PREMATURITY AND LOW
BIRTH WEIGHT IN DOWNS. AN EPIDEMIOLOGICAL INVESTIGATION ON 510 SUBJECTS.
Renato Cocchi, a neurologist and a medical psychologist.
Affiliation: CTR, via
F.lli Cervi 59E, 42100 Reggio Emilia (Italy)
Abstract
As derived from the
same series of 510 Down Ss, two subsamples were extracted, the first with
prematurity (69 Ss, 53 M + 15 F, M/F ratio = 353.33; normal distribution of the
chromosomal diagnoses) and the second one with low birth weight (56 Ss, 39 M +
17 F, M/F ratio = 229.41; statistically normal distribution of the chromosomal
diagnoses). So prematurity and /or low birth weight do not directly depend on
the chromosome 21.
Prematurity and low
birth weight in Down syndrome Ss are known events but not so frequent as told.
In our series they occurred respectively in 13.34% as prematurity and in 10.98%
as low birth wight. Between them, thirty-two (6.27% of the whole series) had
both these risk factors. Prematurity showed statistically significant male
prevalence when alone (.0002) or with contemporary presence of low birth weight
(.032). This male prevalence seems a fully new finding.
Key words: Down syndrome; prematurity,
low birth weight, epidemiology, stress, male prevalence, ..
Home Page
/ / / Pagina
iniziale
Since years, I explored an electronic
database where I collected information and symptoms referring to first 510
subjects with Down syndrome. Among others, I did epidemiological investigations
on cerebral palsy (1), easiness to upper respiratory tract infections (2),
toilet habits (3), hyperkinesis (4-5); depression, (6), combing difficulty (7),
sialorrhea (8), balance (9), the joint laxity / hypotonia (10-11) and the
tongue protrusion (11-12),
Now I want to check the prevalence of
prematurity, low birth weight or both these risk factors in this cohort of Down
syndrome subjects.
Materials and methods.
This investigation used my clinical cards
referring to a consecutive series of home reared and home living Italian Downs
as seen in outpatients' clinic by myself since 1979 to 1993. Psychotic
subjects' cards were excluded.
During their 1st consultation I recorded the
gestational week at delivery and the weight at birth, as I checked on discharge
cards of the obstetrics hospital or as the parents told me.
From all cards I collected:
- the gender;
- the chromosomal diagnosis;
- the age at 1st consultation;
- the gestational week at delivery;
- the birth weight.
I statistically processed data by gender,
chromosomal diagnoses, prematurity, low birth weight or both these two last. I
applied Chi Square Test, when suitable.
Results.
The data derived from the 510 clinical
cards, drove to a first selection of 452 cards suitable for this investigation and
the related data appear in the tables that follow.
Tab. 1: Epidemiological data of the whole
series.
|
Nr. Of Ss |
510 |
100.00% |
|
Males |
292 |
57.25% |
|
Females |
218 |
42.57% |
|
M/F ratio |
133.94 |
|
|
|
||
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
461 |
90.39% |
|
Mosaicisms |
16 |
3.14% |
|
Translocations |
16 |
3.14% |
|
Unknown, only clinical diagnosis |
17 |
3.33% |
|
|
||
|
Age at 1st consultation (months) |
|
|
|
Range |
6-510 |
|
|
Average +/- SD |
71.37 +/- 69.71 |
|
As we may see in the table 1, the M/F ratio
appears poorly different (133 vs 135) from what we know for Italian newborn and
alive Down children (13). Even the distribution of the chromosomal diagnosis, meets
the ranges of variability for Italian and international samples (13-15).
For these reasons, we may think the sample
here investigated as representative of at least the Italian population of
Downs.
