Today, 10:46 AM
I think it makes the most sense to plan to pump once while you are at work. If you come back to work with this understanding, then you can always stop taking this pump session later if you find it is not needed. If you come back and are not taking a pump break, and find yourself getting full while you are at work, and later want to add a pump break, that may be be more difficult.
If you cannot pump, not even in your car on a regular break, then I would suggest pay close attention to how you feel while at work. Regular milk removal is vital not only for your milk production, but for your immediate health. If you begin to feel full at work, that possibly could lead to plugs or even mastitis- a breast infection that will make you feel very ill and unable to work for a couple days at least. So to protect your health, if you cannot pump, you may need to find a way to hand express during your work day to relieve the pressure. This could be done during a visit to the restroom. You might find it impossible to save the expressed milk, but that is entirely secondary. What is most important is relieving that pressure.
I would also suggest, if you are not pumping while at work, encourage baby to nurse a little more often while you are at home for a while at least. This will help to offset any possible issues with milk production.
Now, some moms of 4 month olds can go 5 hours without pumping or nursing or hand expressing once a day with no issues at all. Others are going to...