QuestionQUESTION: "I am having a dilema...here is my story...i can't remember exactly when was my lmp but i belive was on nov 6th 2009...i had unprotected sex with guy # 1 on nov 26th...i had unprotected sex with guy # 2 on dec 12th and 13th...on the afternoon of dec 13th i took a pharmacy test and it came back positive but since i had a dark line and a faint line i though i wasent pregnant so in the morning of dec 14 th i took a plan b pill during the 72 hours window...later on that day dec 14 th i took another pharmacy test the same thing happend one dark line one faint line,, at this point i was very confused...next day dec 15th morning i went to a clinic and they gave me another test that came back positive for the 3rd time in the past 3 days...on jan 6th 2010 a ultrasound was done stating that i was 8 weeks and 5 days...questions...can a pharmacy pregnancy test show positive 48 hours after unprotected sex?..can an ultarsound be wrong by 15 days or 2 weeks during the first trimester?....they gave a due date of aug 13th 2010 but if my cycles are 34 days not 28 days why the doctor didnt change the date for the 19th of aug?....would of the plan b pill defenetly stop the possible pregnancy?....
I really hope you can help me...
Thanks !!!"
ANSWER: Hi!
Here's how it works: a woman usually ovulates approximately 14 days before her next menstrual period. So if your periods are normally 34 days long, then you would ovulate on day 20 or thereabout.
According to the dates you gave me, that would put your ovulation on around November 26th, give or take a day.
Women can become pregnant if they have unprotected sex within 4-5 days of ovulating. So for you, with a 34 day cycle, that means you're fertile on days 15-25, which, using your dates, would have been November 21- December 1. So between those dates is when you were able to become pregnant that month.
Pregnancy is counted in weeks, starting from the first day of your LMP. So even though pregnancy lasts 40 weeks, you're actually pregnant for 38 of those weeks.
In your case, by the time you were with the second man in December, you were probably pregnant for about 2 1/2 weeks (but in your 5th week because we include the two weeks before) which is why the plan B pill didn't work.
Now for your questions:
A pharmacy test can give an accurate positive reading a day or two before you expect to get your next period, in your case, December 9th. So by December 12 you were already late for you period.
First trimester ultrasounds are accurate, because they're not measuring the size, they're seeing what stage of developement the baby is in. All babies develop certain body parts, limbs, and organs at the same rate. Your baby was showing the developement of a 8 1/2 week old fetus.
You are correct, based on the length of your cycles your baby's due date should be August 19. If you want, you can sit down with your doctor or midwife and explain to them why you want the date changed. Remember, though, that it's called a estimated due date for a reason- no one can predict exactly when your baby will come. It will come when it, and you, are ready.
As for the plan B pill, it would probably have worked had you taken it within 72 hours of November 26.
Please let me known if you want me to explain any of this more deeply, or if you have any other questions.
Good luck,
Sheva
Good luck,
Sheva
---------- FOLLOW-UP ----------
QUESTION: Thanks Sheva you been very helpful, now my last question is..is it posible for a pharmacy pregnancy test to read positive just 48 hours after the actual unprotected sex?....( not getting it confuse with implantation or any of that, just simply after i slept with the guy) ? and how long does implantation occur after fertilization?...( I didn't have any implantation bleeding).I do understand that ultrasound could be off by a few days but will 2 weeks be too much at 8.5 weeks?...If i would of got pregnant on Dec 12th and 13th what would of my lmp period had been for that and just by and around what my ovulation days been in this specific case of dates?.....
Thanks hope I am not asking to much I believe I have my answer and I dont expect you to give me and exactly one I understand this is only base on what information I ma giving you.....
AnswerHi!
It is not possible for a positive pregnancy test to come up only 48 hours after conception. It could come up positive 48 hours after unprotected sex, but that would only be if you were pregnant before that already.
Implantation occurs 7-10 days after fertilization. Fertilization happens in the fallopian tubes, and then the egg has to travel down the tube to the uterus where it implants.
Not everyone has implantation bleeding, and even among the ones that do, the bleeding is usually so miniscule, a few drops the size of a pin head, that she won't even notice it, because it gets diluted by her regular vaginal secretions.
At six weeks the baby looks like a seahorse, sort of, with a head, what looks like a tail, and tiny nubs where the arms and legs will form. The baby is about 1/4 inch long.
At eight weeks the baby is double that size, at a whopping 1/2 inch, has eyes, arms, legs, and tiny fingers, tiny outer ears, lips, a teeny nose, and nipples! It is starting to actually look like a human, although the head is still very large compared to the rest of the baby.
So I don't think an ultrasound would be off by two weeks at this stage.
If you had gotten pregnant in December, your ovulation would have been 14 days before, and your period approximately 20 days before that.
Good luck,
Sheva
