Hello, and I hope I can help you today. Letrozole is a strong fertility medication that can produce ovulation in women who normally do not ovulate, such as women with PCOS. The Ovidac injection just induces you to ovulate at the correct time in your cycle to correspond usually with a timed insemination, either by intercourse, or by IUI. The fertility medication itself does not cause any risk to the baby if you do conceive, because the medications only affect your ovulation and ability to conceive. However, fertility medications such as Letrozole can produce high order multiple gestations (triplets and above) in women with PCOS because PCOS is a disease where women have many immature eggs waiting to be released. If you successfully conceive only one baby, your pregnancy is no more a risk than any other obese woman. You will have a higher risk of diabetes and high blood pressure during your pregnancy, and they should be tested for and monitored carefully, but with proper prenatal care women with PCOS and obesity can have successful pregnancies. So in summary, the fertility medications that you have been treated with really only increase the risk of conceiving multiple babies at the same time. The medications do not cause birth defects and are out of your system by the time you actually get pregnant. However, unless you have already tried milder ovulation induction medications (not injections) that failed in the past, I caution against the use of Letrozole as women with PCOS frequently conceive multiple eggs at the same time and twins or even higher order multiple pregnancies are possible. I hope I was able to adequately answer your question today, and I wish you the best in conceiving a healthy pregnancy. Best wishes, Dr. Brown