Table 1

 Features of the studies included in the review

First author, (year)LocationStudy periodStudy designExposure(s)Method of exposure assessmentOutcome(s)
LBW, low birthweight; MLBW, moderately low birthweight; ref, reference; SGA, small for gestational age; VLBW, very low birthweight.
Ahlborg GJ (1990)5Orebro, Sweden1980–3Prospective cohortLiftingSelf-administered questionnaire after delivery; exposure validated by hygienist in a subgroupPreterm delivery (<37 weeks) LBW (<2500 g) LBW adjusted for gestational age
Axelsson G (1989)6Sweden1980–4Cross-sectionalShift workMail questionnaireBirth weight (continuous)
Berkowitz GS (1983)7New Haven, USA1977–8Case–control, hospital basedWorking hoursExpert interview after deliveryPreterm delivery (<37 wks)
Standing
Lifting
Bodin L (1999)8Sweden1980–7Cross-sectionalWorking hoursMail questionnairePreterm delivery (<37 weeks)
Shift workLBW (<2500 g)
SGA ⩽(<10th centile)
Birth weight (continuous)
Brink-Henriksen T (1995)9,10Denmark1989–91Prospective cohortWorking hours StandingSelf-administered questionnaire during pregnancyPreterm delivery (<37 weeks) Birth weight (continuous)
Lifting
Cerón-Mireles P (1996)11Mexico City, Mexico1992Cross-sectionalWorking hoursPersonal interview, soon after deliveryPreterm delivery (<37 weeks)
StandingSGA (⩽10th centile)
Physical activity
Florack EIM (1995)12The Netherlands1987–9Prospective cohortLiftingPersonal interview, before pregnancyGestational age (in weeks vs expected term)
Physical activityBirth weight (continuous)
Fortier I (1995)13Quebec, Canada1989Cross-sectionalWorking hoursTelephone interview after delivery (median 6 weeks)Preterm delivery (<37 weeks)
Shift workSGA (<10th centile)
Standing
Lifting
Physical activity
Hanke W (1999)14Lodz, Poland1996–7Cross-sectionalShift workInterview, few days after deliverySGA (<10th centile)
Standing
Physical activity
Hartikainen-Sorri AL (1989)15Finland1982Case–control, hospital basedShift workMail questionnaire within 1year of deliveryPreterm delivery (<37 wks)
Standing
Physical activity
Hatch M (1997)16USA1987–9Prospective cohortWorking hoursTelephone interview, mail questionnaireLBW (⩽3000 g). Birth weight (continuous)
Standing
Lifting
Physical activity
Hickey CA (1995)17USA1985–8Prospective cohortWorking hoursSelf-administered questionnaire during pregnancyPreterm delivery (<37 weeks)
Standing
Physical activity
Homer CJ (1990)18USA1979–83Cross-sectionalPhysical activityDerived from job title, using a validated physical effort scalePreterm delivery (<37 weeks)
LBW (<2500 g)
Birth weight (continuous)
Irwin DE (1994)19USA1987–9Cross-sectionalStandingBased on job title using military data of activityGestational hypertension and pre-eclampsia
Lifting
Physical activity
Klebanoff MA (1990)20USA1985Cross-sectionalWorking hoursMail questionnaire after delivery, (non-respondents contacted by telephone)Preterm delivery (<37 weeks)
SGA (<10th centile)
Birth weight (continuous)
Klebanoff MA (1990)21USA1984–7Prospective cohortStandingFace-to-face interviewPreterm delivery (<37 weeks)
Physical activityBirth weight (continuous)
Landsbergis PA (1996)22USA1987–9Prospective cohortWorking hoursTelephone interview and mail updateGestational hypertension and pre-eclampsia
Physical activity
Launer LJ (1990)23Guatemala1984–6Prospective cohortStandingFace-to-face interviewPreterm delivery (<37 weeks)
Physical activitySGA (⩽10th centile)
Luke B (1995)24USAFrom 1980Case–control, population basedWorking hoursMail questionnairePreterm delivery (<37 weeks)
Shift work
Standing
Physical activity
Magann EF (1996)25Australia1989–91Prospective cohortPhysical activitySelf-administered questionnairePreterm delivery (<37 weeks)
Birth weight (continuous)
SGA (<3rd and <10th centiles)
Magann EF (2005)26San Diego, USANot specifiedProspective cohortStandingFace-to-face interviewPreterm delivery (<37 weeks)
LiftingSGA (intrauterine growth retardation, undefined)
Mamelle N (1984)27France1977–78Cross-sectionalWorking hoursFace-to-face interviewPreterm delivery (<37 weeks)
Shift work
Standing
Physical activity
Marcoux S (1999)28Quebec, Canada1984–6Case–control, hospital basedWorking hoursFace-to-face interview a few days after deliveryPIH