Tab. 2: The gestational week at delivery
(normality: 37-42 weeks).
|
Gestational week at delivery |
No. of Ss |
% |
|
32 |
2 |
0.39 |
|
33 |
3 |
0.59 |
|
34 |
8 |
1.57 |
|
35 |
7 |
1.37 |
|
36 |
48 |
9.41 |
|
Total of premature deliveries |
68 |
13.34 |
|
|
||
|
37 |
33 |
6.47 |
|
38 |
62 |
12.16 |
|
39 |
24 |
4.70 |
|
40 |
228 |
44.71 |
|
41 |
13 |
2.55 |
|
42 |
10 |
1.96 |
|
Total of normal time deliveries |
402 |
78.82 |
|
|
||
|
43 |
8 |
1.57 |
|
44 |
1 |
0.20 |
|
Total of postmature deliveries |
9 |
1.77 |
|
|
|
|
|
Datum not recorded |
64 |
12.55 |
|
General total |
510 |
100.00 |
As we can see in the Tab. 2, premature
deliveries account for 13.34% of the whole series. In first three years I was
concerned with Down syndrome Ss, I did not record this parameter, and I could not
integrate it later.
Tab. 3: Epidemiological data of the
subsample (68 Ss)with prematurity (<37 weeks of gestational age).
|
|
No. of Ss |
% |
|
|
68 |
100.00 |
|
M |
53 |
77.94 |
|
F |
15 |
22.06 |
|
M/F ratio |
353.33 |
|
|
Total sample:510 Ss |
|
|
|
M |
292 |
57.25 |
|
F |
218 |
42.57 |
|
M/F ratio |
133.04 |
|
|
Chi Square for gender = 9.828 with 1 df and p = 0.002 |
||
|
|
||
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
62 |
91.18 |
|
Mosaicisms |
1 |
1.47 |
|
Translocations |
3 |
4.41 |
|
Only clinical diagnosis |
2 |
2.94 |
|
Total sample:510 Ss |
|
|
|
Standard trisomy 21 |
461 |
90.39 |
|
Mosaicisms |
16 |
3.14 |
|
Translocations |
16 |
3.14 |
|
Only clinical diagnosis |
17 |
3.33 |
|
Chi Square for chromosomal diagnoses = 0.895 with 3 df and p = 1.000 NS |
||
The Tab. 3 shows a very interesting datum.
Males seem to have a statistically significant more easiness of premature
births.
Tab. 4: Birth weight (normal: >= 2500
grams).
|
Weight at birth (grams) |
No. of Ss |
% |
|
<1500 |
1 |
0.20 |
|
>1499 and <2000 |
9 |
1.76 |
|
>1999 and <2500 |
46 |
9.02 |
|
Low birth weight, total |
56 |
10.98 |
|
|
|
|
|
>2499 and <3000 |
168 |
31.38 |
|
>2999 and <3500 |
120 |
23.53 |
|
>3499 and <4000 |
53 |
10.39 |
|
>3999 and <4500 |
16 |
3.14 |
|
>4499 |
4 |
0.78 |
|
|
|
|
|
Datum not recorded |
93 |
18.24 |
|
Total |
510 |
100.00 |
As we can see from the tab. 4, low birth weight
accounts for 10.98% of the whole series. Even here, in first three years I was
concerned with Down syndrome Ss, I did not record this parameter, and I could
not integrate it later.
Tab. 5: Epidemiological data of the
subsample with low birth weight.
|
|
No. of Ss |
% |
|
|
56 |
100.00 |
|
M |
39 |
81.08 |
|
F |
17 |
18.92 |
|
M/F ratio |
229.41 |
|
|
Total sample:510 Ss |
|
|
|
M |
292 |
57.25 |
|
F |
218 |
42.57 |
|
M/F ratio |
133.04 |
|
|
Chi Square for gender = 2.699 with 1 df and p = 0.10 NS |
||
|
|
||
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
49 |
87.50 |
|
Mosaicisms |
1 |
1.79 |
|
Translocations |
4 |
7.14 |
|
Only clinical diagnosis |
2 |
3.57 |
|
Total sample:510 Ss |
|
|
|
Standard trisomy 21 |
461 |
90.39 |
|
Mosaicisms |
16 |
3.14 |
|
Translocations |
16 |
3.14 |
|
Only clinical diagnosis |
17 |
3.33 |
|
Chi Square for chromosomal diagnoses = 2.653 with 3 df and p = 0.650 NS |
||
Gender and chromosomal diagnoses are not causal
factors of low birth weight
Tab. 6: Epidemiological data of the
subsample (32 Ss)
with the contemporary presence of
prematurity and low birth weight.
