have cycles that are consistently shorter or longer than this range.
Even the same person will have variation in the number of days from cycle to cycle (2). If you’ve been tracking your cycles, you can subtract your shortest cycle from your longest cycle to determine the variation, or look at the Analysis Tab in the Clue app. If it’s nine days or less, this is an expected level of variation (1). So, for example, if your last menstrual cycle was 29 days long, and the one before was 38 days long, this falls into a typical range.
What causes unpredictable periods?
Most unpredictable cycles are caused by inconsistent ovulation, when eggs are not released on the same cycle day, or might not be released at all during some cycles. Some reasons for inconsistent ovulation include:
Reproductive life stage (3)
Recent use of hormonal birth control
Health conditions (4,5)
Life factors (6-8)
Working night shifts
If your cycle is unpredictable, your individual path to conception will depend on the cause.
How do unpredictable cycles impact conception?
The peak days for conception include the five days leading up to ovulation and the day of ovulation. During this time, it’s possible to become pregnant from either having penis-in-vagina sex (referred to as “sex” in this article) without birth control, or through other forms of insemination such as intracervical or intrauterine insemination (ICI and IUI) (9).
The highest likelihood of pregnancy is from sex that occurs in the two days leading up to ovulation (10). For people with unpredictable cycles, ovulation may be inconsistent, but even people with predictable cycles can have variation in the peak days for conception (9,10).
When you want to become pregnant, timing sex in the days leading up to ovulation may help increase your odds of becoming pregnant (11). This is why trying to predict ovulation is helpful.
Can I track ovulation if I have an unpredictable cycle?
Tracking your cycles can help you identify patterns of what is normal for you. And while highly unpredictable cycles can make it harder to accurately predict ovulation, it is possible with some tools and practice.
Clue’s new mode Clue Conceive was built especially to help you track to know when’s best to conceive without the use of any other tools. By tracking the first day of your period, Clue Conceive’s state-of-the-art algorithm can predict on which days you are most likely to get pregnant. The more cycles you track, the more accurate the predictions become. If you are trying to become pregnant, having sex every day or every other day during these days can increase your chance of conception (12-14).
Adding in other indicators of ovulation may give you more confidence in the prediction of which days you are most likely to conceive and give you a more precise estimate of ovulation.
Even if you don’t become pregnant by tracking your period and monitoring for signs of ovulation on your own, the information that you gather will help you and your healthcare provider make a plan.
If your period is unpredictable–and particularly if this is a new change–seeking guidance from a healthcare provider could be valuable in identifying and treating any underlying health conditions and making a plan for becoming pregnant.
Get Clue Plus to access the new Clue Conceive mode in-app. Clue Conceive provides personalized predictions for fertile days that can help you time sex or home insemination to conceive faster, based on clinically-tested technology. Find out more here.