Understanding What Makes The Best Uterus For Pregnancy

The lining of the uterus needs to be ready to have an embryo implant. What really makes the best uterus for pregnancy has been a topic of hot research. The uterus has the myometrium, or muscle layer, and an inner lining layer called the endometrium. Gynogab has pointed out that the hormone estrogen and the fact that it is necessary, at least, for that lining to be prepared. And we've discussed that the lining can be disrupted by polyps, endometriosis, lack of proper hormone stimulation, and fibroids, and that might not make the best environment for uterine implantation or more accurately the best place for egg implantation to occur . And we've discussed that in order to know if a pregnancy has gotten established it's important to watch hormone levels rise, but for most that just means watching the level of placental hormones. 

But there is so much more to having a healthy lining, and a whole section of the September 2011 issue of Fertility and Sterility, the journal of the American Society for Reproductive Medicine, has been devoted to discussing just this topic. The experts have been interested in this topic for many years. One of the founders of the birth control pill, Dr. Rock, did work with his partner Dr. Hertig in 1956 that really paved the way for the concept that the best uterus is one with a very healthy lining. To really understand the uterus we have to look at what levels the estrogen exposure occurs in, we have to look at the amount of progesterone, we have found presence of a type of tissue structure called pinopodes, or as some call them uterodomes, that have to be healthy, and now we have discovered a whole set of other phenomenon like how often the uterus contracts and which genes that get turned on and off to create the special molecules make this the best uterus for pregnancy! It turns out that monthly cycles, approximately 28 day cycles, with about 14 days of the estrogen time is a great system for the average patient with no fertility problems. But some of the newest information is that experts don't have a specific amount of time that estrogen should be given, but in many it's longer than the 14 days and some studies show a medically induced longer period of estrogen: full 5 weeks of estrogen may be best, as the lining has to have the right kind of receptors so that it is most receptive to the estrogen treatment. This is most true of women who have reasons for the lining to be less responsive: such as women who were on long term estrogen. Infertility due to poor implantation and early pregnancy loss is common. After all the uterus and placenta have to connect through at lease 100 blood vessels, known as spiral arteries, that will be the blood supply for the placenta for the whole pregnancy.

We still think that endometriosis is the most common cause of infertility, and some of these women may have particular problems with these lining structures and the health of the uterus at the time of implantation. The egg literally needs to be glued to the lining with "stick-um" proteins, sugar coated proteins called glyoproteins, and there is a whole group of these. These stick-um proteins are called integrins. Some of the newest tests specialists are using to determine if the lining is ready is to actually look for these integrin levels, but other tests, like testing for the gene products that encode for these molecules are being evaluated as well. It may also be that these proteins have something to do with whether uterine scaring takes place after a surgery, infection or D and C. This scaring is called uterine synechiea. So if you skipped over some of your biochemistry in high school when they were talking 'the birds and the bees' you'll be glad to know, we've rewritten all that stuff since then. But the news is, that it's a whole lot more complex and our experts are still working hard for us to determine how to eliminate this important cause of infertility!