Changes in hemoglobin F levels in pregnant women unaffected by clinical fetomaternal hemorrhage.ppt

8/10/2019 Changes in hemoglobin F levels in pregnant women unaffected by clinical fetomaternal hemorrhage.ppt

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Changes in hemoglobin F levelsin pregnant women unaffected

by clinical fetomaternal

hemorrhage


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Introduction

Hemoglobin F (Hb F) is predominantly produced in fetal

life

F cells are measured as the proportion of total red cells

using the KleihauerBetke acid elution method or flow

cytometry

Hb F is measured as a proportion of the total Hb in red

cell lysates by high-performance liquid chromatography

(HPLC)


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Introduction

Complete automation of the HPLC method has made this

procedure available to many clinical laboratories

As a high Hb F level interferes with Hb A1cmeasurements in

some commercially available assay systems [7], Hb F levels

may also be affected by Hb A1c

The physiological changes in %Hb F during pregnancy as

determined by HPLC have not been studied extensively


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Material and methods

All 357 pregnant participants gave birth

between January 2011 and July 2012 at our

institution and were free from clinical

fetomaternal hemorrhage (FMH)

12 (3.4%) were known to be complicated with

diabetes mellitus and 48 (13.4%) were

diagnosed with gestational diabetes mellitus in

the current pregnancy

Total of 490 blood samples from the 357

women were used for simultaneous

determinations of both %Hb F and %Hb A1c


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Material and methods

490 blood

samples from

357 women

Before pregnant (n=21)

1st

trimesters (n=150)

2ndtrimesters (n=116)

3rdtrimesters (n=192)

postpartum (n=11)


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Results

mean %Hb F level during the 1st

trimester did not differ significantly

fromthat determined before pregnancy

Longitudinal

study of 21

women

%Hb F level declined significantly during

pregnancy in the absence of a

significant change in Hb A1c level

Cross-

sectional

study

%Hb F level tended to increase after

delivery (P=0.0667)

Longitudinal

study of 11

women


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Fig. 1. Changes in the %Hb F levels before, during, and

after pregnancy


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Results

the majority of women exhibited a decrease in

%Hb F level and none exhibited an increase in

%Hb F bymore than 0.1%

Women with a higher %Hb F level during the 1st

trimester were significantly more likely to

exhibit a larger decrease in %Hb F during

pregnancy

%Hb F levels : 0.1% to 2.9% with a median valueof 0.7% during the 1sttrimester

%Hb F levels : 0.1% to 2.8% with a median of

0.5% during the 3rdtrimester

An

analysis

of 49

women


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Fig. 2. Longitudinal changes in %Hb F levels

during pregnancy in 49 women


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Fig. 3. Correlation between %Hb F levels during the 1sttrimester and net decreases in %Hb F levels during

pregnancy


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Fig. 4. Distribution of %Hb F levels determined during

the 1st and 3rd trimesters


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Results

A weak but statistically significant negative

correlation between %Hb F and %Hb A1c

levels was observed

Mean %Hb F levels did not differ significantlybetween 475 samples with %Hb A1c level


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Fig. 5. Association between levels of %Hb F and %Hb

A1c in 490 blood samples from 357 women


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Discussion

%Hb F level was highest during the 1st

trimester of pregnancy and declined gradually

toward the 3rd trimester

%Hb F level was significantly increased during

the 1sttrimester compared with those during

the 2nd and 3rd trimesters

The increase in red cells containing Hb F during

the earlier stages of pregnancy has been

suggested to be due to an increased number of

adult F cells


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Discussion

Fetal red cells during the 1st trimester exclusively contain

Hb F, while adult F cells contain both Hb F and Hb AHb

F ranging up to 25% of the total Hb in adult F cells

Hb F accounts for an approximately 10% of the total Hb

in adult F cells

Physiological FMHmay have contributed partly to the

elevation of the 1st trimester Hb F levels


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Discussion

Effect of parity on the Hb F level was not seen in

this study

A significant increase in %Hb F level during the 1st

trimester compared with that before pregnancy

was not confirmed in this study

Although the reason why %Hb F decreases in the

later stages of pregnancy remains to be

determined, it may be due to deceleration of

erythropoiesis during the latter half of pregnancy


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Conclusion

The data presented in this work may be

used as reference intervals of %Hb F

determined with HPLC during

pregnancy


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Thank You

Changes in hemoglobin F levels in pregnant women unaffected by clinical fetomaternal hemorrhage.ppt

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