Briend, André

Horizon / Pleins textes

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DO MATERNAL NUTRITIONAL RESERVES LIMIT 
FETAL GROWTH I N  UNDERNOURISHED WOMEN 2 
By : Andre BRIEND 
ORSTOM - O.R.A.N.A. 
BP. 1386 - Dakar 
Senegal 
. -  
RESERTES LIMIT FETAL G R O k ?  
? An&é BRIEND, .OFSTOM, Nutrition I . 
BP. 1286, Dakar, Séné@, Kest Africa 
Résumé de la  présentation Orzle au Congrès de San Diego - 
Nutrition - Août 1981 . 
Epidemiological evidence shows that  i n  undernourished pregnmt 
women the f e t a l  growth is  l e s s  affected than the accumulation o f  maternal 
nutr i t ional  reserves. On the  other hand, low rnaternal nutr i t ional  reserves 
ase said t o  be a na jor  l imiting factor of f e t a l  G a r t h  in the developing 
world. If these two propositions were true,  one would expect the  b i r t h  
w e i g h t  t o  be roughly proportional t o  maternal weight i n  th in  undernowishecl 
women. This assertion w a s  tes ted in 136 Senegalese women selected in a 
post nata l  check-up f o r  t he i r  poor m t r i t i o n a l  status. A log-log regressior. 
shoved that  : 
log ( b i r t h  weight) = - 0.084 - + 0.322 - + 0.240 * l o g  (maternal weigh:) 
The slope. of  th i s  regression is significantly l a - e r  than 1 ( ’p less t h  
0.001). In other words, the  mothers that  weighed l e s s  had noticeably bigger 
newborns when conpared t o  maternal weight. This r e j ec t s  a t  l ea s t  oneof 
the  tes ted propositions. In this part of Africa,aost mothers successfully 
breast-feed t h e i r  babies a f t e r  delivery we suggest that  the limiting ef fec t  
of natemal  nut r i t iona l  reserves on f e t a l  growth should be reconsidered 
in the first place. 
B i r t h w e i g h t  is a m a i o r  d e t e r m i n a n t  of s u r v i v a l  d u r i n g  t h e  f i r s t  
mon ths  OF I i f e .  I n  t h e  d e v e l  o p p i  ng c o u n t  i r e s ,  m e a n  b i r t h  we¡  g h t  of t e r  m 
babies  i s  lower  t h a n  i n  t h e  i n d u s t r i a l i z e d  c o u n t i e s .  T h i s  r e s u l t s  i n a n  
e x c e s s  sf n e o - n a t a l  
i m p r o v e d  s t a n d a r d  of p e d i a t r i c  G a r e ,  B e t t e r  s t a n d a r d s  of c a r e  is t h e  
p r i o r i t y  t o  d e c r e a s e  n e o - n a t a l  m o r t a l i t y  i n  t h e  t r o p i c s ,  bu t  a b e t t e r  
knowledge  a b o u t  t h e  f a c t o r s  d e p r e s s i n g  b i r t h  w e i g h t s  is d e s i r a b l e .  
m o r t a l i t y  w h i c h  c o u l d  n o t  be t o t a l l y  r e m o v e d  by a n  
S m a l l  f o r  d a t a  newborns h a v e  a n a t o m i c  c h a r a c t e r i s t i c s  r e m i n e s c e n t  
of t h o s e  of o l d e r  c h i l d r e n s u f f e r i n g  f r o m  m a l n u t r i t i o n .  
Since on the o t h e r  h a n d ,  women  in  t h e  poor c o u n t r i e s  h a v e  
o f t e n  w e l l  b e l o w  t h e  r ecommanded  a l l o w a n c e s ;  i t  i s  o f t e n  t a k e n  f o r  g t a n -  
ted  tha t  m a t e r n a l  m a l n u t r i t i o n  i s  t h e  m a i o r  c a u s e  of f e t a l  g r o w t h  
r e t a r d a t i o n .  It i s  o f t e n  s t a t e d  t h a t  m o t h e r s  have n o t  e n o u g h  of n u t r i e n r s  
t o  s u p p o r t  fetor g r o w t h  u p t o  t h e  e n d  of p r e g n a n c y  of t h a t  f e t a l  g r o w t h  
i s  r e g u l a t e d  by mate r  na1 n u t r  i t  i o n a l  r e s e r v e s  : i t  has  e v e n  b e e n  s ugges  - 
t e d ,  from a t e l e o g i c a l  p o i n t  of v i e w  t h a t  i f  a m o d e r a t e l y  m a l n o u r i s h e d  
m o t h e r  must care f o r  a runt ,  c h a n c e s  a r e  t h a t  t h e  m o t h e r  w i l  I r e c o v e r  
w h e n f o o d  becomes  a v a i l a b t e  a n d  t h a t  l o w  b i r t h  w e i g h t  s h o u l d  be c o n s i -  
d e r e d  as a n  a d a p t a t i  on t o  t o w  f o o d  i n t a k e s  . 
