Your first week with the Mother's Nature™ W1

By The Zomee Team · Updated September 28, 2026 · 7 min read

Before your first session, charge both pumps, clean the washable parts, and measure each nipple with the included nipple ruler. If your new pump feels weak, flange size is usually the reason.

Your output "shifts with time of day, how recently you last nursed or pumped," says Kristen Hunter, IBCLC. One light session tells you little about your supply.

What your W1 includes

Your W1 includes two pumps, one for each side. Each has a motor, a 6 oz milk collector, a diaphragm, a duckbill valve, and a 24 mm warming breast shield.

The W1 includes five sizes: 24 mm breast shields and 15, 17, 19, and 21 mm inserts. Additional sizes available for free with Perfect Fit Promise™. An insert sits inside the breast shield and makes its tunnel smaller.

Your box also includes these parts and accessories:

Two extra duckbill valves
Two bra strap adjusters
Two magnetic charging cables
A nipple ruler, a cleaning brush, and a manual

Before your first session

Four steps get your W1 ready:

Charge both pumps: Attach a magnetic charging cable to each motor. A full charge takes about 90 minutes and gives you more than 2 hours of pumping. Don't pump while your W1 is charging.
Clean the washable parts: Wash the milk collectors, diaphragms, duckbill valves, and inserts in warm water with mild dish soap. Then submerge them in a pot of boiling water for 5 minutes, the boiling time the CDC recommends. Lift them out with tongs and let them air dry. Hand wash the warming breast shields too, but never boil them.
Measure both nipples: Use the nipple ruler to measure the widest part of the tip of each nipple, not the base. Match each side to the closest size, and if you land exactly between two sizes, start with the smaller one. Measure even if you've pumped before, because your size can change between pregnancies.
Put each pump together: Once the parts are dry, pinch the duckbill valve and insert it into the milk collector at an angle. Make sure it sits flush. Any gap reduces suction. Place the diaphragm flat side up, and press all the way around the rim to seal it. Line up the warming breast shield's four magnetic pins with the four connectors on the milk collector. Center the tunnel, then press around the edges for a tight seal. Make sure the silicone flap is closed, and slide the motor in until it clicks.

How do I start my first session?

Place each pump inside your bra with your nipple centered in the tunnel. Make sure it sits upright and flush against your breast. Gaps reduce suction and warming.

Wear a wireless, supportive bra, and tighten the straps or use the bra strap adjusters to keep each pump secure. For the best hands-free pumping, wear your W1 with our 2-in-1 Pumping Bra. Sit upright while you pump.

Press and hold the power button for 2 seconds to turn the pump on. To start warming, press and hold the warming button. A solid warming icon means the shield is connected and warming.

NatureWarm™ Technology cycles the warming breast shield between 95 and 105°F, a warmth inspired by your baby's body temperature. Warmth can help relax breast tissue and support oxytocin, the hormone behind let-down.

Once the pump is running, check your fit by feel. The tip of your nipple should feel comfortable and move freely, without rubbing, pinching, or pulling. If it rubs or pinches, try the next size up. If too much of your areola pulls into the tunnel, try the next size down.

Which mode should I start in?

You don't have to pick one. Each time you turn on your W1, it runs its recommended settings: 2 minutes of Stimulation Mode, 8 minutes of Expression Mode, and 20 minutes of 2-Phase Mode. The warming button is also the mode button, and a short press switches modes at any point.

Stimulation Mode uses short, fast pulls to trigger let-down. Expression Mode uses slower, deeper pulls to express milk. 2-Phase Mode alternates between the two, following a nursing baby's rhythm. BioBoost™ Mode follows a cluster-feeding rhythm, with longer stimulation and shorter expression.

Each mode has 12 suction levels. Turn suction up slowly, and only to a level that feels comfortable. You should never feel pain while pumping.

What do I do after each session?

