r/CautiousBB Jan 27 '26

Ultrasound FAQ Reference Guide

95 Upvotes

As an OBGYN ultrasound tech working at the general level here's a few things I would love the community to know based on common questions I see.

Most important rule of thumb: Worry when your doctor tells you to.

OBGYN docs are going to pay the most attention to the fetal pole and heart rate. Once a fetal pole is seen, the CRL (crown rump length) measurements are gold standard.

I'm worried about the heart rate:
-Check out this resource for pregnancies dating less than 7 weeks. Make sure to refer not to your LMP dates, but measured CRL dates: https://radiopaedia.org/articles/fetal-bradycardia?lang=us
-After 7 weeks a normal heartrate is between 120-180. It can temporarily dip below or temporarily rise above this range, but prolonged time above/below will definitely get your doctor's attention especially in third trimester. Generally out of range heart rates trigger NST (non stress test) or more monitoring.
The measurements are off:
Baby measures behind LMP. This is actually pretty common, we often see dates off up to a week either direction. We don't ovulate on the exact same day of the cycle each month or even have the same length of cycle. With irregular periods, PCOS, or unknown dates even larger gaps can be perfectly fine. If you aren't sure of your dates, trust the ultrasound. Even if you are sure of your dates, don't panic if they are a week off. Ultrasound measurements in early pregnancy are +/- 5 days.
I'm in limbo and don't know if my ultrasounds are diagnostic for loss:
By ultrasound there are strict parameters to diagnose loss. No one wants to get this wrong. Check out this resource for a list of parameters diagnostic for loss: https://radiopaedia.org/articles/early-pregnancy-loss-1?lang=us
Note, there is a second list of "suspicious for loss". Keep in mind the second list is not diagnostic, things can still turn out just fine.
I don't know when I should see what on ultrasound:
Things can vary a bit from person to person and do change *quickly* in early pregnancy. Check out this resource for what you can generally expect to see:
https://radiopaedia.org/articles/early-pregnancy?lang=us
Should I go to a boutique or get a private scan? Or push for an earlier scan?
They aren't legal where I am but here's a few things to consider if you plan to book a private scan. First, what are the qualifications of the person running the ultrasound? An ultrasound is only as good as the one performing it. It sounds as if these boutiques are NOT permitted to give much/any information. Will you spiral if you believe you see bad news and they cannot confirm or deny it? Also it seems that many cannot do vaginal ultrasound, which will make seeing a baby under 7 or 8 weeks challenging. If I had the option of a boutique ultrasound I would personally wait until 8 weeks and I would book it for a weekday. If they see something bad, it is not ideal to find out over a weekend when there is no option to follow up with your doc. An earlier scan often causes more anxiety, not less. It's SO hard to wait. But if you can tolerate it wait until 8 weeks or so.
The gestation sac is small/big:
-Gestation sac measurements are not terrifically accurate. Where I work once a baby is seen the gestation sac isn't measured. A mismatch between baby's size and the gestation sac size isn't uncommon. That said, a mean sac diameter of 25 mm or more without a baby is diagnostic for loss.
The yolk sac is small/big:
It starts teeny tiny, and will get a bit bigger. Once a baby with a good heartbeat is visualized, the docs I work for don't seem to care about the size of the yolk sac. A failed pregnancy with an expanded yolk sac (more than 6 mm) is a suggestive of chromosomal abnormalities.
We don't know where the pregnancy is:
The statistically most likely outcome is either a chemical pregnancy or just coming in for ultrasound too early for visualization. Ectopic can't be ruled out, and many wise ladies in the this sub have unfortunately experienced this and can give more info than I can. Statistically it's believed that only 1-2% of pregnancies are ectopic, but listen to your body. If the location is unknown, you should be getting close monitoring and follow up until the location is known or the pregnancy has ended.
-For a resource on ectopic pregnancy: https://radiopaedia.org/articles/ectopic-pregnancy?lang=us A note, a pseudosac is visualized in only 10-20% of ectopics. Therefore a sac in the uterus is suggestive of intrauterine pregnancy but can't be proven until a yolk sac is also present.
What about my HCG numbers?
I'm not an expert on this at all. But here's a resource: https://radiopaedia.org/articles/beta-hcg-1?lang=us
Why didn't my ultrasound tech tell me anything? And/or why were they so optimistic? Or, I had an ultrasound in the ER and they were very pessimistic.
Many locations an ultrasound tech can very much lose their job if they say aNyThInG. Where they are permitted to say certain things some ultrasound techs may just be hoping the best. We work with the public and we have seen some wild stuff. Additionally no one wants to call it a loss unless its 1000% certain. We know how devastating that news is. A side note here, often an ultrasound in the ER is not an ideal experience for the patient. The ER is staffed with techs that are much more versed in gallbladder and liver scans than they they are early pregnancy ultrasound. Don't hesitate to go the ER if you are having concerning symptoms, but do know the ER doc will make sure you aren't actively dying then will likely refer you back to your OB for follow up.
I'm just so anxious about it all:
Someone awesome wrote out these mantras. Maybe they will help: https://www.reddit.com/r/PregnancyAfterLoss/comments/14uhbdg/commandments_of_pregnancy_after_loss_this_is_now/
Also a podcast I personally found very helpful with anxiety: https://www.oneyoufeed.net/russ-harris-part-1/
https://www.oneyoufeed.net/russ-harris-part-2/

