What is the cause of a delayed menstrual cycle by 5 days?

From the Guidelines

A menstrual cycle that is 5 days late on one occasion is usually not a cause for concern. This is a normal variation that can happen due to several factors including stress, changes in weight, travel, illness, or hormonal fluctuations. If you're sexually active, consider taking a pregnancy test to rule out pregnancy, as suggested by various guidelines 1. If your period continues to be delayed beyond a week or two, or if you experience other symptoms like severe pain, unusual bleeding, or if irregular periods become a pattern, consult with a healthcare provider.

Key Considerations

• The menstrual cycle is regulated by a complex interplay of hormones from the brain, ovaries, and uterus, and slight disruptions in this system can cause temporary delays.
• Most women's cycles naturally vary by a few days from month to month, with a normal cycle ranging from 21 to 35 days.
• If you're concerned about your cycle, tracking your periods using a calendar or app can help identify patterns and provide useful information for healthcare providers if needed.

Next Steps

• If an underlying gynecologic problem is suspected, consider an evaluation for interactions with other medications, an STD, pregnancy, or new pathologic uterine conditions, as recommended by 1.
• If an underlying gynecologic problem is not found and the woman wants treatment, NSAIDs for short-term treatment (5–7 days) or hormonal treatment (if medically eligible) with low-dose COCs or estrogen for short-term treatment (10–20 days) can be considered, as suggested by 1.

Important Reminders

• If you experience severe symptoms or if irregular periods become a pattern, consult with a healthcare provider.
• Tracking your periods and being aware of any changes can help in early detection of any potential issues.

From the FDA Drug Label

What is progesterone capsules used for? Treatment of Menstrual Irregularities Progesterone capsules are used for the treatment of secondary amenorrhea (absence of menstrual periods in women who have previously had a menstrual period) due to a decrease in progesterone When you do not produce enough progesterone, menstrual irregularities can occur.

The FDA drug label does not answer the question about a menstrual cycle being 5 days late once.

From the Research

Menstrual Cycle Delay

• A delay in the menstrual cycle can be caused by various factors, including hormonal changes, stress, and pregnancy.
• If the menstrual cycle is only 5 days late, it may not be a cause for concern, as cycles can vary from month to month.

Progesterone Levels and Pregnancy

• Progesterone plays a crucial role in pregnancy, and low levels of progesterone have been associated with an increased risk of miscarriage 2.
• A study found that a single progesterone measurement can predict a non-viable pregnancy with high sensitivity and specificity 3.
• Another study found that progesterone supplementation can reduce the risk of miscarriage and preterm birth in high-risk pregnant women 2.

Progesterone Supplementation and Pregnancy Outcomes

• A study found that progesterone supplementation started on the day of embryo transfer can increase the success rate of frozen embryo transfer cycles 4.
• Another study found that switching from intramuscular to vaginal progesterone after a positive pregnancy test is not associated with an increased risk of miscarriage 5.
• The optimal dose, route, and timing of progesterone supplementation are still unclear and require further research 2, 4, 5.