What does it mean if you have a late period but you’re getting negative pregnancy tests? It means that your period isn’t actually late—you probably just ovulated late. Without tracking your cycle, it’s impossible to know when to take a pregnancy test.
Is Your Cycle Always Regular?
Some women have irregular cycles and are never really sure when to expect their periods. Other women have very regular cycles; their periods always seem to come at predictable intervals1.
If your cycle length is usually pretty consistent, it can be very alarming when your period is late. But your body is not a machine, and regular cycles in the past does not guarantee regular cycles in the future.
How to Never Be Surprised by a Negative Pregnancy Test
The menstrual cycle is broken down into two phases. The follicular phase begins on the first day of your period and ends when you ovulate. The luteal phase begins after ovulation and ends when you get your next period.
During ovulation, an egg bursts out of a follicle in your ovary. The spent follicle transforms into something called a corpus luteum, a temporary structure that secretes progesterone. The progesterone helps thicken your uterine lining. After about two weeks, the corpus luteum runs out of progesterone, your uterine lining can no longer be sustained, and it sheds during your period.
The luteal phase ranges from 10 – 16 days, but it doesn’t vary much in individual women. If your luteal phase is usually 12 days, it may occasionally be 11 or 13 days, but it will probably never be 16 days2.
The follicular phase, on the other hand, can be sensitive to physiological stress. Things like travel, stress, illness, and changes in diet and exercise can cause you to ovulate later than normal. Since the length of the luteal phase is usually fixed, a longer follicular phase will mean that your period arrives later than normal—but it will still be the same number of days after ovulation.
Put it into Practice
For example: Jessica usually has a 30-day cycle. Because she tracks everything, she knows that she usually ovulates around cycle day 17, and she usually has a 13-day luteal phase. This month, she traveled to Fiji for her honeymoon around day 10 of her cycle. She didn’t feel stressed—she was having the time of her life!—but the jet lag caused some stress on her body. It was enough to delay her usual ovulation by almost two weeks, so that she didn’t ovulate until she got back from her trip, on CD30. When her period didn’t show, she wasn’t concerned at all, because she knew it wasn’t supposed to show up 13 days after she ovulated. And on CD43, it came right on time.
Bottom line: when your period comes depends on when you ovulate and how long your luteal phase is.
- If you recently came off birth control pills, you might be used to very regular cycles. But your natural cycle length might be very different from the artificial cycle length you had while on the Pill. ↩
- There is an important exception to the standard-length luteal phase rule: certain factors, including breastfeeding, pre-menopause, calorie restriction, and intense exercise, may shorten the luteal phase. ↩