Hi D.
My thyroid became extremeky underactive after my first pregnancy 8 years ago. I've never heard of anything called "silent" postpartum thyroid...does that mean you have no obvious symptoms? Regardless, make sure you follow your bloodwork closely for the first year. Don't accept any doctor putting you on medication and then just saying he'll see you in a year. I would get it checked every 4 months for that first year and pay close attention to your body, mind and energy levels. If your thyroid is underactive, they will most likely put you on a synthetic thyroid hormone (Synthroid is the standard and much more effective than the generic). If your thyroid is underactive, there is a different kind of treatment for that (a different med and possible other methods to suppress your thyroid). I have researched thyroid issues extensively over the past several years, and have also practiced natural remedies in conjunction with synthroid. In the beginning of my third preganacy (which was in the last year and 6+ years after my first two), I noticed feeling very jittery. I had already reduced my old dose of synthroid significantly (alternative measures, time, hormones?), but suddenly I felt very "overactive". The doctor reduced my dose again and we followed it throughout the whole pregnancy. I am at the lowest possible dose of synthroid now and am thrilled. I thought I would be taking the same dose forever...that is what is typical or having to increase it. And if I had to, that wouldn't have been the very worst thing to have to deal with (so many people have much worse). The pregnancy hormones surely had something to do with it though, so I am keeping an eye on it again---I am only 6 months postpartum and it could still change again since my hormones are not completely back to normal.
My advice would be to find a good Endocrinologist, make sure they do a full panel of bloodwork, monitor it every four months until your numbers have leveled into a normal range for at least 6 months straight, pay attention to typical symptoms (hair loss, weight gain/loss, fatigue or jitters, etc...you can symptom lists online), and absolutely read up on the natural/supplemental ways to help your thyroid.
By the way, I have a great doctor who is a holistic MD (the best of both worlds) if you need someone in the Bloomfield/W. Bloomfield area.
Good luck and no worries...it is a very manageable issue.