ivf babies and low birth weight

I am going for a scan tomorrow to check my babies weight, as it doesn't appear to have grown much in the last 3 weeks ( going by fundal height measurements, has been 33 cm since 34 wk visit and again at 36 week visit, fluid level looks good).
I suspected the baby wasn't very big as I had been measuring at home and being a midwife I know what a 36 wk baby feels like to palpate in the womb. ALthough my tummy feels like it is getting bigger, the actual baby doesn't ( too many xmas treats?? :D)
I had a scan at 32 weeks and it was on the 60th%ile and a good weight, no problems with fluid, blood flow in cord etc, I also get great movements so not too stressed about that, and if there is any major concerns tomorrow I will just ask to be delivered as I'm over 36 weeks now and not going to push my luck after the hell it took to get here.
I know ivf babies are at greater risk for low birth weight but I don't really understand why? Is is maternal age? DH and I are not small people we are both tall and were reasonable sizes at birth, so its not a genetic smallness.
Not going to google as I don't want to start freaking myself out.

Not really sure what I am asking here, but any thoughts on low birth weight with ivf??

Hey Saffy sorry to hear you're a bit stressed about bub. My DD was born at 38w2d and weighed 3.4kg, so no low birth weight there! Current bub measured 1.14kg at 27w5d and OB told me that 1.2kg at 28w was the average. So this one is slightly under at the moment.
Personally I have no thoughts on why IVF bubbas would have lower birth weights. It just seems like an odd concept!! Interested to see other replies.

Saffy has everything else been well during your pregnancy ie no blood pressure? Statistically they do say IVF babies are smaller. As you know I too am a midwife and not a small person 178cm and had my 2nd daughter at 36+3. We were expecting 5lbs but out she came at almost 8lb. I'm struggling to reply on my iPod so will pop back later

Yeah BP has been absolutely fine the whole way, no other dramas- not too stressed anyway but just more curious.
I will say that at the 34 week measurement baby was lying transverse and now it is cephalic with head 2-3 above brim, so maybe it is just curled up well. Just surprised my fundus is only 33cm ( I have checked it a number of times lol). I've only really put on 2 kg in the last 6 weeks also, but I have put on a total of 13kg the whole pregnancy, so thats enough!!
Will know more tomorrow, thanks girls xx

I quizzed FS about this (yep, I was one of "those" patients!)

Her take was that IVF bubs aren't from "normal" parents usually. So there are factors like maternal age, and also all the other reasons that getting pg in the first place was harder etc. She also said that she had once had some numbers crunched on the clinics outcomes where it was male factor infertility and when they did that there was no statistically significant difference in birth weight to a natural conception so my clinic decided that it wasn't the IVF as such that was the factor in lower birth weights, rather the other factors.

Does that make sense? Help?

while I didn't go through ivf I did have q similar thing happen with my weight and fundal measurement. from about 35 weeks on my belly didn't grow at all. not 1cm, but having said that she was engaged from then on. I knew I was getting bigger, but for some reason didn't grow? :dunno: I lost A LOT of weight (~25kg) in the first trimester and didn't start gaining weight until about 20 weeks.
I gave birth at 39+3 after spontaneous labour and DD was 3.24kg. not huge, but a nice size :) I had a scan about 3 days before I went into labour (hossie was worried I wasnt growing) and they predicted she was about 3.15kg or so, and thus within a normal range)

i guess what im trying to say is possibly if it feels like bub is growing, could it be that they have engaged at all?

DD#1 was naturally conceived at age 30 and born at 41+2 at 7ld 5oz and DD #2 was conceived via IVF age 36 and born 39+5 at 8ld 10oz - so for us that statement is incorrect. I will note that I had GD with DD#1 that was diet and exercise control.

I didn't use IVF, Saffy, but I do have lower than average weight babies. (2.83 kg and 2.56 kg) My babies tend to measure normally (by fundal weight) up until about your stage. The pg with DD2 I never measured above 36 weeks fundal height, and by the end it actually dropped. It was just because the bubba dropped into position and went further down, ITMS. She def continued to grow, but every extra cm in growth must have been accounted for by a cm drop into my pelvis. Bubs changing position will also affect fundal height measurements.

I thought I'd be much bigger second time around and I had put on more weight by 30 odd weeks, it just slowed down after that. I'm about average height, DP is tall (6 ft 2), but I'm only petite build and I guess that's the size my body grows to make birth easy. :dunno:

PS I hope you don't mind me responding here, Saffy, even though I don't usually trot into the LTTTC areas, since I have no right to be here. Just thought the low birth weight thing from non-IVF might help settle your mind. I'll trot back out now!

With DD my fundal height measured on average at every check up and she was born at 38 + 2 and weighed 3.12kgs (7lb), I only put on 6kg's for that pregnancy.

