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Had unprotected sex and took Plan B One Step. Having lower back ache and mild cramping. Pregnant?

Mar 2016
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Practicing since : 2011
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I am a 44 (almost 45) year old woman. I have always been very fertile. My periods have always been normal until August 2013 when I was supposed to get my period on August 19 and I did not get it until August 24. Then in September, I should have gotten my period on September 21, but instead I got it on September 17 and it lasted for almost 6 days. On September 30 @ about 11:30pm I had unprotected sex and again the next morning, October 1st around 6am. I took Plan B One Step pill at 6:30pm on the evening of October 1st (so approximately 18 hours after the first time and 12 hours after the time in the morning. I had no side effects from the pill. It is now October 9th (8 days later) and I still have had no bleeding at all. My period is not due until Monday October 14th. I am concerned because a couple of days ago (October 7th) I started having a slight lower back ache and mild cramping (mostly on the lower right side but sometimes all over). I am worried that these could be signs of pregnancy. I have been reading about Plan B and I am worried it wasn't effective because I took it when I was ovulating. I have taken 3 First Response Early home pregnancy tests (2 yesterday and 1 today) which say they can detect pregnancy within 6 days before a missed period. Yesterday would have been 6 days and today is 5 days before my period should start. They are all negative, but is that possible to know so soon? I am having a nervous breakdown over the possiblilty of being pregnant and I cannot wait to see if I miss my period!!!! Please tell me your thoughts given all of the factors (dates, symptoms, etc...). Do you think I am pregnant? Are the symptoms normal for my situation? Thank you.
Posted Tue, 29 Oct 2013 in Menstruation and Miscarriage
Answered by Dr. S Patra 1 hour later
Brief Answer:

Detailed Answer:

Thanks for writing to us.

First of all, you did unprotected sex close to your fertile days or ovulation day. However, you took Plan B One step within first 24 hrs of sex which give you more than 95% protection against unwanted pregnancy.

Second thing, most women get a withdrawal bleeding within 7-10 days following taking the pill. However, it is not an essential criteria for effectiveness of the pill. You can wait few more days.

Thirdly, it is too early for pregnancy test and you do not get accurate result due to low beta-hCG in body. Ideal time of pregnancy test is 2 weeks after unprotected sex or around due date/ missed period. At that time, pregnancy test gives more than 95% positive result. 96-99% positive result is achieved 7 days after missed due date.

Lastly, you are now presenting with abdominal cramp and backache which are mostly associated with Premenstrual Symptoms which indicate you will get your period shortly. Therefore, it is better to wait till your due date and if you miss it, you need to repeat the home pregnancy test. Here, possibility of being pregnant is quite low in my point of view.

Hope, I have answered your query. If you need any clarification, you can freely ask me.

Wish your good health and take care yourself. Don't be worried.

Dr Soumen

For future query, you can directly approach me through
Above answer was peer-reviewed by
Follow-up: Had unprotected sex and took Plan B One Step. Having lower back ache and mild cramping. Pregnant? 21 minutes later
So, even though it was on my ovulation day & he did ejaculate inside me (sorry for the details) the Plan B is still 95% effective?

And the fact that I have had no bleeding yet is not a bad sign?

Last thing... is it normal that I seem to be having the cramping mostly on the lower right side? What might that indicate to you?

The Fast Response Early test says that it can detect up to 6 days before period, today is only 5 days before and I took 2 (both negative) but you think that is not real?
Answered by Dr. S Patra 1 hour later
Brief Answer:

Detailed Answer:

Thanks for follow up query. Followings are my comments:

1) Yes, Plan B gives more than 95% protection against unwanted pregnancy in spite of unprotected sex on ovulation day or fertile period as you took the tab within first 24 hrs.

2) Withdrawal bleeding is a common feature after taking the pill. But, it is not a mandatory criteria for pill effectiveness. So, don't be worried.

3) Abdominal cramp and backache are most common prior to commencement of period. However, they are also seen in early pregnancy and vary women to women.

As per presentation, they are more indicating with period signs. You must wait few more days or till period due date before repeating the pregnancy test.

4) Fast Response Early Test can detect possible pregnancy before period due date. But, it does not give always 100% accurate result due to low level of beta-hCG in body.

Therefore, it is better to undergo home pregnancy test after missed period. One blood test for beta-hCG is required after one week for confirmation.

Hope, I have guided you properly. If you don't have any query, you can close the discussion.

All the best. Good luck.

Dr Soumen
Above answer was peer-reviewed by
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