Pregnancy test vs. ultrasound

ipip12

This is potentially my first child and I have been to the ultrasounds :) I am a male.

Had sex with a woman on October 9th latse at night. She then showed me a positive pregnancy test on October 14th at noon, First Response. It was not a "squinty" - the line wasn't dark pink, but it was definitely there and somewhat colourful. No doubt whatsoever as to whether or not it was positive.

At our November 15th ultrasound they gave a GA of 7 weeks 2 days. From my understanding the average date of conception would be... October 9th. Subsequent ultrasounds have not strayed from this assessment, but from my understanding the margin of error grows as things progress.

Tests on the subsequent days were much darker and I'd say they became a solid pink line about 2 days after the initial test on the 14th.

However, people in my life have told me that it is highly improbable, or downright impossible, to get a clear positive test that early. I don't have information regarding LMP but they suggest she was already pregnant.

I won't go into the drama, but I've learned there was someone else at the end of September. Yes, I'll be asking for a paternity test. Just a couple of questions based on your personal experiences or knowledge:

- Has anyone had babies that consistently measure a week or so "smaller" than one would otherwise expect, based on a known date of conception?

- Has anyone here had a relatively decisive positive test at 5 DPO?

izza2

At 5dpo the blastocyst is still moving from the fallopian tube to the uterus. It hasn’t implanted yet. At most, it’s near the uterus and ready to implant. But her HCG levels would not be detectable for testing, let alone clear test lines.

She may have ovulated prior to intercourse by up to 2 days, meaning she was actually 7 DPO when she tested. She could have had a faint positive at that point. That’s the only likely scenario where your interaction with her resulted in your sperm fertilizing the egg.

That being said, if her previous partner was 1.5-2 weeks prior to you, it’s much less likely that they’re the father.

There are options for paternity testing while in utero, and I would suggest looking into these to give you both peace of mind one way or another.

ipip12

I've asked for prenatal test and she refused. Thanks for your reply; just wondering if you had any thoughts regarding the accuracy of ultrasound readings?

00kim00

I did IVF, so we have an exact known date. My early ultrasounds measured 5 days later/"smaller", so it's definitely possible to be off. I can't speak to personal experience with the testing, but it does seem unlikely. I agree that a paternity test seems prudent.

meggyme

With all you’ve said I probably wouldn’t be sure until you have a paternity test regardless of what anyone here says. That said, getting a bright positive positive 5 days after sex is unusual.

izza2

@ipip12 The babe could definitely measure bigger or smaller in utero. Ultrasounds are great but they’re not always exact. Take the measurements with a little grain of salt.

I’d be curious why she’s refusing paternity testing…
Good luck either way!

emeraldcity603

Getting a dark line 5 days after intercourse is impossible. The most you would have seen is a super super faint line that would have been a squinter. The late September partner is most likely the father. She can refuse the paternity test all day long but a court order can force her hand once the baby is born. 

swizzlemalarkey

It sounds like she wants you to be the father, whether or not you are. Why would she have tested 5 days after? It’s rare to get symptoms that early as well. Untradounds aren’t always perfect. So I would definitely be demanding a paternity test. She could be lying and there could’ve been someone even a few days before you as well…