Assessing fetal growth impairments based on family data as a tool for identifying high-risk babies. An example with neonatal mortality

Table 1 Parameters of the major and secondary components in the mixture of two Normal distributions of birth weight among preterm births (22–33 weeks) stratified by gestational age and sex

Gestational age (weeks)	22–23	24–25	26–27	28	29	30	31	32	33
Girls
Sample size	49	93	507	2017	917	1464	1721	2659	3503
μ_m: Mean major Gaussian (g)	556	713	913	1071	1216	1344	1541	1730	1934
σ_m: Std major Gaussian (g)	125	134	182	213	258	277	306	317	363
μ_s: Mean sec. Gaussian (g)	2771	3800	2141	2848	2182	3103	2556	2207	2322
σ_s: Std sec. Gaussian (g)	591	150	805	657	532	613	1244	787	755
p_s: Weight sec. Gaussian (%)	3.6	0.5	3.3	2.7	1.9	8.2	4.5	7.8	9.8
Threshold (g) &	931	1115	1459	1710	1990	2175	2459	2681	3023
Number of births above threshold	5	5	25	20	17	92	35	52	51
Boys
Sample size	49	85	422	1629	808	1176	1357	2111	2956
μ_m: Mean major Gaussian (g)	601	769	969	1148	1299	1434	1629	1828	2040
σ_m: Std major Gaussian (g)	119	150	191	224	243	298	322	335	378
μ_s: Mean sec. Gaussian (g)	2850	3479	2706	2662	2209	3301	2808	2248	3331
σ_s: Std sec. Gaussian (g)	354	991	947	978	1105	907	1433	842	551
p_s: Weight sec. Gaussian (%)	4.3	2.7	2.3	3.3	4.9	7.8	3.2	7.2	1.4
Threshold (g) &	958	1219	1542	1820	2028	2328	2595	2833	3174
Number of births above threshold	4	16	28	28	27	103	34	54	33

& The threshold was estimated as the mean μ_m of the major Gaussian distribution plus 3 times the standard deviation σ_m of the major Gaussian distribution. Birth weights above this threshold were considered as inconsistent with gestational age and excluded from the analysis.

ISSN: 1471-2393