Parameter of M4
Updating method	Intercept	Log(hCGm)	hCGrc	hCGrc2	Log(prog)
Temporal updating (SGH), FP vs IUP
No updating	5.88	−1.18	−5.56	2.05	na
Intercept recalibration	7.07	−1.18	−5.56	2.05	na
Logistic recalibration	9.12	−1.34	−6.32	1.70	na
Refitting	6.19	−0.86	−7.37	2.19	na
Penalized refitting	7.87	−1.14	−6.42	1.74	na
Refitting + rcs	24.08	−0.87	Replaced by rcs		na
Extension	10.90	−0.77	−5.49	1.65	−1.67
Penalized extension	9.84	−0.84	−5.99	1.80	−1.20
Temporal updating (SGH), EP vs IUP
No updating	0.39	−0.06	−0.26	−3.93	na
Intercept recalibration	0.99	−0.06	−0.26	−3.93	na
Logistic recalibration	5.29	−0.70	−3.31	−0.36	na
Refitting	4.01	−0.50	−4.04	0.33	na
Penalized refitting	4.86	−0.64	−3.33	−0.33	na
Refitting + rcs	14.44	−0.48	Replaced by rcs		na
Extension	7.83	−0.47	−2.66	−0.14	−1.21
Penalized extension	6.83	−0.50	−3.05	−0.05	−0.84
Geographical updating (QCCH), FP vs IUP
No updating	5.88	−1.18	−5.56	2.05	na
Intercept recalibration	6.15	−1.18	−5.56	2.05	na
Logistic recalibration	5.08	−0.82	−3.86	0.61	na
Refitting	4.74	−0.75	−4.04	0.06	na
Penalized refitting	4.86	−0.78	−3.90	0.50	na
Refitting + rcs	9.01	−0.73	Replaced by rcs		na
Extension	5.67	−0.66	−3.38	−0.06	−0.52
Penalized extension	5.45	−0.73	−3.65	0.38	−0.32
Geographical updating (QCCH), EP vs IUP
No updating	0.39	−0.06	−0.26	−3.93	na
Intercept recalibration	1.25	−0.06	−0.26	−3.93	na
Logistic recalibration	1.70	−0.20	−0.91	−1.33	na
Refitting	3.81	−0.51	−0.42	−1.59	na
Penalized refitting	3.22	−0.43	−0.67	−1.39	na
Refitting + rcs	0.79	−0.51	Replaced by rcs		na
Extension	4.61	−0.45	0.07	−1.75	−0.40
Penalized extension	3.89	−0.43	−0.41	−1.45	−0.21

hCGm the average of hCG at 48 hours and hCG at presentation, hCGrc the centered ratio of hCG at 48 hours and hCG at presentation, prog progesterone, FPUL failed pregnancy of unknown location, IUP intra-uterine pregnancy, EP ectopic pregnancy, SGH St. George’s Hospital, QCCH Queen Charlotte’s and Chelsea Hospital, rcs restricted cubic splines