[Association between hyperemesis gravidarum and fetal growth restriction]

To estimate the association between hyperemesis gravidarum (HG) and the risk of fetal growth restriction (FGR), and the possible mechanisms by which HG contributing to the risk of FGR.

The maternal socio-demographic characteristics, hyperemesis gravidarum, food intake changes and psychological stress during pregnancy of 2 522 women were assessed through questionnaires. The neonatal outcome data were obtained from medical records.

Women with HG were combined with higher psychological stress, including pregnancy related anxiety during first trimester, anxiety and depression in the third trimester, and with lower gestational weight gain compared with women without HG. In the multiple logistic regression model, FGR was significantly associated with premature delivery (RR = 1.94, 95% CI 1.05-3.56), female infants (RR = 2.50, 95% CI 1.67-3.76), less milk products intake during pregnancy (RR = 1.87, 95% CI 1.10-3.18), lower scores of anxiety during first trimester (RR = 2.05, 95% CI 1.27-3.31), higher scores of depression in the third trimester (RR = 1.85, 95% CI 1.05-3.25), and lower gestational weight gain (RR = 1.75, 95% CI 1.04-2.95). Path model showed that women with HG are predisposed to experience less milk products intake and more psychological stress during pregnancy, which could reduced maternal weight gain, and finally result in increasing the risk of FGR.

Hyperemesis gravidarum could not independently increase the risk of FGR. However, HG is significantly associated with multiple risk factors, through which HG indirectly increased the risk of FGR. Psychological stress and food intake during pregnancy mediated the negative effects of HG on FGR.