Infertility/Fertility/Medicated FET cycle


Dear Dr. Ramirez,

I would like to seek your advice on my upcoming FET.   On day 4 of my cycle, I am to start premarin 0.625mg 2 tablets 3 times a day.  On day 12 transvaginal ultrasound will be done to see the thickness of my endometrium lining.   If the lining is acceptable, then I will start progesterone.  

My question is how accurate is timing of premarin?  Would it make a significant difference if I start premarin on Day 5 instead of day 4?    I start getting pink discharge after 6pm today (February 13).  It's pretty late in the day so I''m not sure if today counts as day 1...

Thank you.

Hello Susan from Hong Kong,

In an FET cycle, estrogen is used to grow the uterine lining.  Once the lining is thick enough, then progesterone is added to convert the lining microscopically into the form that will allow the embryo to implant.  That is the part where the timing is critical, that is, when you start the progesterone.  The timing for the estrogen use is variable and can go long or short.  You only need to wait for the lining to develop before starting the progesterone.  

Any type of estrogen is okay for this purpose.  I have heard of some clinics using oral estrogen but in general, the patch or vaginal forms are the most effective.  Also the dosage of the estrogen is important because without adequate estrogen the lining will not get thick enough.

Good Luck,

Dr. Edward J. Ramirez, M.D., FACOG
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program

Monterey, California, U.S.A.

for additional information check out my blog at check me out on twitter with me at @montereybayivf and facebook @montereybayivf.  Skype and internet comprehensive consultations now available via my website for those who want a more extensive evaluation that this site can accommodate.  I also now provide an Email Concierge Advisory Service with a 1 year subscription for patients that want easy access to me to answer questions along their journey (women's health, infertility, pregnancy).  Contact me at if you are interested in continuous access to me.


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Edward Joseph Ramirez, MD, FACOG


I am a specialist in infertility and advanced gynecological care. I can answer questions about infertility, gynecology related ills, menopause...virtually anything that affects women's health. PLEASE tell me where you are writing from as I am always interested.


I have been practicing as an Ob/Gyn and Infertility Specialist for over 23 years. Gynecology, advanced laparoscopic surgery, basic infertility, IUI's, IVF, reproductive surgery, and ovulation induction are all areas of my expertise. I am Board Certified. I have been doing In Vitro Fertilization in my clinic for 19 years.

American College of OB/GYN, American Board of Obstetrics and Gynecology, American Society of Reproductive Medicine, California Medical Association, American Association of Gynecologic Laparoscopists, Fellow of The American College of Obstetricians & Gynecologists

American Journal of Obstetrics and Gynecology, Wall Street Journal, Monterey Herald, SERMO, Women's Health and Fertility Blog

Medical Degree from Stanford University, Residency at Tripler Army Medical Center, Reproductive Training at Pacific Fertility Center, San Francisco

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