Birth body weight to length ratio

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My (and my sister's and brother's) birth was not premature. But my birth weight was very low, sister's low. Brother's was (slightly above) average. All three children have birth length above average, especially my brother. He had 57 cm (well above 98th percentile, BLQ about 140 In my opinion) and 3600 g (about 62nd percentile, BWQ about 106). Gap is large (about 35), but even his birth weight was larger than average (which is about 3350 g). He looks more NT than me, my sister and my mother.

Brother of my mother had birth weight about 3750 g (which might be very slightly above 75th percentile, BWQ about 111) and body length 53 cm (about 85 - 97th percentile, BLQ about 116 - 128). Gap is much lower (about 5 - 17) than for me, my sister, my mother, my brother and probably my father (he had 2800 g (slightly above 10th percentile, BWQ about 82) and birth weight might be above 52 cm, I do not know birth length of my father ). It is interesting.

My grandson was the tallest baby the paediatricians had ever seen in the children's specialist hospital.

Now at 17, he is 6 feet 10 inches and growing rapidly. He is very definitely on the spectrum. Plays basketball and is climbing the ladder. Hopes to go professional one day.

Both of my kids fell in the 50-75% range. But they both had head circumference 95%+.

I couldn't vote twice (once for each kid), but if I could have, it would have made the n for below 50% equal the n for above 50%

http://www.wskfit.pl/PDF/artykuly/14005.pdf

Weight-length relations of Polish newborns as assessed by perinatal measurements (in Polish)

Data for 2255 newborns born on time (between 37th and 42nd week of pregnancy) and without congenital or developmental disodrers in 13 hospitals in Warsaw from V 2013 to VII 2013:

Girls:
- n = 1041,
- body length: 54,3 cm (SD: 2,7 cm, results: 44 - 63),
- body weight: 3,37 kg (SD: 0,47 kg, results: 1,80 - 4,93)

Boys:
- n = 1214,
- body length: 55,0 cm (SD: 2,8 cm, results: 42 - 65),
- body weight: 3,51 kg (SD: 0,49 kg, resuls: 1,53 - 5,32)

My body weight (I was born on time and without congenital or developmental disorders (Polish: "wady", literally it is translated better as "flaws" or "defects") is about 2,75 SDs below average (3,55 kg - average for more than 1200 boys from this work, SD - 0,49, so it appears to be about 0,3th percentile according to SDs). I had also very low "weight-length ratio" - well below 3rd percentile, maybe even below 0,5 (it appear to be also about 2,75 SDs below average). I had 2150 g and 53 cm. Body length in Poland is overestimated due to other method of measuring, so most of Polish newborn fall below 5th percentile on the WHO birth weight-length chart. But I appear to be still much below 3rd percentile when WHO method of body length measuring would be used.

But my brother had 3600 g and 57 cm and has average "weight-length ratio" (50th percentile) and is birth weight is about 58th percentile and he is NT (at least in my opinion). Father has 2800 g, mother 2800 g and 56 cm, sister 2650 g and 53 cm - their birth weight is about 1,5 (sister) - 1,2 SD (mother) below average. Sister has "weight-length ratio" at about 3rd percentile, mother even somewhat lower. Value about 1,5 SDs below avearge appear to be just about 7th percentile... And 1,2 SDs below it - about 12th percentile. Father has about 1,4 SD below average (about 8th percentile).

Maybe it is genetic? And it is associated with "neuroatypicality"? For me it appears to be associated with it. And why brother is other? Mother, daughter and me were at about 3rd percentile or below it, but brother was very average and normal...

My mother appears to be about 12th percentile of birth weight, father about 8th... Both have birth weight below average, but did not have LBW (less than 2500 g). My sister was closer to LBW range, but still above it (2650 g). Brother of my mother had 3750 g (appear to be about 69th percentile, about 0,5 SD above average for boys in http://www.wskfit.pl/PDF/artykuly/14005.pdf) and 53 cm (weigth - length percentile is very high - above 90th, nearly 94th in my opinion), according to his mother.

BWP and BLWP product ((birth weight percentile)*(birth length-weight percentile)) for:
- my mother's brother is 69*94 = 6486,
- for my brother is 50*58 = 2900,
- for my mother 12*2 = 24,
- for my sister 7*3 = 21,
- for me about 1*0,3 = 0,3

Gaps are really large. Between me and my brother it is about 10000, but we have the same parents... And the difference in "mental traits" is obvious... Low BWP*BLWP may be a trait of PDD, such as speech delay (I had not speech delay despite it). Mother and (especially) sister may appear to carry a "broader phenotype" of a PDD, sister maybe even have a (very) mild form of my PDD.