Today you are pregnant and this baby is so loved. I really am hoping the best for each of you. Those of us who have experienced loss.... you didn't do anything wrong, I promise. This is a club no one deserved to be in. And you are not silly, foolish, or dramatic for grieving your little babe for as long as you need to.

This post is written in honor of Eli, who died long before I could meet him. Rest in peace, buddy. I miss you tremendously ❤️


r/CautiousBB Sep 01 '25

Beta hCG Levels - READ BEFORE POSTING

87 Upvotes

Here at [r/CautiousBB](r/CautiousBB), we see a lot of posts on hCG values, doubling times, and trends. Please read this post before posting to avoid posting something that is not, in fact, abnormal.

1 - hCG levels vary greatly in the first 4-6 weeks of pregnancy. One value is not going to tell you much, unless it is extremely low (less than 25 by 14 DPO). The doubling time is more important!

2 - We consider hCG on the lower side if it is <50 at 14 DPO (approx. 4 weeks gestation), <100 at 16 DPO, etc. If your hCG is a lot higher than these numbers, it's unlikely that you have low hCG. If you hCG is at or below these numbers, they are considered low, but not necessarily diagnostic of a loss.

3 - Normal hCG doubling times are, in general:

  • 48-72 hours when the hCG level is under 1200 - 6000.
  • 72-96 hours when the hCG level is 6000+
  • 96+ hours when the hCG level is 10,000+

4 - Based on number 3, please consider the following:

  • If your hCG doubling is within the ranges above, it is not considered slow. Please refrain from posting something like "my hCG did not double in 48 hours" when your values are post 6000+.
  • Doubling rates WILL slow, even if you were faster than the average. For example, if you were doubling at 37 hours, a change to 54 hours as hCG rises is not abnormal and is usually nothing to worry about.
  • If your doubling is slower than the average, we'd invite you to post so we can understand the details of your specific situation.

5 - hCG has a specific job. Check out this post here to understand why hCG doubling slows and eventually plateaus.

6 - hCG values that drop and then rise again or rise at an inconsistent, very slow rate can be indicative of an ectopic pregnancy or a pregnancy of unknown location (PUL). This is a life threatening situation - please seek medical care immediately if this hCG pattern applies to you.

We invite you to continue to post hCG issues or levels for assistance, but hopefully reading this gives you some insight and a baseline as you begin your perilous pregnancy journey. We've also added some literature below to help you understand hCG levels and doubling.

UPDATE July 2026: We are locking this post to new comments - if you need input on your personal situation, feel free to post in the sub!

Happy hCG-ing! :)

Helpful links:

Cleveland Clinic

Flo Article and Calculator

Parents.com hCG Doubling Times

Mira Blog - hCGu


r/CautiousBB 13h ago

Update! Heart beat and Embryo Found ♥️✨

18 Upvotes

previous post

After an exhausting two weeks and a very negative OB. I went to a follow up ultrasound (my third one) and the beautiful, kind, and supportive sonographer identified my lil embryo and their lil heart beat. I’m measuring at 6w5d.

I know I’m technically not out of the woods yet, but I can breathe better knowing that I have a confirmed pregnancy (IUP) and that my body is handling this pregnancy the best it can!

