FGR: What we need to know normal Indian fetal growth chart, definition, diagnosis of FGR, etiology, , kinds of FGR, and role of Doppler USG (Doppler studies in particular) in the prediction /diagnosis and timely intervention of FGR thereby averting foetal death .

How to define  FGR : What is country, ethnicity and racial gestational based –EFW (expected Foetal weight) ? Ans:-How many of your sonologist friends supply growth chart along with sonography report pages?? We know and aware that for every country   population standards is available as normal growth chart for normal growing foetus in utero and plotted against the gest age. Local normal growth chart are installed in the machine like PI,RI ,PSV of Doppler. Intra uterine growth retardation (IUGR-now abbreviation is FGR)    is defined    when the intrauterine   weight of the foetus falls below the    tenth percentile for gest age (  ie. duration  of pregnancy ) . However the cut off value of diagnosis IUGR is 10^th percentile weight for foetal age. Against the standard week wt curve  

The other definition of FGR?? The other   index of expressing IUGR is when the estimated foetal weight  falls below  the two standard derivation below the mean

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In practice we come across :: Optimum  Condition 1: Dating USG was done and CRL matches with stated LMP:---> Thus the precondition   of diagnosis of FGR demands   accurate pregnancy   dating (preferably on USG done at 6-10 weeks of gestation)  . Dating USG must be done   so that the present estimated foetal ut can be compared   with    the reference chart and diagnosis or exclusion of FGR can be     made. Now for every country   population standards are available.  i e   foetal weight for each  gestational   age has been   calculated and available to sonographer  . So before the diagnosis of IUGR(FGR)   is made LMP  must be  known   with certainly  otherwise  false  diagnosis  of IUGR will be made.

In practice we come across ::Suboptimum Condition 2:--If  LMP is not certain or  unreliable -> then  at least  one obstetric USG  carried out  at 16-18 week of gestation can also  be  used as a reference    value  about the duration of preg  ( I e preg dating )

 In practice we come across :: Preg woman coming to hospital at 28 weeks : Suboptimum Condition 3:-No sonography was done and a preg woman come to hospital for booking only based on the fact that her admission to hospital will be refused if she does not attend at least 2-3 times in ANC period. This information may  come from  by  the neighbors  or lady Health visitors or ASHA workers . By  the time she comes for  first time it may be as late as 28-32 weeks, At that time she is usually  offered a date for USG on which she may or may not turn up. However if USG is done at early third trimester dating can be still be done from Trans cerebellar diameter or femur length. But trans cerebellar dia is sadly  ever mentioned by our sonologist.-

 Assignment of foetus as per FEW :-Weight wise   classification of Foetus while in utero:-

Average weight Foetus:--- - appropriate for  gest age   ( Babies born with birth weight   between the 10 th  and 90^th   percentile for gest age

A)                    Large - Large for gest age  - Babies   with birth weight  about the 90^th  percentile

SAG foetus:- – small for gest age ( < 10^th percentile )

How to prepare the chart for local population which will be representative? How to frame a chart??  How to local population based normal / standard fetal weight   as per gestational week?

To calculate   this ( country wise ) 100/500 women with  known  LMP   - estimation   of foetal  wt is done at different  gestational age is done. Then   these foetal   weights are plotted against the gest  weeks. These    women must not   have any  disease   and birth wt after delay   should be   normal . Thus these pregnancies are essentially  normal   in all respects . This is   also called   population standard or “ growth   curve “ or “ Reference Range “ . Thus if a foetus  exhibits 5^th percentile for wt  in a particular  gest age ( say 34 weeks )    it means   only 5%  of healthy women of that locality with normal  birth wt  ( proved  later ) will have   such foetal  weight.

Which  term is better ?

IUGR   - Intra uterine   growth  

SFD-  Small for date

Growth   restricted foetus

SGA – small   for gestational  age   . The term retorted  foetus .

Why we have changed the 4 decade long terminology of IUGR ? We have moved to FGR-but why?? The very term FGR means some hurtful or rudeness, offences, unacceptable or unsatisfying to the couple and family members as they consider failure to gain weight is equated to irreversible  brain changes of fetus and foots won’t be able to catch up later even if born by CS  which is far from truth !! But we know such happening is  not true, and fortunately timely intervention will hopefully improve foeatal weight and seldom there will be residual damage (delayed mile stones). Why we have changed to growth Retardation to restriction?? Many   women and   their family members think that retardation   of foetus what have occurred in    utero is irreversible   . So  women  &  family  members  got  scared   of the term Retardation .As such    the present  nomenclature of this entity   is FGR i.e.”Growth   restricted foetus”  . This means    growth is temporally restricted which is correctable by proper treatment and it is not a permanent / irreversible damage.

Caution: How sensitive is sonological measurements in diagnosing FGR?? As many as 10-15 % of normal fetuses will exhibit abnormal   USG   parameter!!! Reasoning:-

FGR  can manifest  as less maternal weight gain,  a decrease in uterine height,(SFH) , Abd circumference of mother –girth in cm do not increase as per , clinically on palpation Liquor may be less , with toned uterus(less relaxed) . So far as foetus is concerned  , USG may reveal its  less subcut  tissues  and muscle mass ( singly  or   in various   combination ) and usually AC as per gest age will be less . Ideally all these sonographic metrics should be mentioned  by the sonologist such   measurements should be done   to diagnose FGR. But in practice   all the diameters / circumferences   are not measured .Even  if all the parameters   are used , mentioned and used in calculating EFW  àthen too  there can be   missing of some IUGR    babies . By   contrast if all the measurements are   used then there is a possibility that 10-15 % of normal fetuses will exhibit abnormal   USG   parameter .

How  obstetricians used to  diagnose IUGR / SFD  in the decal  of fifties / sixties when us was not  widely available in India ?

The    then  clinicians used to  assess foetal  weight by the  followings but unfortunately     in many  cases the presumption of diagnosis   of IUGR was  wrong   even by the most   experienced clinicians.