Turn the pump off and keep the milk collector upright as you take it out of your bra. Lift the tab at the top of the pump and pour your milk through the angled spout into a bottle or storage bag. Our milk storage guidelines cover how long it keeps.

To remove the motor, lift it at a diagonal to release the magnetic connection. Wipe each motor clean, and never wash it or put it in water. Moisture can damage the parts inside.

Take the pump apart, using the pull tab to lift out each duckbill valve. Rinse each washable part under running water, then wash it with warm water, mild dish soap, and the cleaning brush.

Let every part dry completely before you put the pump back together. Even a little moisture can affect suction.

For extra germ removal, the CDC recommends sanitizing pump parts at least once daily, after you clean them. That matters most if your baby is less than 2 months old, was born prematurely, or has a weakened immune system. For older, healthy babies, the CDC says daily sanitizing may not be necessary if you clean the parts carefully after each use.

To sanitize the milk collectors, diaphragms, duckbill valves, and inserts, steam them in the microwave or a plug-in steam system, or boil them for 5 minutes. Check your manual first.

Common problems and fixes

Check these before you decide something is broken:

Suction feels weak: On a new pump, flange size is the usual reason, so measure again and try another of your five sizes. Also check that each duckbill valve sits flush.
The warming icon blinks or disappears: Check the pins and connectors for dirt or residue, then detach the warming breast shield and attach it again. In a very cold room, the shield can take longer to warm.
Milk leaks: Check that the silicone flap is closed, and look for tears or warping in each part.
The pump won't charge: Use only the W1's magnetic charging cables, and take each pump off its cable once it's fully charged.
Suction fades over time: The diaphragms create suction and the duckbill valves maintain it, and both wear with use. Replace the duckbill valves every 1 to 3 months and the diaphragms every 2 to 3 months, and check both more often if you sanitize daily.

Where to get help

For free help getting started with your W1, or for pump, sizing, parts, and support questions, call The Mom Line™ at 1-888-662-7159 from 9 AM to 5 PM ET, Monday to Friday. Real moms and certified lactation consultants answer it. If none of your five sizes fits, they can help you measure and request your size through our Perfect Fit Promise™.

If you think a motor or part is defective, The Mom Line can start a warranty claim, and we usually ask for a short video of the problem.

For feeding or supply concerns, talk to a lactation consultant (IBCLC). For pain, fever, or questions about your baby's weight or diapers, call your provider.

Questions moms ask

Why does my new W1 feel weak?

Flange size, most of the time. Measure the widest part of each nipple tip again, then go up a size if your nipple rubs or pinches, or down a size if too much areola pulls into the tunnel. If none of the W1's five sizes fits, our Perfect Fit Promise™ sends you a pair in your size, free.

Can I boil or microwave the warming breast shield?

No. It has internal warming wires, so hand washing is the only way to clean it. Never put it in the dishwasher, and never boil, steam, or microwave it. The parts you can boil or steam are the milk collectors, diaphragms, duckbill valves, and inserts.

How often should I sanitize my W1 parts?

The CDC recommends at least once a day, after cleaning, for extra germ removal. That matters most for a baby under 2 months old, born prematurely, or with a weakened immune system. For an older, healthy baby, the CDC says daily sanitizing may not be necessary if you clean the parts carefully after every session.

How long does the W1 battery last?

More than 2 hours of pumping on a full charge. Charging takes about 90 minutes with the included magnetic charging cables, and regular USB cables won't fit the W1.

Why does my W1 switch modes on its own?

It's following its recommended settings. Every time you turn it on, your W1 runs 2 minutes of Stimulation Mode, then 8 minutes of Expression Mode and 20 minutes of 2-Phase Mode. The warming button is also the mode button, and a short press changes modes whenever you like.

Why isn't my W1 warming up?

Press and hold the warming button, then look for a solid warming icon. If the icon blinks or disappears, check the pins and connectors for dirt or residue and attach the shield again. In a very cold room, it can take longer to warm.