Table 2.

Linear regression characteristics of umbilical amino acid uptake rates and fetal weights

Amino acid		Pearson’s correlation (R)	R 2	P value	Slope	95% confidence interval
Leucine	Essential	0.829	0.687	3.43 × 10−24	4.80	4.12–5.48
Arginine	Conditionally essential	0.798	0.636	2.99 × 10−21	3.68	3.09–4.26
Glutamine	Conditionally essential	0.759	0.576	4.26 × 10−18	8.31	6.80–9.82
Phenylalanine	Essential	0.754	0.569	6.09 × 10−18	2.16	1.77–2.56
Lysine	Essential	0.748	0.559	1.62 × 10−17	2.61	2.12–3.10
Isoleucine	Essential	0.745	0.556	2.34 × 10−17	3.46	2.81–4.12
Tyrosine	Conditionally essential	0.713	0.509	2.19 × 10−15	2.10	1.67–2.54
Proline	Conditionally essential	0.689	0.474	4.49 × 10−14	3.03	2.36–3.71
Alanine	Non-essential	0.687	0.472	5.60 × 10−14	4.30	3.34–5.26
Valine	Essential	0.676	0.457	1.93 × 10−13	4.77	3.68–5.86
Glycine	Conditionally essential	0.657	0.432	1.45 × 10−12	4.46	3.39–5.54
Histidine	Essential	0.648	0.420	3.91 × 10−12	0.88	0.66–1.10
Tryptophan	Essential	0.635	0.403	1.40 × 10−11	0.74	0.55–0.93
Methionine	Essential	0.597	0.356	4.35 × 10−10	1.31	0.94–1.69
Threonine	Essential	0.594	0.353	5.27 × 10−10	2.72	1.94–3.49
Cystine	Conditionally essential	0.294	0.086	0.0047	0.25	0.08–0.42
Ornithine	Non-essential	0.274	0.075	0.0085	0.39	0.10–0.68
Asparagine	Non-essential	0.216	0.047	0.0394	0.78	0.04–1.53
Taurine	Conditionally essential	0.026	0.001	0.8093	0.06	− 0.44 to 0.56
Citrulline	Non-essential	− 0.077	0.006	0.4708	− 0.23	− 0.87 to 0.40
Aspartate	Non-essential	− 0.079	0.006	0.4566	− 0.11	− 0.41 to 0.18
Serine	Non-essential	− 0.170	0.029	0.1074	− 1.12	− 2.49 to 0.25
Glutamate	Non-essential	− 0.763	0.583	1.40 × 10−18	− 4.92	− 5.80 to − 4.04

Pearson’s correlation was used to assess the correlation between umbilical amino acid uptake rates and fetal weight