I developed hypothyroidism after our second child was born. I was told it was PPD, that it was becausing I had a nursing baby, that I was depressed because we had just moved away from our families (we were in Okinawa), etc. I even had my thyroid levels tested but, because they came out on the high end of normal, my doctor felt it wasn't a problem. In fact, "normal" is different for everyone and, just because you test on the borderline, it doesn't mean you're not having symptoms.