From the FDA Drug Label
Breakthrough bleeding and spotting are sometimes encountered in patients on oral contraceptives, especially during the first three months of use Breakthrough bleeding, spotting, and amenorrhea are frequent reasons for patients discontinuing oral contraceptives. The cause of spotting prior to ovulation is not explicitly stated in the FDA drug label. Possible causes of spotting may include:
- Hormonal changes: Oral contraceptives can cause changes in hormone levels, leading to breakthrough bleeding and spotting.
- Non-hormonal causes: Non-hormonal causes should be considered and adequate diagnostic measures taken to rule out malignancy or pregnancy in the event of breakthrough bleeding. However, the FDA drug label does not provide a direct answer to the question of what causes spotting prior to ovulation 1 1.
From the Research
Spotting prior to ovulation is most commonly caused by hormonal fluctuations, with a temporary drop in estrogen levels leading to light bleeding as the uterine lining sheds slightly. This phenomenon can be influenced by various factors, including ovulation itself, hormonal imbalances, stress, thyroid disorders, or structural issues such as polyps or fibroids 2. Birth control methods, particularly those involving hormonal contraceptives like drospirenone and ethinyl estradiol, can also lead to breakthrough bleeding due to their effect on the endometrium, as seen in studies where the combination of these hormones results in an atrophic appearance of the endometrium in a significant percentage of subjects 3.
While pre-ovulation spotting is often normal and not concerning, it is crucial to evaluate persistent or heavy spotting, as it may indicate an underlying condition requiring medical attention. Symptoms such as severe pain, unusual discharge, or consistent spotting between periods should prompt a visit to a healthcare provider. Tracking the menstrual cycle and noting when spotting occurs can help identify patterns and determine if the bleeding is related to the normal ovulation cycle or if it signifies an underlying issue.
The use of hormonal therapies, such as those containing estradiol and progesterone, can affect endometrial thickness and potentially lead to spotting, highlighting the importance of monitoring and adjusting treatments as necessary to prevent adverse effects on the endometrium 4. In the context of preventing the recurrence of endometrial polyps, treatments like the levonorgestrel-intrauterine system, drospirenone & ethinylestradiol tablets, and dydrogesterone have shown efficacy, with the levonorgestrel-intrauterine system demonstrating the most significant benefits in terms of recurrence rate, endometrial thickness, and menstrual changes 2.
Given the potential causes and the impact of hormonal treatments on the endometrium, it is essential to approach spotting prior to ovulation with a comprehensive evaluation, considering both the timing within the menstrual cycle and any underlying medical conditions or treatments that may be contributing to the symptom. This approach ensures that any spotting is appropriately managed to prevent morbidity, mortality, and to maintain quality of life.