Table 3.

Examples of metabolomics studies associated with preterm birth.

Sample specimen	Participants (n)	Outcomes	Analytical platforms	Metabolites	Statistical analysis	References
Urine (end of the first trimester)	464 (88 spont. PB, 26 ind. PB)	Preterm birth (spontaneous and induced), control	NMR	Spontaneous PB associated with increased urine lysine, clinically induced PB was associated with in overweight and obese women and increased resonance in a N-acetyl glycoprotein	95% confi.int., AUC for SPB: 58.8-59.4%, for IPB: 66%	[45]
Cervicovaginal fluid	219	Preterm birth, controls	NMR	Higher lactate level in term ALR group compared to term and preterm AHR women, acetate was increased in preterm compared to the term group for SYM and AHR group	P<0.05, acetate integrals in PTB versus term for AHR and SYM group: predictive of preterm birth <37 gestational weeks is AUC of 0.78, acetate integrals in PTB versus term Sym group: delivery within 2 weeks of index assessment AUC of 0.84	[57]
Cervicovaginal secretions	15 (5 Spont. PB)	Preterm birth, control	UPLC-QTOF-MS	17 markers were observed to distinguish between preterm birth and control groups; further research is needed	P<0.05	[56]