My breasts are a size 34/37H and looking at reduction but don't know what size I should consider?

Thank you for your question. Based on your description you may be an excellent candidate for breast reduction surgery at some point; this operation tends to be one of the most patient pleasing operations we perform. Whether you choose to have this operation done now or after you complete pregnancies will be a personal decision based on many factors that you should discuss with your plastic surgeon.
 I would suggest that you do your due diligence and select a plastic surgeon carefully. Ask to see lots of examples of their work helping patients similar to yourself.
 It will be very important for you to communicate your goals, concerns, and questions with your plastic surgeon. I would suggest that you write these down before your preoperative appointment.
In my practice, I ask patients to collect "goal  pictures”  of breasts which they like, breasts that are too big, and breasts that are too small as well.  I find that the use of pictures is more helpful than the words “natural” or "proportionate” etc., which can mean different things to different people.  Discussing goals in terms of cup sizes can also be a source of miscommunication.
Many of my patients choose to have enough breast tissue removed to help alleviate symptoms while retaining enough breast tissue to remain proportionate to the remainder of  bare torso. Again, preoperative communication will be critical.
 I hope this, and the attached link, helps.

Thank you for your question, it is difficult to provide precise advice without at least pictures. There is generally a limit of how much smaller you can be after breast reduction. Please look to see a board certified plastic surgeon with expertise in this procedure and see their before and after pictures from patients similar to you.

really don't match well.  So if you're dead set on fully breast feeding, be done with having children before having a reduction.  As for size, my patients can choose between aggressive, normal and conservative resections.  I don't promise a cup size and we accept whatever results from what they have chosen.  Conservative resections are designed to simply meet the insurance company minimums.