I dont agree with the menstrual abnormalities mentioned by you. According to Harrison 18 ed (pg 2920 & pg 2923) "Women frequently experience oligomenorrhea or amenorrhea (in hyperthyroidism)".Ya. Hypo causes oligomenorrhoea and hyper causes menorrhagia. Also note that hypo cause diastolic and hyper causes systolic HTN
hmmmm, is it right that prolactin inhibit secretion of FSH and LH?Im not sure if this is the exact mechanism- but this is how it was explained to me :
In hypOthyroidism-- you have decreased t3 and decreased t4. This causes TRH to be INCREASED ( trh from hypothalmus)--> We know that TRH stimulates PROLACTIN and hyperprolactinemia cuases decreased LH/FSH --> amenorrhea .**
HypERthyroidism can also cause amenorrhea. The mechanism behind this involves SHBG regulation ( produced in liver). So, hyperthyroidism leads to Increased production of SHBG-- this leads to decreased amount of free estrogen --> decreased chances that you will have an LH peak and therefore AMENORRHEA.
**My confusion now lies in the fact that MTB 2 pg 112 says " hypothryoidism is characterized by almost all bodily processes being slowed down except menstural flow which is INCREASED".
I hope my mechanism hasnt confused anyone. If this is incorrect, please let me know and ill take it down .. dont want to confuse others.