TABLE 1.

Risk of infant death for first births to Czech women aged 18–29 years, 1986–1992

Variable	Livebirths	Person-days lived	Infant deaths	Deaths/1,000 person-years*	Infant mortality rate†
Total	350,978	126,867,531.5	3,254	9.37	9.27
Birth weight (g)
<1,500	2,041	390,948.0	996	930.53	488.00
1,500–2,499	16,097	5,589,738.5	812	53.06	50.44
2,500–3,499	220,875	80,163,936.5	1,144	5.21	5.18
3,500–4,999	111,965	40,722,908.5	302	2.71	2.70
Gestation (weeks)
25–32	3,305	822,918.5	1,079	478.91	326.48
33–36	13,076	4,553,812.5	616	49.41	47.11
37–38	40,871	14,774,416.0	385	9.52	9.42
39–41	293,726	106,716,384.5	1,174	4.02	4.00
Marital status
Single	26,027	9,379,661.0	330	12.85	12.68
Married	324,951	117,487,870.5	2,924	9.09	9.00
Education
Basic	27,090	9,752,150.5	382	14.31	14.10
Vocational	137,504	49,681,926.5	1,349	9.92	9.81
Higher	186,384	67,433,454.5	1,523	8.25	8.17
Time since birth‡
0–23 hours	350,978	350,425.5	1,105	1,151.75
1–2 days	349,873	542,378.5	464	312.47
3–6 days	349,409	1,396,706.0	404	105.65
1 week	349,005	2,441,837.5	285	42.63
2–3 weeks	348,720	4,880,605.0	176	13.17
4–7 weeks	348,544	21,946,746.0	332	5.53
8–12 weeks	348,212	31,675,349.0	250	2.88
13–51 weeks	347,962	63,651,485.0	238	1.37
52 weeks	347,724

^*Deaths divided by person-days lived multiplied by 365.25 days per year multiplied by 1,000.

^†Deaths per 1,000 livebirths.

^‡In completed units; the first column lists the number of liveborn infants who survived to the beginning of each interval.