A missed or late menstrual period often leads to questions about pregnancy. This article clarifies what constitutes a “late” period, when to take a pregnancy test, and other reasons for a delayed period.
Understanding a “Late” Period
The menstrual cycle length varies, typically ranging from 21 to 35 days, with an average of 28 days. A cycle begins on the first day of menstrual bleeding and ends the day before the next period starts. Variations in cycle length are common, but a cycle can still be considered regular.
A period is considered late if it has not arrived by the day after it was expected. It becomes significantly late if it is more than five to seven days past the anticipated start date. Tracking one’s menstrual cycle helps identify when a period is truly late.
When to Take a Pregnancy Test
After noticing a late period, the next step often involves taking a pregnancy test. Home pregnancy tests work by detecting human chorionic gonadotropin (hCG), a hormone produced by the body during pregnancy. Levels of hCG begin to rise rapidly once a fertilized egg implants in the uterus, typically about six to ten days after conception.
For the most accurate results, it is recommended to take a home pregnancy test at least on the day your period was expected, or ideally a few days after. While some tests claim to detect pregnancy earlier, testing too soon can lead to a false negative result, as hCG levels may not yet be high enough. Home pregnancy tests are approximately 99% accurate when used correctly, so following the instructions is important.
Common Reasons for a Missed Period Beyond Pregnancy
A late or missed period does not always indicate pregnancy, as several other factors can influence the menstrual cycle. Stress is a frequent cause, as high stress levels can disrupt the hormonal balance that regulates periods. Significant changes in body weight, whether gain or loss, and excessive exercise can also lead to missed periods by affecting hormone production.
Certain medications, including some antidepressants, antipsychotics, thyroid medications, and hormonal birth control, can alter menstrual patterns. Hormonal imbalances, such as those seen in Polycystic Ovary Syndrome (PCOS), commonly result in irregular or absent periods due to disrupted ovulation. Perimenopause, the transitional phase leading to menopause, often causes irregular periods as ovarian hormone production fluctuates. If a period is consistently late or missed and pregnancy has been ruled out, consulting a healthcare professional is recommended to determine the underlying cause.