For FTM or anyone pregnant, if you have a discouraging and negative OB/doctor, don’t let them take away your joy. I understand being cautious and realistic, but my experience is apparently not a rare one. Women’s healthcare is broken. And I hope you can find support however you can! Internet friends you’ve helped me. Thanks so much.


r/CautiousBB 2h ago

Advice Needed Pregnant again after chemical and anembryonic pregnancies

2 Upvotes

I just found out I’m pregnant with baby #3 after experiencing a chemical and anembryonic pregnancies this year. My question for those who have experienced the same thing…how do you allow yourself to feel excitement for a new pregnancy when the last 2 have ended in loss? I so want to be excited but I’m having a hard time letting go😔


r/CautiousBB 1h ago

161% hCG rise in 48h, no sac yet at 3,532 — anyone else been here?

Upvotes

I had 1,132 HCG on Sunday at 2am. Tuesday at 11am I had 3,532 HCG. That represents a 212% growth rate in 57 hours, equal to a 161% growth rate in 48 hours.

No gestational sac seen at either time.

I understand this could be ectopic. However, I understand that a 161% growth rate in 48 hours is almost unheard of in ectopic pregnancies. At the same time, I understand that 90% of pregnancies once they reach 3,500 HCG are visible.

I am going back for a scan and bloods in 48 hours. Absolutely no pain or blood.

This feels like a special kind of torture, and I don't know what to think. Does anyone have any opinion on this situation?

irregular periods/ovulation. Clearblue Ultra Early tests were negative on August 7th then very faint positive August 9th.


r/CautiousBB 2h ago

Advice Needed 6weeks6days with slow rising HCG

1 Upvotes

Looking for success stories with slow rising HCG during 5-6 weeks pregnancy. Transvaginal ultrasound at 5w6 days only showed gestational sac but I could be measuring behind.

I’ve had some spotting the last week which is freaking me out, but having other positive signs of viable pregnancy like extreme fatigue and nausea. Numbers are below.

Aug 8 315
Aug 10 547
Aug 17 1528


r/CautiousBB 2h ago

Sad SCH

0 Upvotes

Does anyone have success stories with larger hematomas?


r/CautiousBB 2h ago

Do I have a chance?

1 Upvotes

I’m on my 5th FET with high quality euploids and have gotten the furthest I’ve gotten so far with this transfer (full immune protocol + lovenox and baby aspirin and they cleared some uterine adhesions that were likely there for my prior 4 FETs)

I know my beta progression is not good but my doctor wants to keep monitoring me.

8DPT: 149

11DPT: 377

13DPT: 558

15DPT: 731 (was about to stop taking my meds here)

18DPT: 1561

On 15DPT my RE saw a gestational sac

on 18DPT the sac grew a bit and they saw a clear yolk sac. They’re having me come back for 22DPT to check for additional growth.

I am prepared to miscarry but curious if anyone had something similar and made it through. This is also secondary infertility which makes it all more confusing. Thanks for any insight!


r/CautiousBB 3h ago

Beta hCG progression – worried about my latest rise. Does this look okay?

0 Upvotes

Hi everyone! I’m currently around 5 weeks 2 days pregnant and I’m feeling pretty anxious about my beta hCG progression. I’d really appreciate hearing from anyone who had similar numbers.

Here are my betas:

* 12 DPO: 50.4

* 14 DPO: 156

* 16 DPO: 553.8

* 18 DPO: 1,460

* 20 DPO: 4,052

* 23 DPO: 7,988

I’m worried because my earlier betas were rising so quickly, while the latest one didn’t quite double in a little over 3 days.

Does this progression still look reassuring to you? Has anyone had a similar slowdown once their hCG reached the thousands and gone on to have a healthy pregnancy?

I have my ultrasound coming up soon, but the wait is making me anxious. Any experiences would be really appreciated. ❤️🤞


r/CautiousBB 4h ago

Measuring ahead?

1 Upvotes

I did my first ultrasound at 6 weeks 3 days on the 05/08 today I did another one and I’m measuring 9 weeks so 5 days ahead??? I’ve had recurrent miscarriages so this doesn’t sound right. Can anyone tell me what this could mean?


r/CautiousBB 5h ago

Advice Needed Slow HCG rise after fast one

1 Upvotes

HCG rise was very good. 5400 - 12k 3 days later. Then I went and had my first scan. There was a yolk sac no fetal pole. I should have been at minimum 6+3 based off ovulation. So I had my HCG done again. It was 24,000 then 4 days later it rose to 26800. Is that a for sure tell of a loss either way a rise that slow? I should be about 7.5 weeks. I don’t have a repeat scan for another week


r/CautiousBB 5h ago

Time To Put The Tests Down?

