Medicated vs. Natural Cycles as a Gestational Carrier
By Michelle Avery
Over the course of decades of science and research surrounding IVF, the topic of medicated vs. natural cycles has become one of debate and discussion, particularly in recent years. Every doctor aims for each patient to have success with as few embryo transfers as possible.
Deciding between a medicated or natural cycle can be a personal choice or one recommended by your clinic. In either regard, our aim as a surrogacy agency is to help surrogates better understand the basics of both processes so they can make an informed decision.
Medicated Cycle General Process:
A medicated IVF cycle involves controlling all aspects of the cycle from the beginning, including your cycles timing. This allows for planning of medication start dates (often referred to as a med calendar), lining checks, transfers etc. Some clinics will start this process a month or two before a planned embryo transfer. If you live far away from your treating clinic, these types of cycles can be easiest to manage.
Generally, you would start a medication to supress your ovulation when your cycle starts and then have a lining check around the 10th day of your cycle. The lining check is an internal ultrasound to examine the thickness and pattern of the uterus.
Once your lining meets your clinics requirements, they will schedule your embryo transfer. With a medicated cycle, you will have more flexibility when planning a transfer and do not need to transfer right on day 15 or 16. You can transfer up to about day 20-22 (again-clinic dependent), the only requirement is that you have started your intake of progesterone either by needle, suppository or oral medication, and have taken it for 5 days prior to the transfer day. (*note* some women may require a test to determine their individual receptivity, which could lead to 6 or 7 days of progesterone prior to transfer.)
You will continue the progesterone, estrogen and any other medications until either weeks 9-12 gestation are reached or it has been determined that the embryo did not implant and grow. Often there are other medications added to protocols, but these are all clinic and doctor dependent.
Natural Cycle General Process:
Natural cycles work with the bodies natural reproductive cycle and require less medication. However, they often require more monitoring. You would not take medications to supress your regular ovulation cycle, as you would a medicated cycle. Instead you will start tracking your ovulation around Day 9 of your cycle. It is imperative during a natural cycle that you abstain from any sexual activity that could result in the fertilization of your own egg.
The reason for ovulation testing is so the doctor can plan your embryo transfer around your natural ovulation when the body will release the Corpus Luteum. The purpose of Corpus Luteum is to make your uterus a healthier place for a fetus to grow. It is a temporary organ that appears every menstrual cycle and disappears if fertilization does not occur. It also produces the hormone progesterone during early pregnancy.
Ovulation is generally tracked at home with over-the-counter tests available at your home pharmacy, starting around day 9. Once your ovulation is detected, your clinic may require confirmation with blood work and ultrasound, and potentially an HCG trigger shot, which will force ovulation 36-48 hours after it is administered. Your clinic may have you start progesterone in preparation for the embryo transfer, but every doctor has different protocols that they use for success.
Once you have entered the ovulation phase of your cycle, the transfer must occur on a very specific timeline. The introduction of the embryo into the uterus during the ‘perfect’ hormone and fertility phase for natural reproduction is the goal.
The Corpus Luteum will provide progesterone to the growing fetus until the placenta takes over hormone production, but there are many clinics that will prescribe additional progesterone to ensure that the embryo has a sufficient supply to develop.
There are many times that ovulation doesn’t occur when we expect it, which can lead to additional blood work and ultrasounds, and you may find yourself in a time crunch to book diagnostic tests for monitoring the cycle.
Although many doctors are on board to try natural cycles, their goal is always to achieve pregnancy as quick as possible and they will make recommendations on which route they think is best based on their knowledge and expertise.
Learn more about surrogacy by connecting directly with our team.
