Treated for thyroid cancer, having unusual bleeding


I am a 21-year old who is getting married 2 weeks from today! My fiance and I are planning on using NFP for the first 8 months because I’m not supposed to get pregnant until then because I’ve been treated for thyroid cancer with radioactive iodine. I’ve been charting for the past 8 cycles, and everything has more or less been fine until this past cycle. This cycle I have been bleeding for 13 days. There was only about 6 days of normal bleeding, and then it’s just been a little, usually mixed in with mucus. I also have felt unusual cramping every now and then for all 13 days. I also began taking an antibiotic right before I began my period this month. I’m not sure if I should make an emergency appt. with my gynecologist before the wedding, or if it’s not something to be too worried about. Could the antibiotic have messed things up? Could it be stress? (I’m also in the process of finishing my last semester of college.)


Congratulations to you and your fiance on your upcoming wedding. You certainly are under a lot of UNUSUAL STRESS! You are finishing college and planning a wedding. That alone could cause cycle irregularity, and sometimes unusual bleeding. You don’t say why you started an antibiotic before your period. The bacterial infection which required antibiotic therapy would be an additional stressor.

However, your thyroid cancer and treatment, which includes surgery and radioactive iodine, are certainly the most significant stressors. The thyroid is an important gland in the regulation of fertility. The radioactive iodine destroys the cancer. However, it also destroys the healthy thyroid tissue which produces the thyroid hormones. Supression of the gland and the hormones it produces is the treatment for the cancer. However, your doctor, preferably an endocrinologist, will need to prescribe an oral thyroid replacement hormone. It is important to see your doctor on a regular basis in order to monitor the thyroid hormone levels as well as the effectiveness of the treatment for the cancer. The correct hormone level is necessary for regular cycles, and your overall health. Your current unusual bleeding is probably related to your recent treatment and the suppressed hormone levels.

You should see your gynecologist. Be sure he/she knows about your recent thyroid cancer treatment. He can rule out an additional gynecologic condition. Also make an appointment to see your NFP teacher or practitioner. She can help you during this time of stress and unusual bleeding. If you have been learning NFP without a teacher or practitioner you should get a referral from CANFP for a certified teacher/practitioner who can help you navigate through this time of hormone imbalance.

It is very important not to become pregnant, obviously because the radioactive iodine can cause miscarriage or fetal abnormalities. However, the thyroid hormone levels also need to be in the normal range in order to have regular cycles, and be able to achieve and maintain a healthy pregnancy when you and your husband are ready to start your family.

I hope this information answers your questions. Best wishes to you and your fiance. May God Bless you both with health and happiness.

Pat Poindexter

Answered By:

Pat Poindexter RN, CFCP, FCE
Pat Poindexter, RN, taught the Creighton Model of FertilityCare in the Los Angeles region, now retired

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