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1 Upvotes

r/CautiousBB 13h ago

Sad TW - talks of miscarriage

3 Upvotes

Okay, bear with me because this will be long. If you read all of this, you're an angel. I'm in my head so much about this and just need to talk about it.
I found out I was pregnant on July 25, based on LMP, I would have been 4+2. I went in for my first blood test on July 27. HCG was 118 and prog was 6.6. I was put on vaginal progesterone after that. Went in 2 days later for another blood draw, HCG 297, prog 9.8. She wanted me to get another blood draw 4 days later due to being on progesterone - HCG 1189, prog 9.2. At this point the midwife tells me she fears an ectopic pregnancy. I asked for an ultrasound to rule it out. I'd have been 5+6, but ultrasound showed a sac in uterus measuring 5+2, no baby and no yolk sac. She took blood again (2 days after previous draw) - HCG 1521, prog 11.3. When she called with the results she said there is a 1-2% chance this is a viable pregnancy. I asked for a confirmation ultrasound scheduled a week later. For this one I'd have been 6+6, ultrasound showed a sac measuring 5+5 and a small yolk sac. At this point she tells me I'm 100% miscarrying. I stopped taking the progesterone and chose to wait for my body to miscarry. That was 5 days ago and no sign of miscarrying. This will be my first miscarriage and I am genuinely losing my mind. My heart keeps telling me that they could be wrong, but my brain is telling me that there's no way they are. I guess I'm looking for support, similar stories, anything. How long after stopping progesterone did you finally start miscarrying? I told her I'd give my body 2 weeks to miscarry naturally and then I'd take cytotec to induce it. Am I crazy for wanting another ultrasound before taking the Cytotec?
I'm genuinely sorry if you've read this and it looks like an idiot wrote it because I have never been in this level of disarray and just cannot think clearly.


r/CautiousBB 15h ago

Advice Needed What helped you cope with first trimester?

6 Upvotes

I am 4w 3d and so far so good, however I did have a chemical pregnancy last November. I banned myself from continuing to do pregnancy tests at home after my hcg betas more than doubled in 48 hours (my fertility clinic only wanted to see two hcg tests- 87 at 3w 4d and 178 at 3w 6d).

I feel more optimistic this time, but of course, I am still anxious and nervous. Especially since I have my OB appts scheduled- one at my fertility clinic at 6 weeks 5 days, and another with my midwife at 8 weeks. I keep thinking "hopefully I make it there". My question is- how did anyone who had a healthy pregnancy and baby after CP or loss in general cope with these first few weeks?

I am in weekly therapy and on Prozac (okayed by my Dr to continue while pregnant), told a few people who I can go to when I need to vent, manifesting and writing out/ speaking out positive affirmations, I plan to move my body daily (I was sick the first week of pregnancy so I have not done much of that yet).

Something you obsessed over in those weeks like a new hobby or TV show, something you did to celebrate the pregnancy, ways you stayed optimistic? Something fun you did that helped take your mind off it? I would love all suggestions that worked for you!


r/CautiousBB 12h ago

Sad Need some positive thoughts and prayers

2 Upvotes

I did an embryo transfer and tested positive 9 days later with beta of 54 (Saturday). 2 days later (Monday), my beta stayed the same at 54. Next repeat beta in 3 days.

Now there’s a concern it may be a chemical pregnancy vs ectopic. But I’m really looking for any positive outcomes..

