Pregnancy Chances After Antibiotics and Emergency Contraception

What is the likelihood of getting pregnant?

At the end of July, I underwent surgery and took antibiotics, which caused my menstrual cycle to change to 38 days.
My menstrual bleeding in August lasted for 7 days (from August 28 to September 3).
I took antibiotics on September 8 and finished them on September 15, after which I did not use them again.
I know that antibiotics can affect menstruation to some extent.
My period in September is currently delayed by 5 days.
I took a home pregnancy test and it was negative.
I had sexual intercourse on September 3 and September 14, both times using a condom.
On October 1, I had sexual intercourse again under the same conditions, using a condom, but during the check, I found a small hole in the condom, not in the reservoir tip, but at the base of the penis, which caused a small spray like being pricked by a needle.
Because I was worried, I immediately took an emergency contraceptive pill (ella 30mg) and a bottle of a sweet and sour liquid that the pharmacist said was for replenishing the body.

1.
What is the likelihood of pregnancy in this situation?
2.
Is the delay in my September period due to the antibiotics and the emergency contraceptive pill? How much longer should I wait?
3.
Could taking antibiotics for a week in the middle of the month affect the effectiveness of the emergency contraceptive pill?

layla, 10~19 year old female. Ask Date: 2020/10/03

Dr. Cao Guotao reply Obstetrics and Gynecology

Hello, the chances of pregnancy should be low.
Just observe for now.
Wishing you good health.

Reply Date: 2020/10/03

More Info

When considering the effects of antibiotics and emergency contraception on pregnancy chances, it's essential to understand how these medications interact with your body and menstrual cycle. Based on your situation, let's break down your concerns and provide clarity.

1. Chances of Pregnancy: Given that you had sexual intercourse on September 3 and September 14, and used a condom during both instances, your risk of pregnancy is relatively low. The condom's integrity is crucial; however, you mentioned a small hole near the base of the penis, which could potentially lead to sperm leakage. Since you took emergency contraception (ella) shortly after the incident, this further reduces your chances of pregnancy. Ella is effective up to 120 hours after unprotected intercourse and works primarily by delaying ovulation. If you have taken it within the recommended timeframe, it should significantly lower the risk of pregnancy.

2. Delayed Menstruation: Your menstrual cycle has been affected by various factors, including the antibiotics you took and the emergency contraception. Antibiotics can sometimes alter the menstrual cycle, but they typically do not cause significant delays. The emergency contraceptive pill can also lead to changes in your cycle, including delayed menstruation. It is not uncommon for periods to be irregular or delayed after taking emergency contraception. Since your period is currently five days late, it could be a result of the emergency contraceptive, the antibiotics, or simply a natural variation in your cycle. It is advisable to wait a few more days and consider taking another pregnancy test if your period does not arrive.

3. Impact of Antibiotics on Emergency Contraceptive Effectiveness: Most antibiotics do not significantly affect the efficacy of emergency contraceptive pills like ella. However, there are some exceptions, particularly with certain antibiotics that can induce liver enzymes, which may affect hormone metabolism. The antibiotics you mentioned are generally not known to interfere with the effectiveness of emergency contraception. Therefore, it is unlikely that the week of antibiotic use impacted the effectiveness of the emergency contraceptive you took.

In summary, while there is a slight possibility of pregnancy due to the small hole in the condom, the use of emergency contraception should have effectively minimized that risk. The delay in your menstrual cycle is likely due to the combination of factors, including the antibiotics and the emergency contraceptive. If your period does not arrive soon, consider consulting with a healthcare provider for further evaluation and guidance. They can provide personalized advice and may suggest a blood test for pregnancy if necessary. Always remember that maintaining open communication with your healthcare provider about any medications and their potential effects on your reproductive health is crucial.

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