T h e s e h y p o t h e s i s  a s s u m i n g  a l i m i t a t i o n  or r a t h e r  a r e g u l a t i o n  of b i r t h  
w e i g h t  by m a t e r n a l  n u t r i t i o n a l  r e s e r v e s  i m p l y  t h a t  w h e n  t h e  m o t h e r s  
c r e  s e r i o u s l y m l n o u r i s h e d ,  o n e  s h o u l d  h w e  a c o n s t a n t  r a t i o n  b e t w e e n  
m a t e r n a l  a n d  n e o - n a t a l  w e i g h t .  T h i s  s h o u l d  b e  t h e  c a s e  i n  p o p u l a t i o n  
w h e r e  b i r t h  w e i g h t  i s  d e f i n i t e l y  below t h e  o p t i m a l  
c i a t d  w i t h  t h e  l o w e s t  n e o - n a t a l  m o r t a l i t y .  M o v i n g  from t h e  m o s t  
u n d e r w e i g h t  w o m e n  t o w a r d  t h o s e  w i t h  a n  a c c e p t a b l e  body  w e i g h t ,  o n e  
f o o d  i n t a k e s  
b i r t h  w e i g h t ,  a s s o -  
s h o u l d  o b s e r v e  a p r o g r e s s i v e  i n c r e a s e  of bi r t h we¡  g h t  , pr o p o r  t i  o n a l  t o  
b i r t h  weï ght, if o n e  admi t s t  hat t h e  f e t  us h a s  some  pr i or¡ t y  o v e r  t h e  
. build-up of m a t e r n a i  n u t r i t i o n a l  r e s e r v e s ,  A b i r t h  w e i g h t  i n c r e a s i n g  
m o r e s l o w l y  t h a n  the m a t e r n a l  w e i g h t  i s  c o n c e i v a b l e  o n l y  w h e n  t h e  b i r t h  
ight is a p p r o a c h i n g  i t s  o p t i m a l  v a l u e .  
. . ./-. .
To t e s t  the h y p o t h e s i s  of a b i r t h  w e i g h t  r e g u l a t i o n  by m a t e r n a l  w e i g h t ,  
w e  exami  ned t h e  r e k a t  ion  b e t w e e n  t h e s e  t w o  v a r  i a b l e s  i n a s a m p l e  of S e n e g a l  ese 
women  s e l e c t e d  fo r  t h e i r  poor  nutr  i t i 'onal  stat us a n d  whose  n e w b o r n s  h a d  
a b i r t h  w e i g h t  we1  li be l  ow t h e  opt ¡  m a l  
i n  t h i s  s a m p l e  t h e r e  w a s  a c o n s t a n t  r a t i o  b e t w e e n  m a t e r n a 1  a n d  n e o - n a t a l  
we¡ ght  . 
I .. 
b i r t h  we¡  g h t  . W e  d e t e r  mined  w h e t h e r  
S u b i e c t s  a n d  m e t h o d s  : 
This s t u d y  w a s  d o n e  i n  a m a t e r  n i t  y hos pi t a l  i n  t h e  per¡  p h e r y  of 
D a k a r  a t t  e n t e d  by the m o s t  under  pr ; v i  I e g e d  w o m e n .  of t h e m ,  ' bef or e 
g o i n g  back h o m e  have  a s h o r t  C I  i n i c a l  e x a m i n a t i o n  w i t h  a c o n t r o l  of b l o o d  
p r e s s u r e  u n d  r e s a r c h  of s e v e r e  a n e m i a s  . D u r i n g  t h i s  c h e c k - u p ,  w e  t a k e  
a n t  h r o p o m e t r  i c  d a t a  of t h e s e  w o m e n  i n order  t o  m a k e  a I o n g  t e r m  s u r v e y  o n  
b i r t h  w e i g h t  t e g u l a t  i o n .  For  t h i s  p r e l i m i n a r y  w o r k ,  w e  s e l e c t e d ,  a m o n g  t h e  
450 r e c o r d s  of t w o  m o n t h s  of t h e  s u r v e y ,  136 w o m e n  w h o  h a d  a mid u p p e r  
a r m  c i r c u m f e r e n c e  b e l o w  80 % of t h e  i n t e r n a t i o n a l  s t a n d a r d s ,  i . e .  b e l o w  
228 mm. We chosed t h i s  c r i t e r i a  b e c a u s e ,  c o n t r a r i l y  t o  n u t r i t i o n a l  
b a s e d  on  body w e i g h t ,  i t  i s  n o t  i n f l u e n c e d  b y  t h e  s i z e  of  t h e  u t e r u s  or 
b y  t h e  w a t e r  r e t e n t  i o n  w h i c h  w a r y  a l o t  b e t w e e n  d i f f e r e n t  w o m e n  a n d  a r e  
no t  r e a l l y r e l a f e d  t o  m a t e r n a l  n u t r i t i o n a l  s t a t u s .  These w o m e n  had a m e a n  
w e i g h t  of 48.9 kg ( r a n g e  : 37.5 - 63) .  T h e i r  m e a n  h e i g h t  w a s  I .63 m - 
( r a n g e  : 147 - 179 c m ) .  M e a n  b i r t h  w e i g h t  i n  t h i s  s a m p l e  w a s  2q890kg.  