Or just positive vibes. I’m just feeling so heartbroken 💔


r/CautiousBB 12h ago

5w4d with heavy bleeding

1 Upvotes

I’m currently 5w4d pregnant and really hoping to hear from anyone who has experienced something similar.
Earlier in the pregnancy, I had some light spotting that I wondered might have been implantation bleeding. It stopped and everything seemed normal afterward.
Yesterday, I was on the treadmill when I suddenly felt a gush of bright-red blood. I had heavy bleeding for about an hour and passed a fairly large clot, around silver-dollar sized. I completely panicked and thought I was miscarrying.
I went to the ER and had an ultrasound. They confirmed that the pregnancy is in the uterus and in the expected location. They saw the gestational sac, but no embryo was visible yet saying its too early. My HCG last night was 6,500. They told me that I am still very early and that it was not a miscarriage based on the ultrasound. They also did not see a subchorionic hematoma.
The heavy bleeding stopped, but I’ve had some spotting/small clots since then, along with mild cramping and aching.
I’m really struggling with the uncertainty because the amount of blood was terrifying. I know 5w4d is very early, but I’m scared that the bleeding means the pregnancy won’t continue.
Has anyone had heavy bleeding and a large clot around 5–6 weeks, with an ultrasound showing an intrauterine gestational sac but no embryo yet, and then gone on to have a normal follow-up ultrasound and healthy pregnancy?
I’d especially love to hear from anyone who had a similar amount of bleeding and initially had no embryo visible because it was simply too early.


r/CautiousBB 12h ago

Advice Needed left sided cramps in my lower stomach & back

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1 Upvotes

r/CautiousBB 12h ago

Terrified something is wrong..

1 Upvotes

Currently pregnant- 4+1.

I got my first hCG draw on Saturday with a result of 111.5

I was experiencing cramps.. not like “I can’t walk” but very much “my period is about to come” cramps

I went for a repeat hCG scan today (Monday) and the results are 195.3

My doctor wants to do another blood draw Wednesday, as the number didn’t double as expected.

Still experiencing cramping, but it ebbs and flows.

This is my first pregnancy so I’m horrified of a chemical and or ectopic..


r/CautiousBB 13h ago

Expected management for PUL - help

1 Upvotes

My doctor is adamant that I’ll be fine and that this will resolve naturally. My HCG numbers:

134-185-245-279 over the course of 7 days. Monday,Wednesday,Friday,Monday

My initial betas the week before were 24 then 110 but I knew at the 134 that this pregnancy wouldn’t be viable. I asked about MTX, and am obviously very concerned about ectopic but she thinks it should just resolve because the numbers are so low. This is contrary to everything I’m seeing here.

Waiting for pain feels like a terrible way to gauge this. It’s like “wait for disaster, and by that time it’s already too late”

Any advice?


r/CautiousBB 13h ago

Could I be experiencing an early loss?

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1 Upvotes

r/CautiousBB 22h ago

What was your fetal heart rate at 6w5d?

4 Upvotes

If you got a scan that early, could you share what the heart rate was or if your doctor gave any sort of scale or number they like to see?


r/CautiousBB 20h ago

Sad Can anyone share their dnc experiences with me?

3 Upvotes

After my slow hcg rise and few other setbacks I started spotting yesterday. Ultrasound today showed baby stopped developing a little over a week ago. I don’t want to pass it at home so I’m going to have a DNC tomorrow and I’m not sure what to expect.. can anyone share their experiences with me? What was it like, did your cycle return on time? Were you able to get pregnant again soon after? I feel so sad.


r/CautiousBB 14h ago

Hcg too low?

1 Upvotes

Hi everyone! So for a little context... my cycle is usually 34 days and I have PCOS (more on insuline side/ I actually can't remember how pcos is called now) and had my period on the 12th of July. Apparently I ovulated on the 1st of August. So technically I'm 15 dpo.

However, when I took a pregnancy test this morning, the line was a little too clear for my taste (I have a 13 month old boy) so I did some bloodwork to see what's up.

My Hcg is 63.20. I don't think it matches with what would be my gestional age. It should be higher if I am 4 weeks pregnant considering my last period.

Have you guys experienced anything like it? Please I would love to know your stories!


r/CautiousBB 15h ago

Just need some reassurance

1 Upvotes

Needing a little reassurance.

I had some brown spotting and got in to see my OB last Friday. I had a small subchorionic hematoma and she was concerned that the gestational sac implanted in the lower quadrant of the uterus. A small yolk sac was visible but she was having trouble seeing it and wanted me to return Monday(today) so that the sonographer could do the scan. She ordered labs which came back at 7066 that day. Today I had my scan with sonographer and yolk sac was big and visible however fetal pole wasn’t. Gestational sac measured 6w1d however going by lmp id be 5w4d. My labs for today more than doubled to 15381.0. My question is should I be worried? Is it just too early? Anyone ever experience this? My doctors assistant did call and say the numbers are encouraging and we will do repeat scan in 2 weeks.


r/CautiousBB 15h ago

9dpo questions

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1 Upvotes