Hi I'm new to this and very confused. I was wondering how soon after intercourse does the gestational sac first begin to form?

The egg (follicle) is working it's way down the fallopian tube when many sperm run into it and try to break through it. If one succeeds, the outer layer of the egg instantly changes to an impermeable state and no other sperm can get through. The sperm have a maximum life of about 3 days inside the woman's body, although fertilization (conception) generally happens sooner than that (fresh sperm actually can't impregnate until they have undergone some changes over several hours). The fertilized egg starts growing within 24 to 36 hours and continues on down to the uterus (hopefully - if not, an ectopic pregnancy occurs) where it attaches to the uterine wall. That's when the gestational sac forms. This is all just a matter of a few days to a week. Each step has variations, so there is no exact time schedule.

The sac won't be seen on ultrasound that early, however, so if you are wondering when you conceived, this is not the information you need. Answer below if you want to know that.

Ok thank you so much for your reply. Here's why I ask. I am 29weeks pregnant and confused by who. My boyfriend and I live together, on March 25th 2013 I had some spotting for about 3hrs(then nothing). Me and my boyfriend have sex everyday including that day and every day after that ( 25,26,27,28,29,30,31,April 1,2,3,4) late evening on the 4th we got into a huge argument due to messages in his phone so he called his self so-called moving out... So that night, fed up with crying I called my ex (mistake) he came over around 12midnight (basically April 5th) we then had sex around 5am. He left and later that day around 2pm my boyfriend came back home.. too scared to tell him, I kept quiet and said nothing of it. On April 26th I found out I was pregnant the er said they only see a sac so I'm about 4-5weeks. But did I mention on April 4th I had a doctors appointment because I was complaining about not feeling well and my breast hurting badly (scared it was cancer or something) she asked would I like to take a pregnancy test I said sure OK, she took it and said it came back negative. But the er said on the 26th I was about 4-5weeks... So why question is was pregnancy already beginning around March 25th that's where the spotting came from,if so does that mean it was just to early to pick up at my docs appointment?

Sex with boyfriend many days through April 4.
Pregnancy test on April 4 negative.
Sex with ex April 5, only.
On April 26, doctor said 4 - 5 weeks pregnant.
Tell the doctor why you want to discuss the size of the sac on the ultrasound.
It might be big enough to put you safely into March, but the doctor may tell you that there is a possibility that it was less than 4 weeks. It is possible for a 21 day old embryo to show on ultrasound.
Spotting on March 25 can be just a very light period, or it can be spotting after first getting pregnant.
5 weeks before April 26 = March 22, and 4 weeks = March 29. But again, doctors just estimate, so say why you want to try to be more exact.
There is no way you will know 100% until the baby is born and you have a DNA test.

Ok I have a appointment in the a.m,and I'm going to ask her for a copy of my records as well as the ones from the er. Because I've gotten advice from other doctors who have said things like"if I told her at my appointment on april 4th that I spotted for only 3hrs with right abdomenal pains and cramps as well as tenderness in breast on the 25th of march"she should have known to do a blood test as well and not just a urine test especial since the appointment was at 3pm and not in the a.m! So after hearing all that I've already felt like I have a doctor who doesn't know exactly what she's doing or just feels like she knows what's best and doesn't care to hear my out, not only that, I'm not one of the people who's body go through different changes during each month, I barely get sick or have prblems with my body so 9 times out of 10 when I'm feeling a certain way as far as my body I'm right. I mean I already have a 6yr old,so the sign were more noticeable to me,like my body was giving me red flags that something was wrong... her pee test says "negative" then all of a sudden 2wks later I turn out pregnant... I fell so strongly that I was right all along because why after 6 whole yrs out of nowhere I start getting these same symptoms.. I think I may switch doctors...

There's no way to determine who the father is any way but a DNA test. Doctors judge based on a best guess, not an exact one, and their best guess can be off 2 weeks either way, for a total of 4 weeks.

They can't base it on your last period, ultrasound, or any other means. The only way to know for sure who the father is without a DNA test, is by only having sex with one person. That's not a judgement, that's just a fact.

You'll need to get a DNA test once the baby is born. That's the ONLY way to determine who the father is. No doctor can tell you right now.

I'm very well aware of the facts about sex,that was not my question. I asked about the gestational sac. which your comment said nothing about. I did not ask about DNA's at all! Ima need for everyone replying to me to least try and answer the question at hand somewhr in your comment. Because any other comments and opinions (especially if it sounds negative or somewhat sarcastic) is very much irrelevant!

The gestational sac does not develop until the egg has been fertilized and has implanted into your uterus.

I should have quoted your post, and the title of your thread before it was merged with this thread. Sadly, I didn't. I remember your thread, and as I recall, you had sex with two different men around the time you ovulated. If I'm wrong, then I apologize, but I wouldn't have mentioned a DNA test unless you had mentioned two different possible fathers.

