Soluble HLA-G concentrations in obese women during pregnancy and in cord blood

CONTEXT: Little is known about soluble HLA-G (sHLA-G) concentrations in obese pregnant women with uncomplicated pregnancies.

OBJECTIVE: To investigate the role of sHLA-G in obese pregnancies.

DESIGN: Case-control study, from 2013 to 2015.

SETTING: A tertiary care centre.

PATIENTS: 168 healthy normal weight women and 59 overweight/obese women; to avoid the effect of preeclampsia on sHLA-G concentrations, cases were further divided in two groups: 42 with normotensive pregnancy and 17 who developed preeclampsia.

INTERVENTIONS: all the women enrolled received standard antenatal care and plasma sample collections were performed.

MAIN OUTCOME MEASURES: sHLA-G concentrations during pregnancy, before delivery and in cord blood.

RESULTS: Maternal sHLA-G concentrations in overweight/obese with normotensive pregnancies increased by 14.7% (IQR=-26.4 to +89.6) in the 2nd trimester and by 19.6% (IQR=-33 to +104) before delivery and were significantly higher than in controls (p=0.024). Median cord blood sHLA-G concentrations were 53.5ng/ml (IQR=36-62.7) in the overweight/obese women with uncomplicated pregnancies (p<0.001 compared to controls) and 19.7ng/ml (IQR=7.5-36.3) in controls. Maternal concentrations of sHLA-G in the two trimesters and before delivery were significantly lower among subjects who developed preeclampsia than in controls (p<0.001) or in obese subjects with normotensive pregnancies (p<0.001).

CONCLUSIONS: sHLA-G concentratons are higher in normotensive overweight/obese women and their babies while lower in preeclamptic overweight/obese women and their cords. Obesity influences maternal and fetal sHLA-G concentrations during pregnancy, to optimize the reproductive success, while preeclampsia impairs the mother-offspring antinflammatory response.