|
|
No. of Ss |
% |
|
|
(32 / 510) |
(6.27) |
|
|
32 |
100.00 |
|
M |
25 |
78.13 |
|
F |
7 |
21.87 |
|
M/F ratio |
357.14 |
|
|
Total sample:510 Ss |
|
|
|
M |
292 |
57.25 |
|
F |
218 |
42.57 |
|
M/F ratio |
133.04 |
|
|
Chi Square for gender = 4.576 with 1 df and p = 0.032 |
||
|
|
||
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
26 |
81.25 |
|
Mosaicisms |
0 |
00.00 |
|
Translocations |
4 |
12.50 |
|
Only clinical diagnosis |
2 |
6.25 |
|
Total sample:510 Ss |
|
|
|
Standard trisomy 21 |
461 |
90.39 |
|
Mosaicisms |
16 |
3.14 |
|
Translocations |
16 |
3.14 |
|
Only clin. Diagnosis |
17 |
3.33 |
|
Chi Square for chromosomal diagnoses = 9.145 with 3 df and p = 0.035 |
||
|
|
|
|
|
Prematurity + low birth weight |
Birth wieght in grams |
Gestational week at delivery |
|
|
<2000 |
From 32 to 36 |
|
|
>1999 and <2500 |
From 33 to 36 |
As we can see from the Tab. 6, the
contemporary presence of prematurity and low birth weight in 32 cases differs
from the whole series in a statistically significant way as for gender. So, it repeats
here the datum already seen in the prematurity subsample. There is also a
statistically significant difference as for the distribution of the chromosomal
diagnoses, but this result could be an artifact due to this small subsample.
Discussion.
Although prematurity and low birth weight in
Down are two events always reported, I did not find specific epidemiological
investigations in the literature. With the key words: Down syndrome,
prematurity (or low birth weight), epidemiology, I did search on Google, and on
Medline since 1960. I found a very recent paper on this topic (16). The rates I
reported here are smaller of those found by thease researchers, who rated 25%
prematurity births, and 14% low birth weights.
My investigation is surely carried out on a
very large sample, but the data were not collected at birth time, but later.
Perhaps this is a differentiating point. As for the results, first of all,
these two risk factors do not directly depend on the chromosome 21.
As I wrote above, when I started to be
concerned with Down syndrome Ss, I did not record these, and I could not
integrate them later. The first one I recorded was the gestational age at
delivery, because I was interested in previous stress symptoms. Then even the
low birth weight had its record. So it explains why there are more records
about prematurity than about low birth weight.
I reported prematurity and low birth weight,
as a part of my Down syndrome casuistry, as possible causal factors either for
cerebral palsy or squint (17-18). I get information that prematurity or low
birth weight or both were major risk factors for the onset of cerebral palsy
(19).
As for my whole series (510 Ss), the gender
distribution and M/F ratio, as well as chromosomal diagnoses distribution,
parallel the usual ranges (13-15).
Premature birth accounts for 13.34%. It is
surely a noticeable rate, but only two births out of fiveteen came in a
premature time. When compared to the whole sample (tab. 3) something new
appeared. Prematurity prevails among males in a statistical significant way. It
is not extraordinary information, because male prevalence usually runs in
mostly child neuro-psychiatry.
In its turn, low birth weight rated 10.98%,
lesser than premature births. No gender prevalence did get out of it, as
compared to the whole series.
The small subsample with the contemporary
presence of both risk factors showed a statistically significant increasing of
male prevalence, with a higher M/F ratio, as compared with the M/F ratio of the
prematurity subsample.
This seems to give another support to the
idea of increased male vulnerability even in Down people.
Conclusion.
Prematurity and low birth weight in Down
syndrome Ss are known events but not so frequent as told. In a series of 510
persons they occurred respectively in 13.34% as prematurity and in 10.98% as
low birth wight. Between them thirty-seven persons (6.27% of the whole series)
had both these risk factors. Prematurity showed a statistically significant
male prevalence when alone or with contemporary presence of low birth weight.
