Cell-type Changes References
Th1 No significant change during reproductive cycle [33]
Th2 Diminished during mid-luteal phase as compared to early follicular phase [33]
Th1/Th2 ratio No significant change during reproductive cycle [33]
Th17 Lower number in pregnancy state compared to non-pregnancy state [123]
No difference in circulating Th17 cells between all trimesters and non-pregnancy state [124]
No difference in circulating Th17 cells between certain pregnancy period and non-pregnancy period [105, 125]
Higher in decidua as compared to blood during first trimester [124]
Tregs Density gradually increases during proliferative phase in peripheral blood and endometrium [126]
Increase progressively in peripheral blood during first and second trimester while as decrease during third trimester as well as post-partum [5,127]
Suppressive action increased during first and second trimester while as weakened during third trimester compared to non-pregnant women [128]
Elevated in peripheral blood during late follicular phase compared to luteal phase [52]
Th17/Treg Ratio
Lower in pregnancy as compared to non-pregnancy state
[123]
Reduced during second and third trimester of pregnancy compared to non-pregnancy women [129]