Emergency Contraceptive Pills: Common Questions and Concerns

Questions related to emergency contraceptive pills?

Due to my menstrual cycle being consistently light for several months, my doctor performed a transvaginal ultrasound during my last period and determined that it was an anovulatory cycle.
The doctor prescribed Diane (21 pills) to help regulate my cycle.
I have a few questions regarding this contraceptive pill.

After taking the pills for 21 days, I will stop for 7 days, during which my period is expected to occur.
Typically, isn't the menstrual period supposed to come about 14 days after ovulation? Does this mean that ovulation occurs during the last week of taking the pills? If that is the case, wouldn't the chances of pregnancy be quite high during that week? Why is it commonly stated that the likelihood of conception is higher during the last 7 days?
Additionally, if I want to use LH test strips to detect ovulation, will taking the contraceptive pill affect the interpretation of the results? Also, will taking the contraceptive pill have any impact on my basal body temperature? Thank you, doctor.

Niming, 20~29 year old female. Ask Date: 2017/03/23

Dr. Huang Jianzhong reply Obstetrics and Gynecology

Due to my menstrual period being consistently light for several cycles, my doctor performed a transvaginal ultrasound during my last period and determined that it was an anovulatory cycle.
The doctor prescribed Diane (21 pills) to help regulate my cycle and mentioned that it is a form of oral contraceptive.
I have several questions regarding this:
After taking the pills for 21 days and then stopping for 7 days, will my period occur during that 7-day break? Isn't it true that menstruation typically occurs about 14 days after ovulation? Does this mean that ovulation would happen in the last week of taking the pills? If that is the case, wouldn't the chances of pregnancy be quite high during that week? Why is it said that the chances of conception are higher during the last 7 days?
Additionally, if I want to use LH test strips to detect ovulation, will taking oral contraceptives affect the interpretation of the results? Also, will taking oral contraceptives have any impact on my basal body temperature? Thank you, doctor.

Answer: Taking oral contraceptives for 21 days followed by a 7-day break typically leads to a withdrawal bleed, which is not the same as a true menstrual period.
The timing of ovulation can be altered by the contraceptive pills, and ovulation does not occur during the pill-taking phase.
Therefore, the likelihood of pregnancy during the last week of taking the pills is low.
The perception that the chances of conception are higher during the placebo week is often due to misunderstanding; the actual ovulation and conception chances are influenced by the hormonal regulation provided by the pills.

Using LH test strips while on oral contraceptives may not provide accurate results, as the hormones in the pills can suppress ovulation and affect the interpretation.
Additionally, taking oral contraceptives can stabilize basal body temperature, making it less reliable for tracking ovulation.

Reply Date: 2017/03/23

More Info

Emergency contraceptive pills (ECPs) are a crucial topic in reproductive health, especially for those who may find themselves in situations where unprotected intercourse has occurred or contraceptive failure has taken place. Understanding how these pills work, their effectiveness, and their implications is essential for informed decision-making.

Firstly, ECPs primarily function by preventing ovulation. If taken before ovulation, they can inhibit or delay the release of an egg from the ovary. If ovulation has already occurred, ECPs are less effective. This is why timing is critical; the sooner they are taken after unprotected intercourse, the better the chances of preventing pregnancy. ECPs are most effective when taken within 72 hours of unprotected sex, but some types can be effective up to 5 days after.

Regarding your specific questions about Diane (a combined oral contraceptive pill), it is important to clarify how these pills work. When you take Diane, it contains hormones that regulate your menstrual cycle. The 21 days of active pills are designed to prevent ovulation, and during the 7 days of placebo pills, you will typically experience withdrawal bleeding, which mimics a menstrual period. This bleeding occurs not because you have ovulated, but due to the sudden drop in hormone levels when you stop taking the active pills.

To address your concern about ovulation during the last week of taking the pill, it’s important to note that the hormones in Diane are meant to suppress ovulation throughout the cycle. Therefore, if taken correctly, you should not ovulate during the entire cycle, including the last week. The idea that the risk of pregnancy is higher during the placebo week is a common misconception. The risk of pregnancy is primarily associated with missed pills or incorrect usage of the contraceptive method.

If you are using LH (luteinizing hormone) test strips to detect ovulation while on Diane, the results may indeed be affected. The hormones in the pill can suppress the natural hormonal fluctuations that trigger ovulation, potentially leading to false negatives on ovulation tests. Therefore, if you are on hormonal contraceptives, relying on LH tests to determine ovulation is not recommended, as they may not provide accurate information about your fertility status.

As for basal body temperature (BBT), hormonal contraceptives like Diane can also influence your BBT readings. Typically, a rise in BBT indicates that ovulation has occurred, but since Diane prevents ovulation, your temperature may not show the typical pattern seen in natural cycles. This can make it challenging to use BBT as a reliable method of tracking ovulation while on the pill.

In summary, ECPs and hormonal contraceptives like Diane are effective methods for preventing pregnancy when used correctly. Understanding how they work, including their effects on ovulation and menstrual cycles, is crucial for making informed choices about reproductive health. If you have ongoing concerns or specific questions about your menstrual cycle or contraceptive methods, it is always best to consult with your healthcare provider for personalized advice and guidance.

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