Product of birth weight percentiles for my mother's brother and my brother is 69*58 = 4002 (10 000 - maximum, so it is 40,02% of it), product of birth weigt percentiles of my parents is 12*8 = 96 (0,96%). It is low value - both parents had birth weight below average. But his younger son had normal birth weight and is not "aucorigic" ("PDDish" or "PDD-like"), is most "neurotypical" person in my ome for me.

Interesting topic. I hadn't really thought about it before, so I hadn't looked into it.

54.6 cm long, which is high 99th percentile.
3,657 gram, which is 72nd percentile.

But according to the "WHO 0-2 Years: Weight For Length Percentile" charts, I was in the first percentile.
Apparently, my weight was about 816 grams below average for a baby of that length.

In my early childhood I was pretty tall and skinny for my age.
That changed later when I started to have weight issues.

I was born in 39th week with weigh of 3900g and length of 55cm.

According to this website http://www.justmommies.com/articles/inf ... ator.shtml my results are:

Length for age is in the percentile > 97th
Weight for age percentiles 75th - 90th
Weight for length percentile 3rd - 5th

Apparently I was huge and my weight couldn't make up for this. Not a big deal though. I am still high and slim(BMI 18,5) so perhaps its just my natural body build.

I have found that percentiles, when an infant is very young, frequently are meaningless in determining the final height/weight of a person.

I was actually born late, so I was within normal ranges (8 pounds and 2 oz). I don't know the exact number of inches, but I've been told it was normal too (even though I've ended up being rather petite as a young adult).

As someone already mentioned, birth weight/length as an infant is likely to be meaningless when comparing it to adult height. So it would be very hard to prove a connection between birth weight/height and autism, considering you have to factor in so many different variables. (Though I'll admit that it's interesting that so many people had low birth weights.) If a child is premature (for whatever reason), then they're obviously going to have both low birth weight and height, but that can't determine what someone's genetic potential for adult height will be.

As for the variables you have to consider, there are the outliers like children who are born with endocrine or hormonal disorders (but aren't diagnosed until later or do not develop it until toddlerhood) and end up being put on hormonal therapy and such to correct the issues (and thus there's a discrepancy between infant height/weight and adult height and weight), mother's height/stature (some petite women do tend to have naturally small babies), the condition of the mother's uterus and other reproductive parts, the mother's overall health including any conditions, if low birth rate is genetic and why (since someone brought up that question), the fact that premature children are often underweight or relatively small for the rest of their lives (at least according to my mother who is a retired nurse - I have a cousin that was born premature and it's definitely been true for him), etc... It's interesting, but it'd definitely be hard to prove. It would be more worthwhile to look at a specific variable IMO.

Yup. I only ended up being 178 cm tall.
My weight, on the other hand has been as high as 113 kg and as low as 70 kg as an adult.

My younger brother, who was smaller as a baby, is almost my height already (about 5 cm shorter) and he's only 12 years old.

Here is a calculator of weight-length percentile (Baby Infant Growth Chart Calculator WHO 0-2 Years: Weight For Age Percentile):

http://www.infantchart.com/infantweightlength.php

I read that birth lengt measurements (at least in Poland) give too large length due to other method that used to make WHO charts. Most Polish newborns will fall below 5th percentle due to it, such as in this work: http://www.wskfit.pl/PDF/artykuly/14005.pdf (I gave link to it earlier in this topic). I had 2150 g and 53 cm in health certificate (Polish: książeczka zdrowia). Even when I subtract 6 cm from 53 cm (receiving 47 cm), I still have very low percentile (just 0,2!). In weight chart (www.infantchart.com) I have also just 0,2th percentile. The product of these two percentiles (birth weigth percentile*birth length-weight percentile (BWP*BLWP)) is very low - 0,2*0,2= 0,04. It is even below 0,1. And the maximum is 100*100 = 10 000. So I had below 0,001% according to WHO chart... It means obvious asymmetric hypotrophy. Despte it, I had 10 points in Apgar scale. My birth was not premature (on time, as stated in my health certificate).

My brother had 57 cm and 3600 g in health certificate. Birth weight percentile - 69,5. When we subtract 6 cm from 57 cm, we receive 51 cm and it will give 57,9th percentile. BWP*BLWP = 69,5*57,9=4024,05 (40,2405%). It is about 100 000 times larger than my BWP*BLWP according to www.infantchart.com.

