This review highlights the ‘gap’ in knowledge regarding the contribution of thyroid dysfunction in reproduction. Thyroid dysfunction, which is quite prevalent in the population affects many organs including the male and female gonads, interferes with human reproductive physiology, reduces the likelihood of pregnancy and adversely affects pregnancy outcome, thus becoming relevant in the algorithm of reproductive dysfunction.
Although menstrual irregularities are common, ovulation and conception can still occur in hypothyroidism, where thyroxine treatment restores a normal menstrual pattern and reverses hormonal changes. Subclinical hypothyroidism may be associated with ovulatory dysfunction and adverse pregnancy outcome. Thyroid autoimmunity increases the miscarriage rate, and thyroxine treatment does not seem to protect. Menstrual disturbances, frequent in thyrotoxicosis are restored following treatment. In males, thyrotoxicosis has a significant but reversible effect on sperm motility. Although radioactive Iodine (I131) in ablation doses may transiently affect the gonads, it does not decrease fertility or increase genetic malformation rate in the offspring.
Awareness of the thyroid status in the infertile couple is crucial, because of its significant, frequent and often reversible or preventable effect on infertility. Many aspects of the role of thyroid disorders however in infertility need further research.
aPedieos IVF Center, Cyprus
bPediatric Endocrine Unit, Makarios Hospital, Cyprus
cAlithias Endocrinology Infertility and Diabetes Center, Nicosia, Cyprus
Correspondence to Krinos Trokoudes MD, Pedieos IVF Center, 8 Karaoli Street, suite 201, Nicosia 1095, Cyprus Tel: +357 22 670850; fax: +357 22 671892; e-mail: firstname.lastname@example.org