. 2006 Nov 9;64(4):228–243. doi: 10.1136/oem.2006.026872

Table 1 Features of the studies included in the review.

First author, (year)	Location	Study period	Study design	Exposure(s)	Method of exposure assessment	Outcome(s)
Ahlborg GJ (1990)⁵	Orebro, Sweden	1980–3	Prospective cohort	Lifting	Self‐administered questionnaire after delivery; exposure validated by hygienist in a subgroup	Preterm delivery (<37 weeks)LBW (<2500 g)LBW adjusted for gestational age
Axelsson G (1989)⁶	Sweden	1980–4	Cross‐sectional	Shift work	Mail questionnaire	Birth weight (continuous)
Berkowitz GS (1983)⁷	New Haven, USA	1977–8	Case–control, hospital based	Working hours	Expert interview after delivery	Preterm delivery (<37 wks)
				Standing
				Lifting
Bodin L (1999)⁸	Sweden	1980–7	Cross‐sectional	Working hours	Mail questionnaire	Preterm delivery (<37 weeks)
				Shift work		LBW (<2500 g)
						SGA ⩽(<10th centile)
						Birth weight (continuous)
Brink‐Henriksen T (1995)⁹,¹⁰	Denmark	1989–91	Prospective cohort	Working hours Standing	Self‐administered questionnaire during pregnancy	Preterm delivery (<37 weeks)Birth weight (continuous)
Brink‐Henriksen T (1995)⁹,¹⁰	Denmark	1989–91	Prospective cohort	Lifting	Self‐administered questionnaire during pregnancy
Cerón‐Mireles P (1996)¹¹	Mexico City, Mexico	1992	Cross‐sectional	Working hours	Personal interview, soon after delivery	Preterm delivery (<37 weeks)
				Standing		SGA (⩽10th centile)
				Physical activity
Florack EIM (1995)¹²	The Netherlands	1987–9	Prospective cohort	Lifting	Personal interview, before pregnancy	Gestational age (in weeks vs expected term)
Florack EIM (1995)¹²	The Netherlands	1987–9	Prospective cohort	Physical activity	Personal interview, before pregnancy	Birth weight (continuous)
Fortier I (1995)¹³	Quebec, Canada	1989	Cross‐sectional	Working hours	Telephone interview after delivery (median 6 weeks)	Preterm delivery (<37 weeks)
				Shift work		SGA (<10th centile)
				Standing
				Lifting
				Physical activity
Hanke W (1999)¹⁴	Lodz, Poland	1996–7	Cross‐sectional	Shift work	Interview, few days after delivery	SGA (<10th centile)
				Standing
				Physical activity
Hartikainen‐Sorri AL (1989)¹⁵	Finland	1982	Case–control, hospital based	Shift work	Mail questionnaire within 1year of delivery	Preterm delivery (<37 wks)
				Standing
				Physical activity
Hatch M (1997)¹⁶	USA	1987–9	Prospective cohort	Working hours	Telephone interview, mail questionnaire	LBW (⩽3000 g).Birth weight (continuous)
				Standing		LBW (⩽3000 g).Birth weight (continuous)
				Lifting
				Physical activity
Hickey CA (1995)¹⁷	USA	1985–8	Prospective cohort	Working hours	Self‐administered questionnaire during pregnancy	Preterm delivery (<37 weeks)
				Standing
				Physical activity
Homer CJ (1990)¹⁸	USA	1979–83	Cross‐sectional	Physical activity	Derived from job title, using a validated physical effort scale	Preterm delivery (<37 weeks)
						LBW (<2500 g)
						Birth weight (continuous)
Irwin DE (1994)¹⁹	USA	1987–9	Cross‐sectional	Standing	Based on job title using military data of activity	Gestational hypertension and pre‐eclampsia
				Lifting
				Physical activity
Klebanoff MA (1990)²⁰	USA	1985	Cross‐sectional	Working hours	Mail questionnaire after delivery, (non‐respondents contacted by telephone)	Preterm delivery (<37 weeks)
						SGA (<10th centile)
						Birth weight (continuous)
Klebanoff MA (1990)²¹	USA	1984–7	Prospective cohort	Standing	Face‐to‐face interview	Preterm delivery (<37 weeks)
