What you are actually going back to

Returning to work is usually treated as a logistics problem, and it is partly a recovery problem. NICE NG194 lists what a midwife should be discussing with you across the postnatal period, and it is a fair checklist of what you are carrying back to work: fatigue, pelvic floor function, nutrition and physical activity, contraception, sexual intercourse, and mental health. None of those stop being live on the day your leave ends.

Add sleep. The NHS notes that most parents cope with a certain level of tiredness, but that “if you're feeling low, bad tempered and unable to cope or enjoy things, you need to find a way of getting more sleep, or at least more rest.” Going back to work does not change the night.

The UK statutory position

These are the figures from GOV.UK, and they are the framework most UK employers build on.

Statutory Maternity Leave is 52 weeks, made up of Ordinary Maternity Leave (the first 26 weeks) and Additional Maternity Leave (the last 26 weeks).
You do not have to take 52 weeks, “but you must take 2 weeks' leave after your baby is born (or 4 weeks if you work in a factory).”
Statutory Maternity Pay is paid for up to 39 weeks: 90% of your average weekly earnings before tax for the first 6 weeks, then £194.32 or 90% of your average weekly earnings, whichever is lower, for the next 33 weeks. Tax and National Insurance are deducted.
Changing your return date requires notice. GOV.UK: “you must give your employer at least 8 weeks' notice if you want to change your return to work date.”
Your rights are protected while you are off, including pay rises, accruing holiday, and the right to return.

Entitlements differ substantially between countries, and this page describes only the scheme we could verify from an official UK source. If you are outside the UK, check your own national or state scheme rather than assuming these numbers apply.

If you are still breastfeeding

The NHS assumes many women will be: exclusive breastfeeding is recommended for around the first six months, and alongside solid food after that, so “it's likely that you'll be breastfeeding when you return to work, training or education.” Its options are:

Arrange childcare close to work so you can feed during breaks, or before and after work.
Express milk so someone else can feed your baby while you are at work.
Ask for flexible working hours arranged around your breastfeeding needs.
Combine breastfeeding and bottle feeding to fit your hours.

On the legal side, the NHS says: “before returning, you should give your employer written notification that you're breastfeeding. Your employer must then conduct a specific risk assessment.” It adds that “workplace regulations require employers to provide suitable facilities where pregnant and breastfeeding mothers can rest”, that the Health and Safety Executive recommends employers provide “a private, healthy and safe environment for breastfeeding mothers to express and store milk”, and — explicitly — that “the toilets are not a suitable place to express breast milk.”

Practicalities the NHS suggests: tell your employer or HR early so preparations can be made, have a trial run with childcare before you return, and label and date expressed milk so your childminder uses the oldest first. Storage: in a sterilised container or breast milk storage bags in the fridge for up to 5 days at 4°C or lower — or within 3 days if you are unsure of the fridge temperature or it is warmer than 4°C.

Before you go back: the health checklist

Have your postnatal check. NICE NG194 says a GP should carry out an assessment at 6 to 8 weeks after the birth, covering physical and mental health, and should respond to concerns including by referring to specialist services such as physiotherapy. The NHS notes you can request the appointment yourself, and suggests taking a list of questions.
Raise continence and prolapse. The NHS 6-week check page says to tell your doctor if you are having trouble with wind or holding in pee, or soiling yourself. A job that involves standing, lifting or a long commute makes this more pressing, not less.
Raise pain during sex, or persistent perineal pain. NICE flags that pain persisting in the first weeks is associated with depression and problems with daily functioning.
Check your cervical screening. The NHS says that if you were due for screening while pregnant, it should be rescheduled for 12 weeks after the birth.
Contraception. It is one of the things covered at the postnatal check, and you can get pregnant from 3 weeks after birth (NHS).

Building activity back before day one

If your job involves standing, lifting or a long commute, the pelvic floor is the thing to rebuild first. NICE requires that women be given information about the importance of pelvic floor exercises, how to do them and when to seek help, both before transfer to community care and at every postnatal contact, and it points clinicians to its guidance on pelvic floor dysfunction and on urinary incontinence and pelvic organ prolapse. Its 6-to-8-week assessment recommendation explicitly includes responding to concerns by referral to services such as physiotherapy — so a referral is a reasonable thing to ask for before you go back, rather than after your first bad week.

NICE also asks midwives to raise physical activity as a topic in its own right, pointing to the UK Chief Medical Officer's physical activity guidelines for women after birth. Build back before the commute is added, not afterwards.

When to call

Speak to your GP, midwife or health visitor before or shortly after returning to work if:

You cannot sleep even when your baby is asleep, or you feel tired all the time — the NHS says these can be signs of postnatal depression, along with feeling down or hopeless and not enjoying things you normally enjoy.
You are leaking urine, cannot control wind or stool, or have a heavy feeling or bulge in your vagina. The NHS says to tell your doctor at the postnatal check; NICE expects referral onward, including to physiotherapy.
You have pelvic girdle or back pain that a working day will make worse.
Sex is painful — the NHS lists this among the things to tell your doctor.
You are struggling to cope. The NHS says to talk to a GP or health visitor.

Contact your GP or midwife immediately if you have thoughts of harming yourself or your baby. Call your local emergency number (999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, or 111 in New Zealand) if you have chest pain, severe breathlessness, or sudden heavy bleeding.

Returning to Work After Maternity Leave