Table 1.

The summary of data concerning apelin concentration and apelin mRNA expression levels in GDM patients as compared to control patients.

Characteristics of the Study Group	Measured Data Type	Parameter Level as Compared to Control	References
Analysis of 20 studies concerning apelin serum concentration levels in 1493 GDM and 1488 control patients	protein concentration	not altered	[167]
Apelin peripheral blood concentration levels in 79 GDM and 80 control patients in the second trimester, as well as in 87 GDM and 88 control patients in the third trimester	protein concentration	increased	[212]
Apelin maternal serum concentration levels in 30 GDM and 30 control patients	protein concentration	increased	[213]
Apelin cord blood concentration levels in 30 GDM and 30 control patients	protein concentration	not altered	[213]
Apelin plasma concentration levels in 101 GDM and 101 control patients between 24 and 32 weeks of gestation, as well as in 20 GDM and 16 control patients at term	protein concentration	not altered	[214]
Apelin mRNA expression levels in SAT, VAT, and placental tissue in 20 GDM and 16 control patients at term	mRNA expression	not altered	[214]
Apelin maternal blood concentration levels in 24 GDM and 21 control patients	protein concentration	not altered	[215]
Apelin cord blood concentration levels in 24 GDM and 21 control patients	protein concentration	decreased	[215]
Apelin serum concentration levels in 127 GDM and 109 control patients (during pregnancy), as well as 30 GDM and 20 control patients (post-partum)	protein concentration	decreased	[217]
Apelin serum concentration levels in 10 GDM and 10 control patients	protein concentration	decreased	[218]
Apelin breast milk concentration levels in 10 GDM and 10 control patients	protein concentration	decreased	[218]

Abbreviations: GDM—gestational diabetes mellitus; SAT—subcutaneous adipose tissue; VAT—visceral adipose tissue.