McDonald AD (1988)29 and Armstrong BG (1989)30Montreal, Canada1982–4Cross-sectionalWorking hoursInterview after deliveryPreterm delivery (<37 weeks)
Shift workLBW (⩽2500 g)
Standing
Lifting
Physical activity
Meyer BA (1985)31USA1981Case–control, population basedStandingBased on job title according to an expert validated databaseLBW (<2500 g)
Misra DP (1998)32USA1988–9Prospective cohortShift workFace-to-face or telephone interviewPreterm delivery (<37 weeks)
Standing
Lifting
Newman RB (2001)33USANot specifiedProspective cohortStandingFace-to-face interviewPreterm rupture of membranes (<37 weeks)
Physical activity
Nurminen T (1989)34,35Finland1976–82Cross-sectionalShift workFace-to-face expert interview 2–4 months after deliveryPreterm delivery (<37 weeks) SGA (⩽10th centile)
StandingGestational hypertension
Physical activity
Peoples-Sheps MD (1991)36USA1980Cross-sectionalWorking hoursDerived by job title and mail interviewPreterm delivery (<37 weeks)
Physical activityLBW (<2500 g)
Rabkin CS (1990)37London, England1982–4Prospective cohortWorking hoursFace-to-face expert interviewBirth weight (continuous)
Physical activity
Pompeii LA (2005)38North Carolina, USA1995–2000Prospective cohortWorking hoursTelephone or face-to-face interviewPreterm delivery (<37 weeks) SGA (<10th centile)
Shift work
Standing
Lifting
Ramirez G (1990)39USA1981–4Cross-sectionalPhysical activityMilitary recordsPreterm delivery (⩽37 weeks).
Rao S (2003)40Pune, India1994–6Prospective cohortPhysical activityInterview before deliveryPreterm delivery (<37 weeks)
Birth weight (continuous)
Saftlas AF (2004)41Connecticut, USA1988–91Prospective cohortStandingFace-to-face expert interviewGestational hypertension and pre-eclampsia
Saurel-Cubizolles MJ (1985)42France1979–81Cross-sectionalPhysical activityFace-to-face expert interview after deliveryPreterm delivery (<36.5 weeks)
LBW (<2500 g)
Gestational hypertension
Saurel-Cubizolles MJ (1987)43France1981Cross-sectionalWorking hoursFace-to-face expert interview after deliveryPreterm delivery (<37 weeks)
Shift workLBW (<2500 g)
Standing
Lifting
Physical activity
Saurel-Cubizolles MJ (1991)44France1987–8Cross-sectionalWorking hoursFace-to-face expert interview after deliveryPreterm delivery (<37 weeks)
Standing
Lifting
Physical activity
Saurel-Cubizolles MJ (2004)4516 European countries1994–7Case–control hospital basedWorking hoursInterview after deliveryPreterm delivery (<37 weeks)
Shift work
Standing
Lifting
Savitz DA (1996)46USA1988Cross-sectionalWorking hoursMail or telephone questionnairePreterm delivery (<37 weeks)
VLBW (<1500 g)
MLBW (1500–2499 g)
SGA (<10th centile)
Schramm WF (1996)47Missouri, USA1989–91Case–control, population basedStandingIn-hospital interview or mail questionnaireVLBW (<1500 g)
LiftingMLBW (1500-2499 g)
Spinillo A (1995)48Pavia, Italy1990–4Case–control study, hospital basedPhysical activityFace-to-face expert interviewPre-eclampsia
Stinson JC (2003)49USANot specifiedProspective cohortShift workSelf-administered questionnaire during pregnancyPreterm delivery (<37 weeks)
Physical activity
Tafari N (1980)50Addis Ababa, Ethiopia1976–7Cross-sectionalPhysical activityFace-to-face interviewBirth weight (continuous)
Teitelman AM (1990)51New Haven, USA1980–2Prospective cohortStandingBased on job titlePreterm delivery (<37 weeks)
Gestational age (in weeks)
LBW (<2500 g)
Birth weight (continuous)
Tuntiseranee P (1998)52S Thailand1994–5Prospective cohortWorking hoursFace-to-face expert interview at 17 and 32 weeksPreterm delivery (<37 weeks)
StandingLBW (⩽2500 g)
LiftingSGA (<10th centile)
Physical activity
Wergeland E (1997)53 and (1998)54Norway1989Cross-sectionalWorking hoursSelf-administered questionnaire after deliveryLBW (<2500 g) Birth weight (continuous) pre-eclampsia
Shift work
Standing
Lifting
Xu X (1994)55Anhui, China1992Prospective cohortShift workFace-to-face interviewPreterm delivery (<37 weeks)
LBW (<2500 g)
Birth weight (continuous)
Zhu JL (2004)56Denmark2004Prospective cohortShift workTelephone interview during pregnancyPreterm delivery (<37 weeks), LBW (<2500 g)
SGA (<10th centile)
Zuckerman BS (1986)57Boston, USA1977–9Cross-sectionalStandingFace-to-face interview after deliveryGestational age (weeks)
Birth weight (continuous)