Table 2.

Mean gestational age at delivery by different methods and country, Pearson correlation and results from Bland Altman plots

	All	Burkina Faso	Malawi	Ghana	Zambia
Mean gestational age in weeks by US (95%CI)	38.73 (38.63–38.83)	38.85 (38.67–39.03)	38.37 (38.17–38.56)	39.27 (39.06–39.48)	38.74 (38.53–38.96)
Comparison US vs LMP
N	404	10	30	46	318
Mean gestational age in weeks by LMP (95%CI)	38.41 (37.97–38.86)	40.80 (37.98–43.62)	38.61 (37.27–39.96)	40.26 (39.40–41.11)	38.05 (37.52–38.57)
Pearson r	0.38	−0.06	0.66	0.05	0.38
Mean difference in weeks	0.34	−1.81	−0.24	− 0.96	0.65
95% limit of agreement	−7.9 to 8.6	−9.7 to 6.1	−5.6 to 5.1	−7.28 to 5.36	− 7.99 to 9.28
Range of averages	25.21 to 50.14	37.86 to 44.64	27.93 to 43.00	36.07 to 44.14	25.21 to 50.14
Comparison US vs SFH
N	1624	382	581	289	372
Mean gestational age in weeks by SFH (95%CI)	38.33 (38.16–38.50)	39.19 (38.91–39.46)	36.18 (35.95–36.41)	38.07 (37.71–38.42)	41.02 (40.69–41.36)
Pearson r	0.63	0.7	0.87	0.54	0.58
Mean difference in weeks	0.4	0.34	2.19	1.23	−2.28
95% limit of agreement	−4.9 to 5.8	−4.2 to 3.5	−5.1 to 4.9	−3.86 to 6.33	−7.56 to 3.00
Range of averages	22.14 to 46.85	29.50 to 44.21	22.14 to 43.64	29.79 to 45.71	29.14 to 46.86
Comparison US vs BS
N	1538	379	553	242	346
mean gestational age in weeks by BS (95%CI)	38.07 (38.05–38.09)	38.59 (38.55–38.64)	38.47 (38.44–38.50)	38.56 (38.52–38.59)	36.19 (36.16–36.22)
Pearson r	0.31	0.35	0.52	0.45	0.16
Mean difference in weeks	0.8	0.26	−0.03	0.83	2.7
95% limit of agreement	−3.5 to 5.1	−3.6 to 4.1	−3.90 to 3.83	−2.30 to 3.95	−1.21 to 6.62
Range of averages	28.79 to 43.21	29.50 to 42.86	28.78 to 43.21	32.64 to 41.64	32.93 to 40.43