Contraceptive Pill Effectiveness After One Month of Use

Q: Contraceptive Pill Effectiveness After One Month of Use

Hello, your inquiry has been addressed as follows： Combined oral contraceptives (COCs) must be taken at the same time every day, and correct usage can achieve a 99% effectiveness rate. <br><br>1. <br>Antibiotics (Penicillin, Cephalosporins, Erythromycin, Sulfonamides, Bactrim, Ch

The probability of pregnancy on the first day of sexual intercourse in the second month after taking pre-exposure prophylaxis (PrEP) for one month is generally low, but it is not zero. The effectiveness of PrEP in preventing pregnancy is not its primary purpose, as it is mainly used for HIV prevention. However, if you are referring to emergency contraception or birth control methods, it is important to consult with a healthcare provider

Hello Doctor: I have no prior history of taking oral contraceptives.
I started taking my first pack of Aydin (levonorgestrel and ethinyl estradiol) on December 23, 2019.
I took the pills consistently without missing any doses and completed the first pack.
However, during the course of taking the medication, I frequently experienced side effects such as nausea and gastrointestinal discomfort.
In the last few days of the first pack, my condition improved, and I only had occasional gastrointestinal discomfort, soft stools, or nausea.
Will these side effects affect the contraceptive efficacy? If I experience gastrointestinal discomfort or soft stools, do I need to take an additional pill?
Additionally, after finishing the first pack, my period started on the third day of the 7-day pill-free interval, on January 15.
I began taking the first pill of the second pack on January 20, but that evening I had unprotected intercourse with ejaculation.
Does the 7-day pill-free interval provide complete contraceptive protection? After taking the oral contraceptive for one month, if I had unprotected intercourse after taking the first pill of the second pack, is there a possibility of pregnancy? Or is it necessary to take the pills continuously for 7 days each month before achieving full contraceptive efficacy? Thank you.

S, 20~29 year old female. Ask Date: 2020/01/23

Dr. Zhang Kunmin reply Obstetrics and Gynecology

Hello, your inquiry has been addressed as follows: Combined oral contraceptives (COCs) must be taken at the same time every day, and correct usage can achieve a 99% effectiveness rate.

1.
Antibiotics (Penicillin, Cephalosporins, Erythromycin, Sulfonamides, Bactrim, Chloramphenicol) may reduce the gut flora that aids in absorption, thereby decreasing the effectiveness of contraceptives.
2.
Sedatives (Barbiturates) can increase the metabolism of contraceptives, reducing their effectiveness.
3.
Antiepileptic medications (Primidone, Phenytoin, Carbamazepine) can also increase the metabolism of contraceptives, leading to decreased effectiveness.
4.
Antituberculosis drugs (Rifampicin, Isoniazid).
5.
Antidiabetic medications (Rosiglitazone).
6.
Acetaminophen and Ascorbic acid (Vitamin C) may inhibit the metabolism of estrogen, potentially increasing its concentration in the body and leading to a higher incidence of side effects.
7.
Oral contraceptives can affect the action of anticoagulants.
8.
Smoking can increase the metabolism of contraceptives, reducing their effectiveness.
Based on your described situation, it is recommended to continue taking the medication on schedule.
If side effects are severe, please consult a physician for evaluation.
Thank you! Wishing you safety and health.
Dr.
Zhang

Reply Date: 2020/01/23

More Info

When it comes to understanding the effectiveness of contraceptive pills after one month of use, it’s important to consider several factors, including the timing of the pill intake, any side effects experienced, and the nature of the contraceptive method itself.

Firstly, it’s crucial to note that most combination oral contraceptives, like the one you mentioned (愛逸定), typically require at least seven consecutive days of use to achieve full contraceptive effectiveness if you are starting the pill for the first time. However, since you have been taking the pill consistently and without missing any doses since December 23, 2019, you should be well protected against pregnancy after the first seven days of taking the pill.

Regarding the side effects you experienced, such as nausea and gastrointestinal discomfort, these are relatively common when starting a new contraceptive pill. Generally, these side effects do not affect the effectiveness of the contraceptive pill. The primary concern would be if you experienced severe vomiting or diarrhea, which could potentially reduce the absorption of the pill and, consequently, its effectiveness. If you have not experienced vomiting or severe diarrhea, there is no need to take an additional pill to compensate for these mild side effects.

You mentioned that your period started on January 15, during the seven-day break after finishing the first pack. This is a normal occurrence and indicates that the pill is working as intended. When you began your second pack on January 20 and had unprotected intercourse that same evening, you were still protected against pregnancy. The contraceptive effect of the pill continues as long as you take it consistently, even during the seven-day break.

To clarify, the effectiveness of the contraceptive pill does not reset after the seven-day break. As long as you start your next pack on time, you maintain contraceptive protection. Therefore, having taken one pill from the second pack before engaging in unprotected intercourse means you are still protected.

In summary, based on your consistent use of the contraceptive pill, the mild side effects you experienced should not affect its effectiveness. You are protected against pregnancy during the seven-day break and after starting your second pack. If you have any further concerns or experience any unusual symptoms, it is always a good idea to consult with your healthcare provider for personalized advice.

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