Biodemographic Analysis of Factors Related to Perinatal Mortality in Portugal (1988–2011)

Table 2

Stillbirth rates ×1000 (S.B.) by category group for each variable studied (1988–2011).

Variable	Group	Total	S.B. rate
Duration of gestation (weeks)	22–31	4887	593.820
	32–36	15058	137.336
	37–41	184945	13.691
	>41	838	194.511
Maternal age (years)	<20	173046	4.432
	20–29	1426046	4.889
	30–39	1013607	6.564
	40–49	62862	15.287
Birth weight (grams)	<1500	27625	227.982
	1500–1249	163634	24.341
	2500–4000	2323280	1.867
	>4000	151848	2.127
Sex	Male	1379784	6.095
	Female	1297595	5.724
Type of delivery	Single	2615518	5.711
	Multiple	61968	16.266
Parity	1st	1410194	3.182
	2nd or more	1259135	2.981
Marital status	In couple	1161861	3.903
	Not in couple	477666	6.048

Duration of gestation: 1996–2009 is not considered. Marital status: values since 1997.