Since you obviously don't want that advice, I'll bow out. Good luck to you. I hope you find the answers you're looking for.

The gestational sac does not develop until the egg has been fertilized and has implanted into your uterus.
Thank u for your response. So that means since the hospital said they found a sac at 4-5weeks that takes me back to march 25 and/or possibly a little further. Right?

I should have quoted your post, and the title of your thread before it was merged with this thread. Sadly, I didn't. I remember your thread, and as I recall, you had sex with two different men around the time you ovulated. If I'm wrong, then I apologize, but I wouldn't have mentioned a DNA test unless you had mentioned two different possible fathers.

Since you obviously don't want that advice, I'll bow out. Good luck to you. I hope you find the answers you're looking for.
Ok if you meant no harm I do apologize as you can imagen the subjuct is already frustrating to me. Also as far as ovulation I'm very irregular with periods which means I could have ovulated at any time I'm not on a 28 day cycle,I actually hadn't had a menstrual period in 6+ yrs since before I had my daughter,because after her I try the IUD which completely messed up my body. That's why when I saw the spotting on march 25th.. curiosities began to rise.

That means that you will have to have a DNA test done after the baby is born to determine paternity. Gestational dating is an in exact science based on certain formulas. It can be incorrect + or - up to 2 weeks either way.

I know this probably isn't the news you wanted to hear, but those are the facts.

I covered this in my first response. Maybe I went into too much detail and it was lost.
I also explained that a report of 4-5 weeks was an estimate.
Unless the ultrasound shows a sac that is significantly bigger than the what might be seen when it is first visible, then you have NO way of knowing whether you conceived earlier than April 5th! And you can't blame the doctor who just did a urine test unless you told her about 2 partners and your concerns.
I'm going to go out on a limb and say that I think the odds are better than 50/50 that you conceived before April 5.

I covered this in my first response. Maybe I went into too much detail and it was lost.
I also explained that a report of 4-5 weeks was an estimate.
Unless the ultrasound shows a sac that is significantly bigger than the what might be seen when it is first visible, then you have NO way of knowing whether you conceived earlier than April 5th! And you can't blame the doctor who just did a urine test unless you told her about 2 partners and your concerns.
I'm going to go out on a limb and say that I think the odds are better than 50/50 that you conceived before April 5.
Ok thank you again. And the reason for me being upset with the doctor is because by the time I went in on April 4th complaining of all these worries,pains and symptoms for quite a while,my ex hadn't occurred yet until the next day. So after finding out all about hcg levels and how soon they may or may not be detected depending on which test you take urine/blood work, I feel she should have as a doctor ruled out all so-called possibilities. Then the 5th definitely would not have occurred.. I feel stongly that I was already pregnant before the 5th due to just knowing my body. I also remember telling on April 1st " ok baby we gone have to make a doctors appointment something its right,I think I'm pregnant" filled with excitement,he replied " bae you bet not be april fooling me" I explained I was serious as a heart attack. So we made the appointment for the 4th,and both attended. That same day, I was due to began my depo because shot,but after the urine test she asked when was our last unprotected sex and we explained that it was about 2hrs prior to the vist, so she said she couldn't give me the shot due to possible pregnancy, since it had not been 2weeks of "no sex or "protected sex with condom". Well guess ill just have to go with my gut and walk by faith.

I covered this in my first response. Maybe I went into too much detail and it was lost.
I also explained that a report of 4-5 weeks was an estimate.
Unless the ultrasound shows a sac that is significantly bigger than the what might be seen when it is first visible, then you have NO way of knowing whether you conceived earlier than April 5th! And you can't blame the doctor who just did a urine test unless you told her about 2 partners and your concerns.
I'm going to go out on a limb and say that I think the odds are better than 50/50 that you conceived before April 5.
So what I'm saying is by the time April 4th came around there was no need to tell her of 2 partners,my ex didn't exist in any way.

Ok if you meant no harm I do apologize as you can imagen the subjuct is already frustrating to me.

First, no one here means harm. But this site is different from others. We try to provide solutions, not just answers to questions. In post #3 you said; "Here's why I ask..." and proceeded to explain about sex with your ex. That's what Alty was responding to and your response to her was out of line.

That calculating conception is an inexact science and there is a possibility you conceived with your ex. And the ONLY way to be sure is with a DNA test after birth.

What you are saying about the treatment you received does justify a lack of confidence in your doctor and a switch. But it doesn't change the fact that you can't be sure who the father was until you test.

I'm very well aware of the facts about sex,that was not my question. I asked about the gestational sac. which your comment said nothing about. I did not ask about DNA's at all! Ima need for everyone replying to me to least try and answer the question at hand somewhr in your comment. Because any other comments and opinions (especially if it sounds negative or somewhat sarcastic) is very much irrelevant!
Shanny, we are all volunteers here with other full time jobs. Everyone tries to help in their own way. 'Any other comments and opinions' should not bother you if you are coming here for free advice. No one is trying to be negative or sarcastic.
Please be respectful on this site.

