Effects of Liver Enzyme Levels During Pregnancy on Birth Weight.

Objectives: To investigate the association between maternal liver enzyme concentrations during pregnancy and the risk of abnormal birth weight.

Methods: This is a prospective birth cohort study querying the pregnant women from Fujian Maternal and Child Health Hospital, affiliated with Fujian Medical University, China. Liver enzyme levels, including gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), were measured in the first and third trimesters, and changes in liver enzyme levels were calculated based on these measurements. The outcomes were birth weight, small for gestational age (SGA), large for gestational age (LGA), low birth weight (LBW), and macrosomia.

Results: The study analyzed 19,003 singleton pregnancies with live births. The mean age of the pregnant individuals was 30.3 ± 3.9 years, 18,594 patients (97.8%) were Han. GGT in the first trimester is positively correlated with the risks of macrosomia and LBW, mediated through gestational diabetes mellitus (GDM) and gestational age at birth, respectively. Nonlinear regression models suggested that there was a linear relationship of liver enzyme levels during pregnancy with LBW and SGA (P for non-linear > 0.05). According to regression analysis, changes in liver enzyme levels during pregnancy were negatively correlated with birth weight, LGA, and macrosomia, and positively correlated with the risk of SGA. Similar results were found for liver enzymes in late pregnancy.

Conclusions: The concentration and even the changes of liver enzymes during pregnancy may influence the fetus's birth weight to different degrees. Thereby, monitoring liver enzyme levels during pregnancy could help prevent abnormal fetal development.