Klebanoff MA (1990)²¹	USA	1984–7	Prospective cohort	Physical activity	Face‐to‐face interview	Birth weight (continuous)
Landsbergis PA (1996)²²	USA	1987–9	Prospective cohort	Working hours	Telephone interview and mail update	Gestational hypertension and pre‐eclampsia
Landsbergis PA (1996)²²	USA	1987–9	Prospective cohort	Physical activity	Telephone interview and mail update	Gestational hypertension and pre‐eclampsia
Launer LJ (1990)²³	Guatemala	1984–6	Prospective cohort	Standing	Face‐to‐face interview	Preterm delivery (<37 weeks)
Launer LJ (1990)²³	Guatemala	1984–6	Prospective cohort	Physical activity	Face‐to‐face interview	SGA (⩽10th centile)
Luke B (1995)²⁴	USA	From 1980	Case–control, population based	Working hours	Mail questionnaire	Preterm delivery (<37 weeks)
				Shift work
				Standing
				Physical activity
Magann EF (1996)²⁵	Australia	1989–91	Prospective cohort	Physical activity	Self‐administered questionnaire	Preterm delivery (<37 weeks)
						Birth weight (continuous)
						SGA (<3rd and <10th centiles)
Magann EF (2005)²⁶	San Diego, USA	Not specified	Prospective cohort	Standing	Face‐to‐face interview	Preterm delivery (<37 weeks)
Magann EF (2005)²⁶	San Diego, USA	Not specified	Prospective cohort	Lifting	Face‐to‐face interview	SGA (intrauterine growth retardation, undefined)
Mamelle N (1984)²⁷	France	1977–78	Cross‐sectional	Working hours	Face‐to‐face interview	Preterm delivery (<37 weeks)
				Shift work
				Standing
				Physical activity
Marcoux S (1999)²⁸	Quebec, Canada	1984–6	Case–control, hospital based	Working hours	Face‐to‐face interview a few days after delivery	PIH
McDonald AD (1988)²⁹ and Armstrong BG (1989)³⁰	Montreal, Canada	1982–4	Cross‐sectional	Working hours	Interview after delivery	Preterm delivery (<37 weeks)
				Shift work		LBW (⩽2500 g)
				Standing
				Lifting
				Physical activity
Meyer BA (1985)³¹	USA	1981	Case–control, population based	Standing	Based on job title according to an expert validated database	LBW (<2500 g)
Misra DP (1998)³²	USA	1988–9	Prospective cohort	Shift work	Face‐to‐face or telephone interview	Preterm delivery (<37 weeks)
				Standing
				Lifting
Newman RB (2001)³³	USA	Not specified	Prospective cohort	Standing	Face‐to‐face interview	Preterm rupture of membranes (<37 weeks)
Newman RB (2001)³³	USA	Not specified	Prospective cohort	Physical activity	Face‐to‐face interview	Preterm rupture of membranes (<37 weeks)
Nurminen T (1989)³⁴,³⁵	Finland	1976–82	Cross‐sectional	Shift work	Face‐to‐face expert interview 2–4 months after delivery	Preterm delivery (<37 weeks) SGA (⩽10th centile)
				Standing		Gestational hypertension
				Physical activity
Peoples‐Sheps MD (1991)³⁶	USA	1980	Cross‐sectional	Working hours	Derived by job title and mail interview	Preterm delivery (<37 weeks)
Peoples‐Sheps MD (1991)³⁶	USA	1980	Cross‐sectional	Physical activity	Derived by job title and mail interview	LBW (<2500 g)
Rabkin CS (1990)³⁷	London, England	1982–4	Prospective cohort	Working hours	Face‐to‐face expert interview	Birth weight (continuous)
Rabkin CS (1990)³⁷	London, England	1982–4	Prospective cohort	Physical activity	Face‐to‐face expert interview	Birth weight (continuous)
Pompeii LA (2005)³⁸	North Carolina, USA	1995–2000	Prospective cohort	Working hours	Telephone or face‐to‐face interview	Preterm delivery (<37 weeks)SGA (<10th centile)
				Shift work		Preterm delivery (<37 weeks)SGA (<10th centile)
				Standing
				Lifting
Ramirez G (1990)³⁹	USA	1981–4	Cross‐sectional	Physical activity	Military records	Preterm delivery (⩽37 weeks).
