age: 38, had etopic pregnancy in 2011, did 3 cycles of IUI but not succeeded. IVF: first cycle with embro transfer done 10 days ago(on 21 Feb 2014) this morning 3am felt sudden cold(so cold that I could not stop shivering which lasted around 5-10mins). After the cold subsided, felt severe cramps at lower admen for about 3mins. after the cramps subsided, I still feel cold and shivered sightly throughout the night. Also, I sweat a lot. I have been having the cold shivers with sweat two days before every menstrual period comes since last year(also during the time I did the IUI). Before I started the IVF procedure, I have told my doctor but he did not show much concern that it will affect the IVF.