Believe
me doc my dates were certain and I can recollect that date properly . Doctor,
you need not “Re-Date the Gestational Period” . How to proceed if report comes as a first time
that EFW is < 10 percentile.
A)
Group
A women: Well-dated Pregnancy: - Sonologically Pregnancy dating was done by 12
weeks of gestation. There is no doubt about stated gestational age. --> In
such cases the diag of FGR near term by USG is ,therefore almost certain. à No question of wrong dating—in such
an event there are four points have to
be answered for sono diagnosed FGR à 1) any structural anomaly? 2) Any two
soft markers for aneuploidy-was not categorically mentioned by referring
gynecologists. BY and large one should avoid CS because of presumable
(possible) structural / karyotypically abnormality . 3) to find out the
etiology in mother /cause-if there be any in mother for FGR . 4) Empirical
Tr.:- Rest, nutritious diet, Folic Acid, Proteins, Antioxidants, Vasodilators (sildenafil,
Arginine), Progesterone, 5) ACS (antenatal Cortio Steroids) 6) Monitor by clinical & serial USG
c-preferably Doppler 7) Deliver as
appropriate.
Group B:
Women where there is uncertainty
about dating either she fails to recollect the dates of LM/ No
clinical/USG in first trimester was contemplated as happens in refer cases: In the decades of eighties
and ninties when sonography was sparingly used then clinician riled heavily on
Shake test.
How to test for Lungs maturity? Under son guidance LA was aspirated from the
woman concerned where dating was uncertain and in amniotic fluid L:S ratio was
determined,:-If Pulmonary maturity the ration will
be >2: But in cases of
immaturity the L:S Ration will be < 2. An important prerequisite for the management of high risk
pregnancies is the accurate prediction of foetal lung maturity. A number of indices of foetal lung maturity
based on the determination of surfactant constituents in the amniotic fluid
have been proposed.
Amniotic fluid contains phospholipids, including phosphatidylcholine (lecithin),
sphingomyelin, phosphatidylinositol and phosphatidylglyerol (PG), some enzymes
of the pathways of phospholipid synthesis, lamellar bodies, and lung specific
apoproteins. The amount of these substances in amniotic fluid changes towards the
end of gestation in a manner related to foetal lung maturity. Determination of the lecithin to
sphingomyelin (L/S) ratio is by far the most widely used and accepted method.
However, there is still controversy regarding the high incidence of false
immature values, and the increased incidence of false mature values (from 1 to 15%) especially in
pregnancies complicated by diabetes mellitus; an immature L/S ratio may predict
respiratory distress syndrome (RDS) only in about 50% of cases. The
incidence of false immature L/S ratio as well as other amniotic fluid tests
depends upon patient variability, method employed, threshold taken for
differentiating a normal from an abnormal condition, and on the fact that only
few authors report their results in terms of sensitivity and specificity.
Where laboratory
facilities are minimal, it is advisable to perform the shake test or to measure
the optical density of amniotic fluid. However, when these tests indicate immaturity, additional tests, such as
determination of the L/S ratio or the lung profile (including PG), must be
performed. The utilization of these
tests is recommended for: 1) timing of delivery prior to elective caesarean
section; 2) management of complicated pregnancies; and 3) recognizing
indications for pharmacologic prevention of RDS in utero or at deliver. Respiratory
distress syndrome occurs in infants born with immature lungs.
The immature fetal
lung lacks an adequate supply of surfactant, a phospholipid-rich substance
which is produced in the type II cells of the alveolar epithelium. In the fetus, surfactant is secreted into the
potential air spaces of the lung and passes into the amniotic fluid as
gestation proceeds. It is now clear that most methods currently in use for
assessing fetal lung maturity depend on the detection of a sudden release of
surfactant into the amniotic fluid as the lung reaches a critical stage of
maturity. These methods, which include the lecithin/sphingomyelin ratio, the lung profile, total phospholipid or lecithin concentration,
fluorescence depolarization, lamellar body phospholipid concentration, and the
"shake" test,
are reviewed in the light of recent understanding of the nature of surfactant.
Possible sources of error in performing the
test in the laboratory, factors which could theoretically limit its ability to
reflect the state of fetal lung maturity and current information regarding its
reliability, in terms of clinical performance. Guidelines for future research
in this area are also suggested.
B)
Step
1-Measure Transcereballar Diameter&
Femur length . TCD if expressed in mm = exact gestational age in
weeks.
Indirect Markers of G.A.:- Some other biometric
measurements are little affected by growth restriction: Minimally affected is FL. taking that diameter as constant we can try to diagnose GA &
FGR in other way round:-
Therefore if FL is constant then we
can try to calculate the gest age at any stage of pregancy :
What
about AC Ratio as a diagnostic marker of
FGR ? Ans: Yes. It
may be one of the sono points favoring FGR but AC is dos not guide us abut of
estimation of GA as is Trans Cerebellar dia /or say FL . If such ratio is>
23.5% then it means that AC is lagging in length than AC: Indirect method of
assessing FGR.
Step
2. What is the
Ponderal Index? = FL/AC-
Foetal
Ponderal Index:-
EFW÷FL= Ponderal Index of Foetus. If Foetal P Index is falls below 10th
centile then diag of FGR is almost certain,. But clinicians like sonologists
are happy with “gestation specific foetal wt chart “.
Ponderal Index after birth: Birth Weight ÷Crown Rump Length.
This will be low in cases of FGR. In the process of IUGR at first there is
restriction imposed on weight and later foetal length is restricted.
Step 3. Re-Date the Gestational Period:-
a)
The biometric measurement tally with the stated LMP- Proceed with anomaly
screening again/Soft marker for chromosomal markers which might have been
missed earlier or has appeared for first time, No obvious maternal or foetal
factor as an etilogy of FGR and moreover FGR is mild in nature then foetal
surveillance will be DFMC(Daily Foeatal Kick Chart as perceived by mother)
backed up by Repeated Umbilical.
A Doppler:- NST 2 weekly, AFI weekly,
Watch growth Trend for 3 weeks if no pressing indication for
deliver after 37 weeks.
But Foetal compromise as evidenced by
serial changes on the following
parameters but not all parameters reflect exactly . Therefore people rely more
on reproducible indices like Doppler of fetoplacental vessels. The parameters
are therefore as follows with an idea in
the back of mind to deliver after
completion of à Deliver after 34 weeks’ s far as possible along with NICU
facilities..The parmeters on which
clinicians bank most are i) BPP daily,
ii) Abnormality in MCA Doppler weekly or iii) DV Doppler every 4th
day -> if deterioration then deliver before 34 weeks after ACS.
?
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