My wife and I have had first hand experience on how thyroid problems can affect fertility. I'm not claiming to know the chemical mumbo jumbo, or the scientific name of the diseases. However I do know what to expect and what to avoid.
My wife and I met when we were young, 17, and we stopped trying not to get pregnant at 18. We had our first child two months before my 21st birthday. What we didn't know is that my wife's thyroid had become over active. We were unaware that the past few years her over active thyroid is what was making it difficult for her to get pregnant. Over the next few years her throat began getting larger. A goiter was forming and we didn't even notice.
When my son turned two, we decided it was time to have a second child. My wife got pregnant three times. The first two ended in very painful miscarriages. The third however finally stuck after a DNC, which is a scraping of the uterus, and two years of trying. During the pregnancy my wife was constantly complaining of feeling like she was on fire. She was always hot, and was having trouble keeping her weight. She ate alot and never gained much extra weight. The baby was getting most of the nutrients and what she did get her body burned off very quickly.
When the baby was born my wife had to have another c-section, her entire body reacted very badly to the surgery and she almost died. But once she had a couple of days to recover she was back on her feet and determined to be better. At this point she could barely sit down, and her heart was racing rather uncontrollably. She couldn't calm down and began complaining that her heart was palpatating. After some research on the internet we realized that she could have a thyroid disorder and we took her to the ER. The doctors were amazed to see a goiter as large as hers had gotten, and told her she definitely had Hyperthyroidism and graves disease. It was the largest that any one of them have ever seen. They did some tests on her heart and it turned out that she was near a very fatal heart attack. She was immediately put on a high dose of heart medication called Toprol XL 100 ml. As well as a thyroid pill they called TPU. I don't know what it's really called. I don't really care either, just as long as it was making her feel better.
Since then my wife has seen a doctor regularly and has been getting her blood levels checked. All with the hope that her levels would go down far enough that a doctor would be willing to treat her effectively. Her goiter has shrunk significantly and she feels some what healthier than she did. Soon she'll be treated and we'll have to deal with an all new array problems from Hypothroidism.
After all this I'll tell you what I think you should try avoid;
Avoid the heart ache of failed pregnancies.
Avoid making yourself or your spouse deal with the pain associated with pregnancy when untreated for the disorder
Avoid any strenuous activities, excluding intercourse.
Although I am a little biased against getting pregnant in this condition it's your porogative. Here are a few things to consider if you do decide or end up pregnant;
Consider getting treated for your thyroid disorder first.
Consider the genetic implications before hand.
Make sure you're taking your medications regularly.
Consult your doctor about the effects of your medication on the baby.
Eat alot, especially if you are having trouble maitaining your weight.
Talk to your spouse about how they feel, make your decisions wisely.
I really wish that my wife and I knew that she was sick before we had kids. We would have gotten her treated first and enjoyed our youth a little more. Knowing us we still would have had children, but I think it would have taken us longer to pursue it. I love my children and I'm glad that things are looking up. We had a few close calls but we always pulled through. Some times life gives you a bad hand and you gotta deal with what you get. It's not impossible to get pregnant with thyroid disorders, but its not easy and in some cases it really might not be worth the consequenses that come with it. I wish any one who is reading this the best of luck and the best for your whole family.