The Role of Progesterone

Progesterone’s one function is preparing the endometrium to receive an implanted embryo. If implantation does not occur, estrogen and progesterone levels drop, the endometrium breaks down, and menstruation occurs. If a pregnancy occurs, progesterone is produced in the placenta, and levels remain elevated throughout the pregnancy. The combination of high estrogen and progesterone levels suppress further ovulation during pregnancy. Progesterone also encourages the growth of milk-producing glands in the breasts during pregnancy.


High Progesterone on “Trigger Day” of IVF Cycle

The hCG hormone injection given to a female in vitro fertilization (IVF) patient 36 hours before egg retrieval to encourage ovulation of mature eggs, takes place on “trigger day” during an IVF cycle. High progesterone levels in an IVF cycle on the day of trigger are associated with diminished implantation rates and live birth rates, regardless of ovarian reserve. Progesterone prepares the endometrium for accepting an embryo for implantation, but a high level of progesterone (too soon), makes the endometrium significantly more advanced, causing desynchronization between the embryo and endometrium. When the uterus is no longer optimally receptive for an embryo that is ready to implant, a failed IVF cycle will likely result. (Dr. Liu, Reproductive Biomedicine, 2015).


An analysis of progesterone levels and early miscarriage rates for fresh IVF cycles from 2013-2016 at Carolina Conceptions was conducted. When progesterone is higher than 1.6 on the day of trigger, the early miscarriage rate is significantly higher (42.9%) than for patients who had a level below 1.6 (early miscarriage rate 18.8%).


For this reason, a patient with a progesterone level higher than 1.6 during a fresh IVF cycle, will be converted to a “freeze all” status– meaning the embryos will be frozen, and we will help the patient plan for a future frozen embryo transfer (FET) after her progesterone level has returned to a normal range.


Are Pregnancy Rates Lower for Frozen Embryo Transfer Cycles?

If your IVF cycle is converted to a “freeze all” status, our pregnancy rates for frozen cycle transfers are excellent, and in some cases even stronger than fresh ivf transfers (check out last month’s blog article from CC Lab Director, Dr. Sung Tae Kim –  summarizing data from a recent study completed at Carolina Conceptions suggesting frozen embryo transfers increase pregnancy rates in women age 35 years and older).



The table below displays similar pregnancy rates from our 2016 IVF patients

for fresh (69.5%) & frozen (60.4%) embryo transfers. pregnancy rates


The chart below shows IVF pregnancy rates for Carolina Conceptions through July 2017.

 Read more about how to interpret IVF success rates for fertility clinics on our website,

or watch Dr. Park’s video.

Carolina Conceptions pregnancy rates












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