Fertility experts at Southampton's teaching hospitals have discovered women who work night shifts are at greater risk of suffering miscarriages than those who work regular office hours.
The research, led by Dr Linden Stocker and Dr Ying Cheong of the University of Southampton and University Hospital Southampton NHS Foundation Trust, also found those who work alternate and changing shifts - not just nights - are more likely to take longer to conceive a child and suffer from menstrual disruption.
The team, based at the Princess Anne Hospital, assessed the impact of non-standard working schedules, which included night and mixed shifts, on the reproductive outcomes of 119,345 women.
They found almost a third of women (29%) who worked night shifts only had an increased rate of miscarriage, while 22% who worked alternate or changing shifts suffered menstrual disruption, which can cause fertility problems.
Additionally, shift workers had an 80% increased rate of subfertility, which is the term used to describe prolonged inability to conceive.
"Many women work and we already know that working shifts is a risk factor for health and social wellbeing as shift workers adopt poor sleep hygiene, suffer sleep deprivation and develop activity levels that are desynchronised from their daily routine," explained Dr Stocker, who is a clinical research fellow at the Princess Anne Hospital.
"But the adverse health impacts of shift work in early reproductive function is a new, additional finding and it provides strong initial evidence that women who are trying to conceive would benefit from assessing their work patterns."
Dr Cheong, clinical director of the Princess Anne Hospital's Complete Fertility Centre Southampton and a senior lecturer at the University of Southampton, added: "Our findings may have implications for women attempting to become pregnant as well as employers.
"But women will want to know how they can enhance their reproductive potential, not just decrease their risk of fertility problems, so we are now looking to discover the medical explanation for this in order to improve outcomes."
The study, conducted in partnership with Dr Susan Bewley at King's College London and Professor Nick Macklon of the University of Southampton, was presented at the annual conference of the European Society of Human Reproduction and Embryology today (Tuesday).
Posted on Tuesday 9 July 2013