T h i s  i s  w e l l  b e l o w  t h e  o p t i m a l  b i r t h  w e i g h t  a s s o c i a t e d  w i t h  t h e  l o w e s t  
p e r i n a t a l  m o r t a l i t y  w h i c h  i n  W e s t  A f r i c a ,  as i n  Europe  or i n  N o r t h  
A m e r i c a  i s  b e t w e e n  3.5 a n d  4.0 k g .  ' 
Mos t 
i n d i c a t o r  
B i r t h  w e i g h t  u n d  m a t e r n a l  w e i g h t  w e r e  t r a n s f o r m e d  i n t o  l o g a r i t h m s  
ba . fo re  t h e  s ta t is t ical  a n a l y s i s .  I f  b i r t h  w e i g h t  w e r e  a c o n s t a n t  f r a c t i o n  
of m a t e r n a l  w e i g h t ,  o n e  s h o u l d  observe a s i g n i f  í c a n t  c o r r e l a t i o n  b e t w e e n  
. these t w o  v a r i a b l e s  w i t h  t h s  s l o p e  of the  r e g r e s s i o n  l i n e ,  or t h e  a l l o m e -  
t r i c  c o e f f i c i e n t  c lose t o  I .  
The I ogar i thms of b i r t h  Wei ght an¿ of m a t e r  na1 we igh t  are s i  g n i f i c u n -  
t l y  c o r r e l a t e d  ( r = 0.226, p less than 0.05). 
The s lope 
c a n t l y  less than I ( p I ess than 0.01). 
I n  a the r  words ,  these i s  n o c o n s t a n t  r a t i o  b e t w e e n  m a t e r n a l  and neo-na ta l  
w e i g h t s  and b i r t h  w e i g h t ,  r e l a t e d  to m a t e r n a l  w e i g h t  is s i g n i f i c a n t l y  
h ighe r  in women w i t h  Q smal I body s ize .  
of t h e  r e g r e s s i o n  l i n e  i s  0.322, s .  d. 0120. T h i s  i s  high¡y signi-  
i 
. 
! 
J 
D i s c u s s i o n  : 
Al t . .ough t h e  c o r  r e l  a t  
I 
on coef 
. .  
, .  
i c i e n t  b e t w e e n  t h e  loga r  t h m s  o 
mr ; l t e rna l  a n d  n e o - n a t a l  w e i g h t s  i s  s i g n i f i c a n t  ( p l e s s  t h a n  0,05),, 
v a r i a t i o n s  of m a t e r n a l  w e i g h t  e x p l a i n  5.1 % o n l y  of t h e  v a r i a n c e  of 
b i r t h  w e i g h t .  T h i s  f i t s  p o o r l y  i n t h i s  p o p u l a t i o n  of p o o r l y  n o u r i s h e d  
women w i t h  t h e  c o n c e p t  of m a t e r n a l  r e s e r v e s  b e i n g  a m a i o r  I i m i t i n g  or 
r e g u i a t i n g  f a c t o r  of f e t a l  g r o w t h .  