Rao S (2003)⁴⁰	Pune, India	1994–6	Prospective cohort	Physical activity	Interview before delivery	Preterm delivery (<37 weeks)
Rao S (2003)⁴⁰	Pune, India	1994–6	Prospective cohort	Physical activity	Interview before delivery	Birth weight (continuous)
Saftlas AF (2004)⁴¹	Connecticut, USA	1988–91	Prospective cohort	Standing	Face‐to‐face expert interview	Gestational hypertension and pre‐eclampsia
Saurel‐Cubizolles MJ (1985)⁴²	France	1979–81	Cross‐sectional	Physical activity	Face‐to‐face expert interview after delivery	Preterm delivery (<36.5 weeks)
						LBW (<2500 g)
						Gestational hypertension
Saurel‐Cubizolles MJ (1987)⁴³	France	1981	Cross‐sectional	Working hours	Face‐to‐face expert interview after delivery	Preterm delivery (<37 weeks)
				Shift work		LBW (<2500 g)
				Standing
				Lifting
				Physical activity
Saurel‐Cubizolles MJ (1991)⁴⁴	France	1987–8	Cross‐sectional	Working hours	Face‐to‐face expert interview after delivery	Preterm delivery (<37 weeks)
				Standing
				Lifting
				Physical activity
Saurel‐Cubizolles MJ (2004)⁴⁵	16 European countries	1994–7	Case–control hospital based	Working hours	Interview after delivery	Preterm delivery (<37 weeks)
				Shift work
				Standing
				Lifting
Savitz DA (1996)⁴⁶	USA	1988	Cross‐sectional	Working hours	Mail or telephone questionnaire	Preterm delivery (<37 weeks)
						VLBW (<1500 g)
						MLBW (1500–2499 g)
						SGA (<10th centile)
Schramm WF (1996)⁴⁷	Missouri, USA	1989–91	Case–control, population based	Standing	In‐hospital interview or mail questionnaire	VLBW (<1500 g)
Schramm WF (1996)⁴⁷	Missouri, USA	1989–91	Case–control, population based	Lifting	In‐hospital interview or mail questionnaire	MLBW (1500‐2499 g)
Spinillo A (1995)⁴⁸	Pavia, Italy	1990–4	Case–control study, hospital based	Physical activity	Face‐to‐face expert interview	Pre‐eclampsia
Stinson JC (2003)⁴⁹	USA	Not specified	Prospective cohort	Shift work	Self‐administered questionnaire during pregnancy	Preterm delivery (<37 weeks)
Stinson JC (2003)⁴⁹	USA	Not specified	Prospective cohort	Physical activity	Self‐administered questionnaire during pregnancy	Preterm delivery (<37 weeks)
Tafari N (1980)⁵⁰	Addis Ababa, Ethiopia	1976–7	Cross‐sectional	Physical activity	Face‐to‐face interview	Birth weight (continuous)
Teitelman AM (1990)⁵¹	New Haven, USA	1980–2	Prospective cohort	Standing	Based on job title	Preterm delivery (<37 weeks)
						Gestational age (in weeks)
						LBW (<2500 g)
						Birth weight (continuous)
Tuntiseranee P (1998)⁵²	S Thailand	1994–5	Prospective cohort	Working hours	Face‐to‐face expert interview at 17 and 32 weeks	Preterm delivery (<37 weeks)
				Standing		LBW (⩽2500 g)
				Lifting		SGA (<10th centile)
				Physical activity
Wergeland E (1997)⁵³ and (1998)⁵⁴	Norway	1989	Cross‐sectional	Working hours	Self‐administered questionnaire after delivery	LBW (<2500 g)Birth weight (continuous) pre‐eclampsia
				Shift work		LBW (<2500 g)Birth weight (continuous) pre‐eclampsia
				Standing
				Lifting
Xu X (1994)⁵⁵	Anhui, China	1992	Prospective cohort	Shift work	Face‐to‐face interview	Preterm delivery (<37 weeks)
						LBW (<2500 g)
						Birth weight (continuous)
Zhu JL (2004)⁵⁶	Denmark	2004	Prospective cohort	Shift work	Telephone interview during pregnancy	Preterm delivery (<37 weeks), LBW (<2500 g)
Zhu JL (2004)⁵⁶	Denmark	2004	Prospective cohort	Shift work	Telephone interview during pregnancy	SGA (<10th centile)
Zuckerman BS (1986)⁵⁷	Boston, USA	1977–9	Cross‐sectional	Standing	Face‐to‐face interview after delivery	Gestational age (weeks)
Zuckerman BS (1986)⁵⁷	Boston, USA	1977–9	Cross‐sectional	Standing	Face‐to‐face interview after delivery	Birth weight (continuous)

LBW, low birthweight; MLBW, moderately low birthweight; ref, reference; SGA, small for gestational age; VLBW, very low birthweight.