Background:

night work has been associated with certain health risks. Furthermore, pregnant women may face specific risks.

Objective:

to review the scientific evidence of night work risks on pregnant women. Identify those risks and assess the effects of night work on the health of pregnant women.

Materials and methods:

a systematic review of the published literature from 2015 to 2019 in English and Spanish was performed. All studies with information related to night work and possible effects in pregnant women like hypertension, miscarriage, preterm birth or sick leave were reviewed.

Results:

4 cohort studies (quality of the evidence assessed by STROBE statement: 77.3-81.9%) and 1 case series (quality assessed by MINCIR: 68%) were included. Association between night work and an increased risk of miscarriage (adjusted HR=1.32, CI95%:1.07-1.62), sick leave (OR=1.55, CI95%:1.43-1.69) and decreased melatonin levels was found. An increased risk of hypertension after more than 4 consecutive night shifts (OR=1.41, CI95%:1.01-1.98) was found. No association between night work and risk of preterm birth was found (OR=1.03, CI95%:0.88-1.21).

Conclusion:

association between night work and certain risks on pregnant women seems to exist. However, there is no enough evidence to support it. It is considered necessary to carry out well-designed and quality studies in a wider, more diverse and representative population.