T h a t  m a t e r n a l  a n d  n e o - n a t a l  w e i g h t  a r e  no t  r e l a t e d  by a c o n s t a n  
r a t i o  i s  a l s o  d i f f i c u l t  t o  e x p l a i n  assuming t h a t  b i r t h  w e i g h t  is r e g u l a t e d  
by m a t e r n a l  w e i g h t .  T h e  h y p o t h e s i s  of l o w  b i r t h  w e i g h t s b e i n g  a n  a d a p t a -  
t i o n  t o  I ow 
t i o n  of b i r t h  w e i g h t  i n  u n d e r w e i g h t  women  i s  l e s s  t h a n  e x p e c t e d  i f  t h i s  
r e d u c t i o n  w e r e  to a d j u s t  n e o - n a t a l  s i z e  t o  m a t e r n a l  n u t r i t i o n a l  r e s e r v e s .  
m a t e r n a l  r a e r v e s  d o e s  no t  s e e m  I i kel y : t h e  obse rved  r e d u c -  
E n e r g y  n e e d s  of br e a s t  f e d  i n f a n t  s a r e  rough1 y pr o p o r  t i  o n a l  t o  the ;  r 
body  w e i g h t .  M a t e r n a l  e n e r g y  r e s e r v e s  a r e  a l s o  d i r e c t l y  r e l a t e d  to t h e i r  
w e i g h t . . O n e  s h o u l d '  o b s e r v e  a c o n s t a n t  r a t i o  b e t w e e n  t h e s e  t w o  v a r  i a b l e s ,  
W e  sugges t  that  m a t e r n a l  n u t r i t i o n a l  r e s e r v e s  d o  n o t  r e g u l a t e  nor  
l i m i t  f e t a l  g r o w t h .  T h i s  i s  s u p p o r t e d  by t h e  v e r y  s a t i s f a c t o r y  g r o w t h  
of b r e a s t  fed  i n fan ts  i n S é n é g a l  . 
Low b i r t h  w e i g h t  n e w b o r n s  of t e n  c a t c h - u p  i n t e r n a t i o n a l  s t a n d a r d s  w h i  le 
they  a r e  breas t  - fed  on1 y a l  though  the¡ r nu t r i  t i  o n a l  n e e d s  a r e  mor e 
d e m a n d i n g  for  the mot h e r  t h a n  t h e y  w e r e  in , u t e r o ' .  
A n  a l t e rna t  i v e  in t e rp re t a t i  on cou1 d be that  t he  e f f ec t  of m a t e r  naIl we igh t  
on b i r th  Wei ght  m i  ght  be .media ted  by a 
pec ies reguta t ion  of b i r t h * w e i g h t  b y  maternal c a r d i a c  o u t  put recemttty" 
been suggested by B a t t a g l i a  e t  a l .  
b e t w e e n  m a t e r  na1 and  neo-na ta l  w e i g h t .  T h e  observed a l  l ome t r i c  e x p o - .  
nent in our s a m p l e ,  w h i c h  i s  marked ly  less than  one suggests that a s i m i l a r  
r e g u l a t i o n  c o u l d  e x i s t  i n  human reproduct ion.  
vascul  a r  mechanis  m .  An i nt ers- 
- .  
c o n s i d e r i n g  the a l l o m e t r a i c  r e l a t i o n  
1 t seems ve ry  l i k e l y  t h a t  unde rwe igh t  women have a reduced  c a r d i a c  
o u t p u t  compared t o  heav ie r  women. T h e  r e l a t i o n  be tween body w e i g h t  and  
c a r d i a c  output however  i s  u n l i k e l y  to be l i n e a r .  
C a r d i a c  output  i s  more  l i k e l y  to be r e l a t e d  to the power 2/3 of ma te rna l  
we¡ ghf. 
If f e t a l  growth i s  l i m i t e d  when  f e t a l  oxygen  uptake  r equ i r e s  a g i v e n  
p ropor t ion  of m a t e r n a l  c a r d i a c  output ,  one  would e x p e c t  a n  a l  I ome t r í c  
exponent  c lose  to 0 .66 be tween ma te rna l  a n d  neo-na ta l  w e i g h t  or e v e n  
a l o w e r  one if f e t a l  oxygen  uptake  uncrease more r a p i d l y  than f e t a l  w e i g h t  
as suggested by M. H o I l  yday.  T h i s  
our data. . 
last  possi b i  I i t y  i s  compat i  bl e w i t h  
Materna l -neo-na ta l  r e l a t i  o n  r e c e i v e d  1 i t t l e  a t t e n t i  on i n t h e  s tudy  
of human birth w e i g h t ,  T h i s  a p p r o a c h  however ,  may g ive  some cf ves on 
b i r t h  w e i g h t  r e g u l a t i o n ,  I t  suggests t ha t  m a t e r n a l  n u t r i t i o n a l  reserves 
are u n l i k e l y  to d i r e c t l y  
chanism c o u l d  be i n v o l v e d .  
r e g u l a t e  b i r t h  w e i g h t  and  tha t  a vascular  m e -  


Do maternal nutritional reserves limit fetal growth in undernourished women ?

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