What happens in the body after an embryo transfer: Embryo implantation
For couples undergoing IVF treatment, an embryo transfer is like the finish line - after ovarian stimulation for the release of healthy eggs, the eggs are very carefully collected, fertilised 'in vitro', and introduced into the uterine cavity after laboratory cultivation. How does the embryo implant in the uterus?
Once the embryos are introduced into the uterus, it usually takes about 10 days for hCG levels to be high enough to be detected by a pregnancy test. However, many women have no idea what goes on inside their body during this 'waiting' period. We can't look inside, so let's at least describe what goes on after a successful embryo transfer.
Embryo implantation day by day
Day 1: The embryo as a hatching blastocyst (it reaches this state after five days of cultivation in the laboratory) begins to hatch and its cells continue to divide.
Day 2: The blastocyst continues to hatch and once it's hatched ('out of the shell') it begins to attach to the uterine lining - this step is absolutely crucial for a successful pregnancy.
Day 3: The blastocyst bores deeper into the uterine lining and implantation (embryo nesting) begins. Because the uterine lining is richly perfused, spotting or light bleeding may occur at this time. If you experience this, don't worry - this isn't a bad sign. About 20-40% of women experience this in early pregnancy regardless of the method of conception.
Day 4: At this point, the blastocyst is so deep that it connects to the blood supply in the endometrium (uterine lining). Some women may experience heavier bleeding at this time, but you don't need to worry if you don't experience any spotting or bleeding at all.
Day 5: The embryo implantation, or nesting, is now complete, and the embryo continues to develop allong with cells that will eventually turn into the placenta.
Day 6: Placenta cells release hCG, which is the hormone detected by pregnancy tests. This hormone triggers increased progesterone production in the first trimester, which ensures that the uterine lining grows and keeps the foetus growing.
Day 7: The continuing development of the placenta releases even higher levels of hCG into the bloodstream.
How can you improve your chances of successful embryo implantation?
The days following an embryo transfer are full of hope as well as worrying. For many women, the two-week wait to find out if the embryo has 'nested' seems to last forever, and it's only natural that they want to do everything they can to make sure it works. However, the belief that you should stay in bed for a few days or lie in strange positions is just a myth.
Although you shouldn't overdo it after an embryo transfer, this just means you should avoid extremes: forget about excessive exercise (instead, go for a walk), don't lift anything heavy and don't take hot baths - this could damage the development of the embryo. Until the 10th day after the embryo transfer, you should shower with water that is 'just right' and focus on activities that you enjoy - only then will you avoid excessive self-observation and help the waiting period go faster.