My sister had 53 cm and 2650 g in health certificate. BWP - 8,9th. When we subtract 6 cm from 53 cm, we receive 47 cm and it will give 26,8th percentile. But 53 cm and 2650 g gives much lower BLWP accordng to the charts for Polish newborns from http://www.wskfit.pl/PDF/artykuly/14005.pdf (it would be about 3rd percentile, so it means really low BLWP, not in lower range of average). It is large difference. 48 cm and 2650 g gives 9,7th percentile, 49 cm and 2650 g gives 2,3th percentile. So how large would be her birth length according to WHO standards? It appears that it was larger than 47 cm, maybe between 48 cm and 49 cm (maybe even closer to 49 cm). But my brother has almost 50th percentile on chart from http://www.wskfit.pl/PDF/artykuly/14005.pdf. On WHO chart he has 57,9th percentile when we subtract 6 cm from is birth length from birth certificate. So how large is overestimation of Polish birth length measurements in comparison to WHO standards?

I don't know.But I don't think it would be whole 6cms. If I subtract 6 of my 55cms I am getting 25th-50th in length and > 97th in weight/length ratio which doesn't fit what my mom said about me. Apparently I was visually a really long and slim compared to other newborns. I had "adult proportions".
Btw. My body weight to dropped over 23% within the 1st day of my life (from 3900 to 3000g within 24h). Apparently I was throwing up water for a few hours after delivery and my body lacked oxygen. My mom thinks its her fault because she didn't know how to give birth to me (apparently I was "trying to get out" a few times but she was holding me in, unaware how to push) and she thinks it has something to do with my AS.

Your symptoms appear to be associated with "classic" form of AS, which is probably genetic and is looks as significantly related to "typical" autism. Your type of AS may even be not related to mine at all. So large (-900 g in 24h) drop of newborn's weight after birth is hard to explain to me. Drop of birth weight should not be larger than 10%.

In my family mother had birth weight about 16th percenitle, father about 12th, sister about 9th, I below 0,5th (it may be associated with my "neuroatypicality") on WHO chart. But brother's is about 69,5th percentile. Lower birth weight appear to mean larger "neuroatypicality". Sister may appear to me as having a very mild for of my form of AS, which is much less "weird" than mine. I suppose that the sister of my mother's mother might have profound autism, because grandmother said me that she did not speak, has something which looks as self-harming behaviors and died wen she was only 8 years old. Grandson of one of my grandmother's brother appears to have an ASD (more apparent than my AS), because my grandmother said that he had speech development problems and was afrad of going to new buildings (or something similar).

I find another growth chart: http://www.infantchart.com/olsenweightforage.php

Preterm Infant Growth Chart Calculator
23-41 Weeks: Weight For Age Percentile

This app uses tables and data solely based on United States premature babies. Caution should be used on all charts for the twenty-third week for percentiles at or below the 3rd percentile and at or above the 97th percentile. This is due to a low population size. For the twenty-fourth week, the data is skewed to the left for all head circumference data. See the reference below for more information.

This calculator provides your baby's weight percentile based on age. The percentile shows how your infant's weight compares to other infants. The percentile tells you what percentage of babies weigh less than your baby. For example out of a sample of 100 babies, a percentile value of 40 percent means your baby weighs more than 40 babies and weighs less than the other 60 babies.

A percentile of 50% represents the average or mean weight. A value below 50 percent means a baby weighs less than the average. A value greater than 50 percent means a baby is above average. This does not mean your baby is overweight or underweight. A doctor or physician should be consulted to determine weight status.

Birth "on term" is from 37th to 42nd week of pregnancy. I entered 2.15 as a weight when gestational age was 37 weeks and the result was 3,8th percentile (still really low). But I was born on term, as it is written in ealth certificate.

In weight chart for ethnic Chinese children (http://www.infantchart.com/chinese0to18weightforage.php) (data for the age 0.0 months - at birth):
- 2.15 kg for males is on 0,0 percentile
- 2.8 kg is on 8,4th percentile,
- 3,6 kg is on 75.2th percentile,
- 3,75 kg is on 85,1th percentile.

For females:
- 2,65 kg is on 5,3th percentile,
- 2,8 kg is on 12,5th percentile.

Oh! Wait. I know what is wrong. The "3900" at birth is not 3900 but 3200. I just realized the handwritten "9" in my health book looks almost like the handwritten 2 in Apgar table (which could be read as 9, double zero, weird 8 or infinity symbol as well but since the scale is 0-1-2 it couldn't be any of those so it must be a weird 2 which gives 8-9 Apgar points).
So weight loss was only 200g, 6% of 3200g. Everything is fine.

Doctors should honestly work on their handwriting... What kind of 2 is it anyway?

Last edited by Kiriae on 31 Dec 2014, 11:37 am, edited 2 times in total.