Well guess ill just have to go with my gut and walk by faith.

You can do that if you want and worry the rest of your life. Don't you think that it is in the best interest of the baby to know what health problems may arise due to genetic issues? Your child, and the father, deserve to know the truth.

You can continue to live in the land of denial, or you can do the best thing by your child and find out who is genetically the father of your child. There are many genetic disorders that may not present at birth, but may present at a later age. At that time your child, or your partner, will find out that you have lied and cheated.

Unless you have the DNA test, you will live the rest of your life a lie. If it comes out later that your partner is not the father of your child you risk losing the trust of not only your partner, but your child as well.

"Oh, what a tangled web we weave when we practice to deceive."

As J_9 points out, the likelihood of it being determined later on is very high. Medical procedures and tests will likely bring it to light.

I'm not sure for what reason this spacific (question) turned into a discussion focused only on dna which I clearly don't remember saying I wasn't getting, I was only curious about the sac development.. but ima gone head and delete this myself from this website... cause my attitude too bad for this...

You were given DNA information because there is clearly a question of paternity. You had sex with two men which means either one could be the father.

Oh, you cannot delete this from the website. It is now permanent. Had you read the TOS of the site when you signed up you would have known that.

You were given DNA information because there is clearly a question of paternity. You had sex with two men which means either one could be the father.

Oh, you cannot delete this from the website. It is now permanent. Had you read the TOS of the site when you signed up you would have known that.
Ok but paternity was never my question, somehow everybody is overlooking the question and going str8 to replying to a comment I made.and No what I said was I'm deleting myself from this website.. not this comment cause at this point I don't give a... And I'm done going back and forward on a damn website ! Not my thing, I'm a in person type female... now good day

Ok but paternity was never my question, somehow everybody is overlooking the question and going str8 to replying to a comment I made.and No what I said was I'm deleting myself from this website.. not this comment cause at this point I don't give a... And I'm done going back and forward on a damn website ! Not my thing, I'm a in person type female... now good day
Your question was answered by the first person who responded.

You cannot delete yourself. Stop posting so your name will slowly float to the bottom of the barrel.

Ok thank you so much for your reply. Here's why I ask. I am 29weeks pregnant and confused by who. My boyfriend and I live together, on March 25th 2013 I had some spotting for about 3hrs(then nothing). Me and my boyfriend have sex everyday including that day and every day after that ( 25,26,27,28,29,30,31,April 1,2,3,4) late evening on the 4th we got into a huge argument due to messages in his phone so he called his self so-called moving out... So that night, fed up with crying I called my ex (mistake) he came over around 12midnight (basically April 5th) we then had sex around 5am. He left and later that day around 2pm my boyfriend came back home.. too scared to tell him, I kept quiet and said nothing of it. On April 26th I found out I was pregnant the er said they only see a sac so I'm about 4-5weeks. But did I mention on April 4th I had a doctors appointment because I was complaining about not feeling well and my breast hurting badly (scared it was cancer or something) she asked would I like to take a pregnancy test I said sure OK, she took it and said it came back negative. But the er said on the 26th I was about 4-5weeks... So why question is was pregnancy already beginning around March 25th that's where the spotting came from,if so does that mean it was just to early to pick up at my docs appointment?

This is from post #3 in this thread. I've bolded the pertinent parts. This clearly indicates that your reason was asking was concern over who the father is.

The question about sac was answered right off the bat, and again in other responses. That's why subsequent responses dealt with the heart of the issue.

We don't delete threads or accounts here. If you feel you don't want to use this site further, then just stop logging in.

This is from post #3 in this thread. I've bolded the pertinent parts. This clearly indicates that your reason was asking was concern over who the father is.

The question about sac was answered right off the bat, and again in other responses. That's why subsequent responses dealt with the heart of the issue.

We don't delete threads or accounts here. If you feel you don't want to use this site further, then just stop logging in.

Thank you Scott. I answered the way I did because it was very obvious that the OP was asking about when the sac forms, etc, to determine when she became pregnant. Since there were two partners, why ask this question unless you're trying to determine who the father is? This entire thread is very much about wondering who the father is, which is why I said she'd need a DNA test.

It's obvious that the OP is upset because we did answer the question, and couldn't tell her who the daddy is. We see that all the time here. People don't want to accept that we can't tell them who the father of their child is, that only a DNA test will be able to tell them, no matter how many ultrasounds, etc. the person has.

To the OP, I'm sorry that we couldn't tell you what you really wanted to know. I do hope you get the DNA test once the baby is born, and I really do wish you all the best, even after the way you acted on this thread.

Good luck.