This fact seems a fully new finding.
References.
(1) Cocchi R.
(2) Cocchi R. Easiness to upper respiratory tract infections: An
investigation on 510 Down's syndrome persons. It. J. Intellect.
Impair. 1997, 10: 143-149
<www.stress-cocchi.net/Down5.htm>
(3) Cocchi R.
(4) Cocchi R. Favuto M. Hyperkinesis in
Down's syndrome: A survey on 510 persons It. J. Intellect. Impair. 1997,
10: 19-23. <www.stress-cocchi.net/Symptoms4.htm>
(5) Cocchi R. Favuto M. Time course of hyperkinesis in
Down's syndrome: A survey on 498 persons.. It. J.
lntellect. impair. 1998, 11: 141-146. <www.stress-cocchi.net/Symptoms7.htm>
(6) Cocchi R. Depression
in Downs: An epidemiological and clinical investigation on 510 subjects. 2002,
<www.stress-cocchi.net/Downs31.htm>
(7) Cocchi R. The difficulty of being combed as a curious symptom in
Downs. An epidemiological investigation on 510 subjects. 2003,
(8)
(9) Cocchi R. Evaluation of balance in Down persons. An epidemiological
and clinical investigation on 383 subjects. 2003,
(10) Cocchi R. Ligamentous laxity and hypotonicity in Downs. An
epidemiological investigation on 510 subjects. 2003,
(11) Cocchi R. Which relationship between tongue protrusion and joint
laxity / hypotonia in Downs? An epidemiological investigation on 452 subjects.
2004, <www.stress-cocchi.net/Downs43.htm>
(12) Cocchi R. Tongue protrusion in Downs. An epidemiological survey on
510 subjects. 2004, <www.stress-cocchi.net/Downs42.htm>
(13) Camera G., Mastroiacovo P.: Epidemiologia della sindrome di Down.
In. Ce.Pi.M. (ed): Aspetti epidemiologici, genetici, clinici, riabilitativi e
sociali della sindrome di Down. Ce.Pi.M., Genova 1984: 225-230.
(14) Hook, E. G Epidemiology of Down syndrome. In, Pueschel, S. M. and
Rynders, J. E. (eds.): Down Syndrome. Advances in Biomedicine and the
Behavioral Sciences. Cambridge: Ware Press,1983.
(15) Hook, E. B.; Cross, P. K. and Schreinemachers, D. M. (1983).
Chromosomal abnormality rates at amniocentesis and in live-born infants.
J.A.M.A. 249, 2034-2038,
(16) Frid C., Drott P., Otterblad Olausson P., Sundelin C., Anneren G.:
Maternal and neonatal factors and mortality in children with Down syndrome born
in 1973-1980 and 1995-1998. Acta Paediatr. 2004, 93:106-112.
(17) Cocchi R., Branchesi R.: Strabismo e disturbi pre-, peri-, e
neonatali in soggetti affetti da sindrome di Down. Indagine epidemiologica su
215 casi. Rass. Studi Psichiat. 1986, 75: 504-512.
(18) Cocchi R. Branchesi R. Non legame causale fra strabismo e paralisi
cerebrale infantili, da prematurita` e/o basso peso alla nascita, nei soggetti
Down? Riv. It. Disturbo Intellet. 1988, 1: 161-164. English text on <www.stress-cocchi.net/Downs25.htm>
(19) Susser M., Sergievsky G.H., Hauser W.A., Kiely G.L., Paneth N.,
Stein Z.: Quantitative estimates of prenatal and perinatal risk factors for
perinatal mortality, cerebral palsy, mental retardation and epilepsy. In:
Freeman G.M. (ed): Prenatal and perinatal factors associated with brain
disorders. NIHP, Washington D.C., 1985: 359-439.
Author's address. Dr Renato COCCHI, Via Rabbeno, 3.
42100 Reggio Emilia (Italy)
Email:
renatococchi@libero.it