Table 2 The results of Meta-regression analysis.

	Coef.	t-Value	p	95% CI
Mean pre-pregnancy BMI	–2.10	–1.40	0.190	–5.409, 1.209
Sampling trimesters	–0.25	–0.33	0.749	–1.930, 1.423
Detecting methods	–4.21	–2.71	0.018	–7.570, –0.850
Mean age	–3.02	–2.38	0.035	–5.783, –0.253
Fasting sample	–4.18	–1.75	0.103	–9.333, 0.973

BMI: Body mass index; Coef: Coefficient; CI: Confidence interval.