Failed pregnancy. baby stop growing @6wks. which is better d&c or natural miscarriage... i don't want to have problem getting pregnant. in the future?

Talk to OB: Your obstetrician can best advise you. Generally, there are medications that can induce you to miscarry, and afterwards, an ultrasound to confirm that you have lost all of the conceptus. If not, you would then require a d&c.

Wait.: A very early pregnancy failure is best left alone. You body will take care of it with little more than a little more bleeding and cramping with your next "period". Before sensitive pregnancy tests and ultrasound, many early pregnancy failures were undiagnosed, resulting in a "late period".

Depends: There are pros and cons to each option for terminating the pregnancy. A D&C is usually a better option if you just want things completed in a timely fashion, but there are surgical risks with this method. If by "natural miscarriage" you mean allowing your body to initiate the process, it is also an option. You may have more bleeding, it can take a month to complete and you still may need a d&c.