Table 1 Effect of independent variables (gestational age, prolonged rupture of membrane (PROM), inotropes, sepsis and significant patent ductus arteriosus (PDA)) on plasma NT-proBNP levels

	NT-proBNP level
	Day 1			Day 3			Day 5			Day 10
R	0.499			0.779			0.675			0.622
R²	0.162			0.558			0.392			0. 315
		β	p Value		β	p Value		β	p Value		β	p Value

Predictors
Gestational age		−0.495	0.013*		−0.046	0.750		−0.169	0.306		−0.304	0.087
PROM		−0.495	0.789		0.194	0.072		0.149	0.218		−0.104	0.416
Inotropes		0.026	0.871		0.226	0.058		0.056	0.679		0.148	0.304
Sepsis		0.170	0.239		−0.112	0.299		0.057	0.639		0.417	0.002*
Significant PDA		0.025	0.892		0.583	0.000*		0.527	0.001*		0.262	0.119

β represents the regression coefficient; R² represents the multiple correlation coefficients; *Significant p values.