INTRODUCTION
Preterm birth (PTB), defined as birth before 37 complete gestational
weeks, accounts for about 18% of all deaths in under-five children and
35% of death among newborns1.
Evidence
have suggested that PTB was related to a serious of adverse health
outcomes during childhood and adulthood, such as neurodevelopmental
impairment, respiratory diseases, diabetes mellitus, hypertension and
cardiovascular disease2-6. Precise etiology of PTB is
still largely unknown. Emerging evidence has suggested that maternal
dyslipidemia during pregnancy might be a risk factor for
PTB7-13. A recent meta-analysis of these studies
reported that a more atherogenic maternal lipid profile including
elevated total cholesterol, triglycerides and low high-density
lipoprotein (HDL) was positively related to the risk of
PTB14.
Apolipoprotein (Apo) is a key
component of lipid metabolism and transportation. ApoA-1 is the main
structural protein component of HDL. ApoB represents the total amount of
potentially atherogenic circulating lipoproteins, including low-density
lipoprotein (LDL), very low-density lipoprotein (VLDL) and
intermediate-density lipoproteins (IDL). The ApoB/ApoA-1 ratio reflects
cholesterol balance between atherogenic and anti-atherogenic lipoprotein
particles and were thought to be a reliable parameter to reflect lipid
disturbance15.
Abundant evidence have shown that apolipoprotein levels were associated
with metabolic syndrome16, insulin
resistance17 and cardiovascular
disease15 among non-pregnant population.
Epidemiological studies suggested that serum ApoB level and ApoB/ApoA-1
ratio during pregnancy were positively related to the risk of
preeclampsia18-20,
uteroplacental acute atherosis21 and intrauterine
growth restriction22. However, evidence regarding the
association between maternal apolipoprotein levels and PTB is limited.
To our knowledge, only three previous studies have investigated the
relationship between maternal ApoA-1 and PTB with conflicting
results23-25. Furthermore, the effects of maternal
ApoB and ApoB/ApoA-1 ratio on PTB have not been studied yet.
Thus, we aim to explore the relationship between serum ApoA-1, ApoB,
ApoB/ApoA-1 ratio during pregnancy and PTB among Chinese pregnant women.