Can I work night shifts while pregnant?

The verdict

Night shifts are not prohibited in pregnancy anywhere, and plenty of people work them throughout. But the UK has a specific legal mechanism for getting off them that is different from ordinary risk assessment, and it is the most useful thing on this page.

HSE's guidance to workers states that your employer must take account of medical advice provided by your doctor or midwife, and that this might mean making adjustments to your working conditions or hours, for example if you have any pregnancy-related medical conditions or your doctor has said you should not work nights.

That is the route. It is not a request for a favour: it is a certificate, and it triggers an employer duty.

The evidence, separately, is best described as a modest and uncertain signal rather than a clear risk, and ACOG says so itself.

What the evidence shows, with the caveats attached

ACOG's Committee Opinion on employment considerations during pregnancy is the most careful published summary, and it reports several things that pull in different directions.

On miscarriage: a meta-analysis of retrospective studies showed an increased risk of miscarriage or stillbirth with night work compared with day shifts, with a relative risk of 1.51 and a 95% confidence interval of 1.27 to 1.78. A separate meta-analysis focused on shift work found night shifts associated with early spontaneous pregnancy loss, defined as loss before 25 weeks, with an adjusted odds ratio of 1.41 and a confidence interval of 1.22 to 1.63.

Against that: the single prospective study ACOG identified showed no effect, though it only included miscarriages after 12 weeks. And no increased risk was found for mixed shift work.

ACOG's own conclusion is the sentence to hold on to: at most, there appears to be a slight to modest increased risk of miscarriage with night shift work and extensive occupational lifting, although these levels of increased risk could also be attributed to bias and confounding. It lists the methodological problems explicitly, including substantial variation in how exposures were defined, incomplete control of confounding, and potential recall bias.

On working hours generally, it reports that working more than 40 hours a week was associated with a modest increased risk overall, relative risk 1.36, but that the association was not significant when limited to higher quality studies.

So this is not a settled finding. It is a consistent-ish observational signal that the professional body reporting it declines to treat as established causation.

What is not in doubt

Fatigue is. HSE states that long hours, shift work and night work can have a significant effect on the health of pregnant workers, new mothers and their children, that they may be particularly vulnerable to work-related stressors, and that mental and physical fatigue generally increase during pregnancy and following birth.

Night work also disrupts eating patterns and sleep at exactly the point when both are already disrupted, and it interacts badly with first-trimester nausea and third-trimester insomnia.

The UK route off nights, step by step

This is worth setting out because it works differently from the general risk assessment process.

1. Tell your employer in writing that you are pregnant. HSE is clear that the individual risk assessment duty is triggered by written notification. Your employer can ask for a certificate from your doctor or midwife confirming the pregnancy, and must allow reasonable time for you to get it.
2. Get a certificate from your GP or midwife saying you should not work night shifts, if that is their view. This is separate from the pregnancy confirmation certificate.
3. Your employer must act on it. HSE says employers must take account of medical recommendations provided by a doctor or midwife.
4. The sequence then applies. Adjust conditions or hours to avoid the risk; if that is not possible, offer suitable alternative work on the same terms and conditions including pay; if that is not possible, suspend on paid leave for as long as necessary.

GOV.UK's summary of pregnant employees' rights states the same principle: where there are risks the employer should take reasonable steps to remove them, for example by offering different work or changing hours, and should suspend the employee on full pay if the risks cannot be removed.

Full pay is the point. Being moved to days is the usual and best outcome, but if your employer genuinely has no day work to offer, the alternative is not unpaid leave or resignation.

If you want to keep working nights

That is a legitimate choice, and many people make it for pay, childcare or preference. Nothing above obliges you to stop.

What is reasonable to ask for, and maps onto HSE's duties rather than being invented here:

• A proper break somewhere you can lie down. HSE requires employers to provide suitable rest facilities for pregnant workers.
• Reduced consecutive nights rather than reduced total hours, since recovery between nights is where the fatigue accumulates.
• Not being left alone on a shift. HSE names working alone among the risks employers should check.
• A review of the assessment as the pregnancy progresses. HSE requires this, and pregnancy affects dexterity, agility, coordination, speed of movement and reach.

Fatigue is also the mechanism behind the practical hazards: driving home after a night shift in the third trimester is a real risk that has nothing to do with obstetrics.

Where guidance differs

The UK provides a certificate route. A doctor's or midwife's advice that you should not work nights obliges the employer to adjust, redeploy or suspend on full pay. That mechanism does not exist in the same form in the United States.

The US frames it clinically. ACOG summarises the evidence and leaves the decision to the clinician and patient, and its committee opinion is guidance rather than an employer duty. US employment protections for pregnancy operate through different legislation and vary by state.

Neither sets a limit. No authority publishes a maximum number of night shifts, a latest gestation for night work, or a shift length limit for pregnancy. The UK mechanism is individual medical advice, not a national threshold.

Both are honest about the evidence. ACOG explicitly says the increased risks reported could be attributed to bias and confounding. HSE frames night work as a fatigue and health issue rather than as an established cause of pregnancy loss.