[Lreffner]

Hello. My doc says I'm 7 weeks 5 days pregnant on feb. 22 2017. Idk when I conceived. My lmp was dec. 19th 2016. I had sex on vacation between dec 25-29 and then when I got back between dec 30-4th 2016. My due date is oct 6 2017. When is it most likely that I conceived?

[Curlyben]

When you had sex..
If there is a doubt concerning paternity the only way to be sure is a DNA test after the birth.
The dates are far too close to make even a consider guess.

[ScottGem]

Calculating conception dates is an inexact science. Either of those date ranges could have resulted in conception. This should only be an issue if you had multiple partners during those periods.

If you did, then you should inform each of your partners that they may be the father. The only way to know for sure will be a DNA test after the child is born.

[Alty]

Ultrasound or due date based on LMP, are a best guess, not an exact science. They can be off two weeks either way, (two weeks earlier, or two weeks later) and anything in between. In other words, with dates this close there's no way to even give an educated guess as to when you conceived. The 7 weeks 5 days guess is just a guess. My due date changed many times during my pregnancy based on the most current ultrasound, or how I was measuring, or milestones hit, and I knew exactly when I conceived.

As has already been said, if this is a question of paternity, there's no way to know who fathered the baby based on these dates. It's just too close together. You'll have to wait until baby is born and get a DNA test.

If it's not a matter of paternity, don't stress, just relax and enjoy the pregnancy, and make sure to take good care of yourself. Eat well, take your prenatal vitamins, never miss a doctors appointment.

I wish we could help, but even your doctor wouldn't be able to tell you which date you conceived.

Good luck.

[Fr_Chuck]

If these are different men, there is no way to tell without a DNA test. There is no way to know when it is so close together, the best testing is give or take a week or two.

[Lreffner]

What if the first encounter wasn't as successful of an ejaculation (pull out) as the second encounter?

[J_9]

The withdrawal method (pull out) is not reliable as there is still sperm in the early fluids. With encounter dates this close together, the only foolproof method of identifying paternity is a paternity test after the baby is born.

[Cat1864]

While there isn't supposed to be sperm in pre-ejaculate (male lubrication), the valve that holds the semen back can leak allowing viable sperm into the pre-ejaculate. Plus, depending on when he last ejaculated, there could be left over sperm in the tubes.

A brief, very simplified, lesson in conception: Under certain conditions sperm can remain viable in the female body for approximately a week. It takes a day to three days for sperm to reach the Fallopian Tubes. The sperm waits for an egg to be released. If an egg is released and fertilized, it takes another couple of days for it to travel down to the uterus and implant. Implantation is when the pregnancy begins.

Now, because sperm can survive for so long in the female body and because your dates for sex are so close together, no one can tell you for certain when you conceived. Even the earliest ultrasound which is the most accurate can be off by a week.

[ScottGem]

Sorry, but there is no way to be sure. You need to inform all partners.