Obviously the twins are a bit different as they are generally smaller babies anyway, but they were born at 37 + 4 and weighed 2.63kg's (5lb 8oz) and 2.77kg's (6lb 1oz) and my Ob was very happy with the weights, I only put on 13kg's for that pregnancy.

DH was over 8lb when he was born and I was 7lb 3oz born 4 weeks early so I always thought I would have 'chubby' babies but I had skinny one's but they have made up for that now with all 3 being in the 50th to 75th percentile for both weight and height for there ages.

Maybe bubs has already started descending or is preferring to stay curled up at this stage.

What Muppity said!

It's not so much the IVF that 'causes' low birth weight, but the reasons that the assistance was required in the first place. Don't freak out - don't google stuff! Dr google has a lot to answer for.

My two are IVF babies - DS was 2.6kg but was born at 36w3d, DD was 3.4kg born at 39w5d so had DS been closer to the 40w gestation he would likely have hit the 3+ kg mark. 'Average' newborn weight is 3.5kg

I have quite a few friends who have IVF babies, all the smaller ones were born 2-3 weeks before their due date so it was really gestation rather than the IVF factor.

Both my boys were IVF and were average weight.

my first ivf bub was 3.6kg and my second was 4.6kg (yes you read that right, 10 freak-en pounds 3 of chubby icsi/ivf love). I also hadn't heard low birth weight is an issue. hope all is well with you both!!

I've had a quick look through the uni database and there seems to be a small suggested link between maternal ovarian stimulation and lower birth weights. So if IVF is done through a frozen transfer then there is no difference in birth weights, equally if the pregnancy results from egg donation as the donor is the one who went through ovarian stimulation. However the link is not universally accepted yet (from what I can understand) but the main take away point is that most babies, whether through IVF or not, are born healthy.

My understanding is also that there is no demonstrated link between IVF itself and risks/adverse outcomes in pregnancy, but there is a correlation.
I would be interested in reading anything that actually suggests a link, however, Trav :)

I had thought the main determinant of birth weight was placental function?

My babies were 4.3kg and 4kg, which proves nothing, but anyway I hope all is well with you two, also!

It's one of those suggested links at the moment MadB that needs more research, and there are as many articles saying it is unsubstantiated as those which suggest it is true. If I can find anything solid I will post a reference :) The more I look though, the more articles I am finding that say that although birth weights may be marginally lower as a general trend, this is not pathological and there is no known reason why.

havent had a chance to read the other responces, but always measured behind and Spock was a healthy 3.8kg. I haven't heard the risk of being LBW, I have heard that they tend to be born earlier (another theory of the guess date rather than due date because you know exactly when conception happened with ivf), but Spock was a week and a half over due so who knows =P
hope all goes well with your scan =)

I wonder if one partial contributing factor might be the x percentage of OBs who insist on inducing early with IVF pregnancies?

Thanks everyone for your input! Interesting re the stim cycles having something to do with it. Jury is still out by the looks of it.

My scan went great, all normal, baby must have just been curling up tight when measured, as it around the 50th%ile for weight ( 2.7kg) and all normal so full steam ahead there. Looked really cute with chubby cheeks!

Special thanks to Traveller for coming and holding my hand through the scan :D

That's really great to hear Saffy!!

yay thats great!!

Good news!

Hey Saffy, congrats on your pregnancy!!! We are due within a few days of each other :D. Glad to hear all is well with your bub and the scan. I've been fascinated to read this thread. I hadn't heard of some of these possible outcomes due to IVF. I just figured once you got pregnant you were like anyone else in the community and your pregnancy would be treated the same. I remember when I was waiting for my first very overdue bub to make some moves to come into the world, a random consulting Ob was amazed that I, an IVFer/LTer wasn't freaking out about getting my baby out ASAP. According to him, we can tend to be more nervous and want bub out sooner.
DD was 4kgs and 17 days overdue, but until I read Traveller's post I hadn't given any thought to whether, because I used an egg donor this affected the outcome. Who knows LOL! Best of luck with everything over the next few weeks.

Hi Dusty, thanks!
Thats funny because I do remember you going overdue and getting stressed for you ( as a midwife my only experience of ivf patients was most of them having elective cesears for anxiety!) but of course all was good. I didn't get the gist of the donor bit- did it mean the babies weren't any smaller cos the donor had the stimulation- so its the ovarian stim that causes the smallness not the baby?? Anyway, doesn't matter cos my baby is normal sized.

Funnily enough, my sister just had her first baby last night and it was 4.6kg! Not ivf obviously!! One extreme to the other. My obstetrician will be glad I had another growth check when she hears that!

congratulations Auntie Saffy, I was thinking of your sister and wondering how she was going :)