Pumping schedule and breast milk storage

How pumping affects your supply

Your body makes milk in response to milk being removed. The more often milk is removed, by your baby or a pump, the more milk you make (NHS Healthier Together). That’s why a pumping schedule usually copies how often a baby would feed: about 8–12 times in 24 hours in the early weeks and months (CDC).

There’s no single right schedule. What matters most is how often you pump across the whole day and night, and that you don’t go too long between sessions.

If you’re pumping instead of breastfeeding

This applies if your baby can’t latch, is in special care, or you’ve chosen to feed expressed milk.

• Aim for 8–10 sessions in 24 hours, including at least one overnight, to build a full supply (NHS Healthier Together). Another NHS trust suggests 8–12 times a day.
• Avoid long gaps: no more than about 4 hours during the day and 6 hours at night (Guy’s and St Thomas’ NHS).
• Pump at least once during the night. Prolactin, the hormone that makes milk, is released at night, and Guy’s and St Thomas’ NHS suggests a session between 2am and 4am.
• You don’t need fixed times. Sessions can be closer together at some parts of the day and further apart at others.

An example 24-hour schedule (8 sessions, roughly every 3 hours):

• 6am, 9am, 12pm, 3pm, 6pm, 9pm, midnight, and one session in the early hours

If your baby is premature or in the hospital, follow the neonatal team’s advice on pumping and milk storage, which can be stricter (NHS).

If you’re going back to work

• Pump about as often as your baby would feed. The NHS says you might need to express at least every 3 hours when you’re first away from your baby. The AAP says most parents step away 1–3 times a day.
• Practice first. Do a few trial runs before your first day back (NHS).
• Start mid-week if you can, so the first week is short (AAP).
• Plan a private space. In the US, the AAP suggests working with your employer to find a space if there’s no lactation room. In the UK, the NHS says your employer must give you somewhere to rest, and you shouldn’t have to express in a toilet.
• Pack the night before: pump, cooler bag with ice packs, breast pads, snacks and a spare top (AAP).

An example work day (8 hours away):

• Breastfeed before you leave
• Pump mid-morning, around lunch, and mid-afternoon
• Breastfeed when you get home, and on cue in the evening and on days off

How long each session takes

• Keep going until the flow slows right down. With hand expressing, the NHS suggests switching breasts until milk only drips slowly or stops.
• If you’re trying to increase your supply, the AAP suggests pumping more often, for at least 10 minutes a session, even if the milk stops flowing before then.
• Double pumping (both breasts at once with an electric pump) saves time and can help increase supply (NHS Healthier Together).
• Comfort matters. Build suction up slowly, and ask about a different funnel size if needed. A pump should never cause bruising or pinch your nipple (NHS).
• Relaxing helps milk flow. Warmth on your breasts, a gentle massage, or looking at a photo of your baby may help (NHS, AAP).

If your supply drops

The AAP says a drop in supply is common for working parents, and is most often caused by skipped sessions or sessions that are too short. A pump may also remove less milk than a baby who feeds well.

• Add sessions, or make them a little longer.
• When you’re with your baby, offer the breast at least every 2–3 hours, and feed on cue on days off (AAP).
• Get help early. A lactation consultant, your pediatrician or your OB can help.Call the National Breastfeeding Helpline (0300 100 0212, 24 hours a day), or ask your midwife or health visitor.A lactation consultant, midwife or your doctor can help.

How long breast milk keeps

Storage times differ between the US and UK. Follow the guidance for where you live, and when in doubt, use the shorter time.

CDC (US)

• Room temperature (77°F / 25°C or cooler): up to 4 hours
• Fridge: up to 4 days
• Freezer: about 6 months is best; up to 12 months is acceptable
• Insulated cooler with frozen ice packs: up to 24 hours

NHS (UK)

• Fridge at 4°C or colder: up to 8 days, at the back of the fridge. If your fridge is warmer (5–10°C) or you’re not sure, use within 3 days.
• Ice compartment of a fridge: up to 2 weeks
• Freezer at -18°C or colder: up to 6 months
• Cool bag with ice packs: up to 24 hours, for milk already cooled in the fridge
• Room temperature: the NHS website doesn’t give a time. Guy’s and St Thomas’ NHS gives up to 6 hours.

Storage tips

• Use breast milk storage bags or clean, food-grade glass or plastic containers with tight lids. Don’t use disposable bottle liners or ordinary plastic bags (CDC).
• Label each container with the date it was expressed (CDC, NHS).
• Store milk at the back of the fridge or freezer, not in the door (CDC).
• If you won’t use fresh milk within 4 days, freeze it right away (CDC).
• Freeze in small amounts, 2–4 oz (60–120 ml) or one feed’s worth, and leave about 1 inch (2.5 cm) at the top because milk expands (CDC).
• Use the oldest milk first (CDC).

Thawing and warming

• Thaw in the fridge overnight, or in a bowl of warm water, or under warm running water (CDC, NHS).
• Never thaw or warm breast milk in a microwave or on the stove. It creates hot spots that can burn your baby’s mouth (CDC, NHS).
• Milk doesn’t need warming. Your baby can drink it cold or at room temperature (CDC, NHS).
• Swirl gently to mix fat that has separated.
• Never refreeze milk once it has thawed (CDC, NHS).
• CDC: use milk thawed in the fridge within 24 hours of fully thawing. Once milk is at room temperature or warmed, use it within 2 hours.
• NHS: use defrosted milk straight away. NHS Healthier Together says to use it within 12 hours of taking it out of the freezer.
• Leftovers after a feed: the CDC says that if your baby doesn’t finish the bottle, use the leftover milk within 2 hours, then throw it away. The NHS says that once your baby has drunk from a bottle, use it within 1 hour, and throw away anything left over.

Keep your pump clean

The CDC says germs can grow quickly in milk left on pump parts. After every session:

• Store the milk straight away in the fridge, freezer or a cooler bag with ice packs.
• Take the pump kit apart, rinse milk-contact parts under running water, and wash them as soon as you can with ordinary dish soap (not antibacterial soap), by hand in a basin used only for feeding items or in the dishwasher (CDC).
• Let everything air-dry thoroughly on a clean, unused dish towel or paper towel before you store it. Don’t rub or pat it dry.
• Sanitize parts, the bottle brush and the wash basin at least once a day (steam, boiling for 5 minutes, or a dishwasher with hot water and a heated drying or sanitize cycle), especially if your baby is under 2 months, was born early, or has a weakened immune system.
• Tubing that milk doesn’t touch doesn’t need routine cleaning. If there are water droplets in it after a session, run the pump for a few minutes with the tubing still attached until it’s dry. Throw away tubing that has milk or mold inside it (CDC).

The NHS says to clean and sterilize the pump and containers before you use them.

Where US and UK advice differs

• Fridge: CDC up to 4 days; NHS up to 8 days at 4°C or colder, or 3 days in a warmer fridge.
• Freezer: CDC about 6 months best, up to 12 months acceptable; NHS up to 6 months at -18°C.
• Room temperature: CDC up to 4 hours; NHS trusts up to 6 hours.
• Leftovers after a feed: CDC: use milk left in the bottle within 2 hours, then throw it away. NHS: once your baby has drunk from the bottle, use it within 1 hour, then throw away anything left over.
• Thawed milk: CDC within 24 hours of fully thawing in the fridge; NHS use straight away (NHS Healthier Together: within 12 hours of leaving the freezer).
• Cleaning: CDC says daily sanitizing may not be needed for older, healthy babies if parts are cleaned carefully after each use; the NHS says to sterilize.

See also how much breast milk or formula and weaning from the bottle.