Can beta hcg at 16-21 weeks be used as one of the prenatal laboratory to predict preeclampsia?

Can beta hcg at 16-21 weeks be used as one of the prenatal laboratory to predict

preeclampsia?

 

Human chronic gonadotropin (hcg) refers to the glycoprotein hormone that results

during pregnancy and made by the developing embryo following conception.[1]

Beta hcg or the pregnancy hormone is produced by the implanting egg’s cells and can

 also occur without an embryo. It can be detected 8 to 9 days after ovulation in maternal

plasma or urine and reaches its peak at about 8 to 10 weeks and then declines in the

course of the pregnancy.[2]

 

Preeclampsia refers to the incidence of hypertension in pregnancy linked with significant

amounts of protein in the urine and entails damage to the maternal endothelium,

kidneys and liver. It may progress from 20 weeks gestation and differs among patients,

with most cases being diagnosed as pre-term. Preeclampsia has no known cure

excepting Caesarean section or induction of labor.[3]

 

According to one study, women prone to hypertension development during pregnancy

may be identified by a second-trimester test for elevated levels of beta-human chronic

gonadotropin (beta-hcg), which however, may lack the accuracy in identifying women at

 risk for preeclampsia. Based on a study of preeclampsia in 6,286 nondiabetic women,

 those who had more than one child and had elevated beta-hcg levels had a greater risk

 of developing hypertension and preeclampsia.[4]

 

According to a second study, second-trimester elevated maternal urine beta-core

 fragment of hcg predicted small for gestational age (SGA) infants, and was better in

 prediction than other serum analytes. The beta-core fragment that accumulates in

 maternal urine is the terminal metabolite of hcg. There was previous evidence that

 beta-core fragment of hcg may be used as trophoblastic function marker, with second-

trimester urine beta-core fragment having been elevated in clinically normal women who

 became preeclamptic in due time.[5]

 

Spot urine specimens from women in the gestational age range of 14-24 weeks were

obtained and refrigerated. To determine whether there was significant connection

between beta-core fragment levels and later SGA birth, the Mantel-Haenszel test of

linear association was used. There was a plotting of receiver operating characteristics

(ROC) sensitivity curve against false-positive rate for SGA prediction at various beta-

core fragment threshold values.[6]

 

The etiology of fetal growth restriction (FGR) is heterogeneous, with many factors being

considered, and preeclampsia is an accepted FGR risk factor. Women may be

predisposed to preeclampsia if there is failure of the second wave of endovascular

trophoblastic invasion. Based on the findings, early disturbance of trophoblast

dysfunction occurs in a notable percentage of women who deliver SGA offspring. The

intial effect of a hypersecretory state development might be the cause of heightened

levels of placental function markers found in preeclamptic women, like hcg, inhibin-A

and activin-A. As FGR predictor, beta-core fragment may be better than its parent

molecule.[7]

 

According to a third study, there is strong correlation between elevated maternal

inhibin A concentration with a later risk of preeclampsia. Further investigation is in

order on the potential use of second trimester inhibin A measurement in a preeclampsia

screening strategy.[8]

 

[1] “Human chronic gonadotropin”, Wikipedia, 27 April 2011,

<http://en.wikipedia.org/wiki/Human_chorionic_gonadotropin>  [accessed 30 April 2011]

[2] “What is beta hcg?”, OBfocus, 2009, <http://www.obfocus.com/questions/qanda7.htm>

[accessed 30 April 2011]

[3] “Pre-eclampsia”, Wikipedia, 2 April 2011, <http://en.wikipedia.org/wiki/Pre-eclampsia>

[accessed 30 April 2011]

[4] Ellice S. Lieberman et al, “The value of elevated second-trimester beta-human chronic gonadotropin in

predicting development of preeclampsia”, Abstracts Health, 1997,

<http://www.faqs.org/abstracts/Health/The-value-of-elevated-second-trimester-beta-human-chorionic-gonadotropin-in-predicting-development-o.html>  [accessed 30 April 2011]

[5] Ray Bahado-Singh, MD et al, “Maternal Urine [beta]-core hcg Fragment Level and Small for Gestational

Age Neonates”, Obstetrics & Gynecology, May 2000,

<http://journals.lww.com/greenjournal/Fulltext/2000/05000/Maternal_Urine__beta__core_hCG_Fragment_Level_> [accessed 30 April 2011]

[6] ibid

[7] ibid

[8] J. Aquilina et al, “Second-Trimester Maternal Serum Inhibin A Concentration as an Early Marker for

Preeclampsia”, PubMed.gov, July 1999, <http://www.ncbi.nlm.nih.gov/pubmed/10411808>

[accessed 30 April 2011]

 

Credit:ivythesis.typepad.com