So, you are saying that you discussed the question of when conception was (not just got a "weeks pregnant" estimate) from your doctor, and he or she said you conceived (using that exact word) on January 7, meaning 11 days after the first guy? Did you give your doctor all the dates of the sex and did you get an ultrasound?
Thanks for the clarifying information you sent to me by p.m.
I am asked by MedHelp to keep the medical questions and answers in the forum and not on p.m.'s so I'll answer you here.
When you said your due date is October 13, I meant it when I asked if January 5 was the last time you had sex with anyone in January. Almost everything you are saying (weeks count and all) suggests you conceived around January 20.
A "weeks pregnant" count used by doctors begins at the first day of the woman's last period. (Not at conception.) If the woman has average 28-day cycles, they begin the count on the real first day of her last period. If her cycles are irregular, they look at the baby and make a measurement, and compute a first day to begin the count that is two weeks earlier than conception. Doctors get so used to this count that they forget it adds two weeks at the front when the woman is not even pregnant yet.
The count of "weeks pregnant" has been done this way for generations because (until ultrasounds) the only signal they had to tell how "far along" a woman was, was to count from when she last had a period. Despite modern technology being able to tell more than this by now, they still use that kind of count. Everything medical is calibrated to it. Doctors, nurses, ultrasound techs, "Your Baby Week by Week", use this count; for them it is so automatic that they don't bother to explain it. If you were told on February 13 that you were 5 weeks 3 days "along," the doctor is saying conceived 3 weeks 3 days ago.
Conception to full-term birth takes 266 days. The pregnancy time period counted by doctors is 280 days from the first day of the [sometimes computed] last period. The estimated due date, if based on your actual baby's measurements as seen by ultrasound, is the more useful date to work from to determine when conception was. If you got the estimated due date from an ultrasound, you can count back from it 266 days on a calendar and that gives you the estimated conception date.
Has your due date changed with further ultrasounds? If not, and if three ultrasounds have told you October 13, you didn't conceive on December 28 or January 5, you conceived a couple of weeks later. If your due date has changed a lot between the first and second ultrasounds, that's a different question.
Yes, a due date of October 13th ties in with ovulation January 20th, theoretical last period Jan 6th. Sperm deposited Jan 15th through Jan 21st would be responsible for the pregnancy. Since you continued the relationship with #2 there is no doubt he is the father.
It seems that your last normal period started before Jan 6th. You first slept with #2 Jan 5th and last slept with #1 Dec 27th. Maybe you had a period between the two guys which you have not mentioned. Perhaps your periods are irregular or you even skipped one. No matter, the due date tells the ovulation date, so #2 it is.
I'm in the exact situation but my period started dec 24 an lasted 5 days I had sex with guy# on the 28/29 and I later had sex with guy #2 on Jan 6th-12 my app says I ovulated jan 6 my cycle is 29 days and my due date by period is sep 30 an my first ultrasound at 6week an 5days gave me the due date of october 4th. I'm wondering who is the dad but everything in me points to guy #2.
Hi, Kimmy, welcome to the forum and thanks for posting in. Your best info is not that from your app (the assumptions on which apps are based come from the average woman's average cycle) and not from the measurement from your last period (because women can ovulate almost any time in their menstrual month), but your first ultrasound is golden. You had the ultrasound on just about the perfect day to be spot-on when figuring the date of conception, and it counts back (from your October 4 due date) to January 11 with a margin for error of only about 1 day. You're right that everything points to guy #2. If I were in your shoes, I'd make plans to test once the baby is born just to put the question to rest forever, but it would just be super surprising if the answer were any different than you already have worked out. Congratulations on your upcoming baby!