Does endometrial thickness matter?

This is one of a series of news items from abstracts of studies presented at the Annual Meeting of the American Society for Reproductive Medicine as complied by Dr. David Meldrum, Scientific Director of Reproductive Partners. We appreciate the enormous amount of work it takes to compile and comment on these abstracts.


Apparently it does, at  least according to these poster presentations

Pregnancy outcome in 9550 IVF pregnancies was evaluated according to endometrial thickness. With thickness < 5 mm, the risk ratios for first trimester and second trimester losses and preterm delivery were 1.5, 2.8, and 1.4, respectively. Birth weights were also reduced. Stillbirth was increased 4-fold. Women with endometrial thicknesses less than 5 mm should be advised on the risks of proceeding with hCG and that any resulting pregnancy should be treated as high risk. In fresh IVF cycles, freezing all embryos using vitrification should be considered with maximum efforts to achieve an endometrial thickness of over 5 and preferably over 7 in the frozen (FET) cycle. These outcomes may or may not pertain to non-IVF pregnancies.

But in another poster presentation, that issue was addressed and the outcome was similar. In a cohort of 2090 women receiving clomiphene with gonadttropins for IUI, multiple logistic regression analysis showed a correlation of endometrial thickness and pregnancy. Clinical pregnancy rates varied from 9.3% with endometrium under 5 mm to 19.6% with endometrium > or = 10 mm. The greatest impact was observed under 7 mm. Measurement of endometrial thickness would be helpful in clomiphene cycles and estrogen could be considered for 5 days following clomiphene for those women with a thin endometrium. An alternative would be to change the protocol to gonadotropins without clomiphene.

So in this instance, size does matter.