Difference in risk of preterm and small-for-gestational-age birth depending on maternal occupations in Japan

Okui, Tasuku

doi:10.1186/s13104-023-06539-0

BMC Research Notes

Table 1 Number of live births, preterm births, and SGA births and rates of preterm and SGA births for each of the characteristics

From: Difference in risk of preterm and small-for-gestational-age birth depending on maternal occupations in Japan

		Preterm birth				SGA birth
	Number of live births	Number	Rate (%)	p-value ^a	Number of infants born between 22–41 weeks	Number	Rate (%)	p-value ^a
Total	997,600	46,685	4.68		995,473	51,603	5.18
Maternal age group				< 0.001				< 0.001
Under 20 years	11,907	659	5.53		11,882	624	5.25
20–24 years	84,431	3,581	4.24		84,208	4,422	5.25
25–29 years	259,444	10,230	3.94		258,890	13,185	5.09
30–34 years	362,287	16,076	4.44		361,535	18,223	5.04
35–39 years	225,745	12,401	5.49		225,282	11,939	5.30
40 years or more	53,786	3,738	6.95		53,676	3,210	5.98
Maternal nationality				< 0.001				< 0.001
Japanese	974,010	45,429	4.66		971,954	50,932	5.24
Non-Japanese	23,590	1,256	5.32		23,519	671	2.85
Sex				< 0.001				0.765
Female	486,483	19,836	4.08		485,398	25,123	5.18
Male	511,117	26,849	5.25		510,075	26,480	5.19
Parity				< 0.001				< 0.001
Primiparous	475,620	21,609	4.54		473,912	25,378	5.36
Multiparous	521,980	25,076	4.80		521,561	26,225	5.03
Wedlock status				< 0.001				< 0.001
In wedlock	972,910	44,949	4.62		970,864	49,944	5.14
Out of wedlock	24,690	1,736	7.03		24,609	1,659	6.74
Gestational age				< 0.001				< 0.001
< 32 weeks	5,672	5,672	100.00		5,666	1,173	20.70
32–36 weeks	41,013	41,013	100.00		41,013	3,636	8.87
>= 37 weeks	950,915	0	0.00		948,794	46,794	4.93
Birth weight				< 0.001				< 0.001
1499 g or less	5,841	5,786	99.06		5,835	2,337	40.05
1500–2499 g	75,561	23,763	31.45		75,546	29,988	39.70
>=2500 g	916,198	17,136	1.87		914,092	19,278	2.11
Household occupation				< 0.001				< 0.001
Farmer	12,789	608	4.75		12,755	642	5.03
Self-employed worker	71,471	3,414	4.78		71,301	3,662	5.14
Full-time worker 1 ^b	332,563	15,703	4.72		331,852	17,859	5.38
Full-time worker 2 ^c	454,301	20,672	4.55		453,433	22,660	5.00
Others	84,339	3,867	4.59		84,131	4,301	5.11
Unemployed	20,160	1,277	6.33		20,106	1,309	6.51
Missing	21,977	1,144	5.21		21,895	1,170	5.34
Maternal occupation				0.001				< 0.001
Unemployed persons	535,812	25,135	4.69		534,739	27,325	5.11
Administrative and managerial workers	5,140	254	4.94		5,129	245	4.78
Professional and engineering workers	149,002	6,800	4.56		148,662	7,613	5.12
Clerical workers	127,405	5,915	4.64		127,135	6,727	5.29
Sales workers	32,548	1,495	4.59		32,467	1,776	5.47
Service workers	64,555	3,092	4.79		64,385	3,475	5.40
Security workers	2,904	123	4.24		2,901	116	4.00
Agriculture, forestry, and fishery workers	4,132	183	4.43		4,124	197	4.78
Manufacturing process workers	16,569	883	5.33		16,543	977	5.91
Transport and machine operating workers	1,549	74	4.78		1,547	67	4.33
Construction and mining workers	1,893	85	4.49		1,888	91	4.82
Carrying, cleaning, packaging, and related workers	1,718	97	5.65		1,712	78	4.56
Workers engaged in an unclassified occupation	12,833	555	4.32		12,800	656	5.13
Missing	41,540	1,994	4.80		41,441	2,260	5.45

SGA, small-for-gestational-age. a. p-value indicates the result of chi-square test for an association between an outcome and each variable. b. Full-time worker 1 means household of a full-time worker of a company or private shop (except for public offices) who has 1–99 employees. c. Full-time worker 2 means household of a board member or of a full-time worker who does not correspond with the full-time worker 1.

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ISSN: 1756-0500

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