Strug publishes study exploring potential method to improve IVF


by Sumaira Hai

Michael Strug, a seventh-year DO-PhD student in the who recently completed his PhD in Pharmacology & Toxicology has published a study in the journal Human Reproduction that could lead to improved success in human in vitro fertilization (IVF).

Strug explained that women undergoing IVF treatment take fertility medications that help to stimulate production of many eggs. These eggs are surgically removed and then used for IVF. However, these medications alter the normal levels of hormones secreted by the ovaries, which changes the characteristics of the endometrium – the uterine lining.

In fact, the altered hormone levels cause the endometrium to mature during the normal menstrual cycle at a faster rate. These changes can make it harder for the fertilized embryo to implant into the uterus, thus making it difficult for a woman to get – and stay – pregnant.

Typically, human chorionic gonadotropin hormone, or hCG, is secreted by the embryo prior to implantation, which has many important functions including regulating ovarian hormone levels. However, Strug hypothesized that one of these functions of hCG is to maintain and regulate the uterine lining so it can become a hospitable environment for a growing fetus.

“I am really interested in the mechanisms that promote a uterus to accept an embryo and this study really stems off our work in determining the role of hCG in the non-human primate endometrium,” Strug said. “Other clinical studies have shown that the amount of hCG secreted by an embryo correlates with the success of embryo implantation and if hCG is provided prior to embryo transfer it can improve pregnancy rates.”

With the help of his advisor, Asgi Fazleabas, Professor and Associate Chair of Research in the Department of Obstetrics, Gynecology and Reproductive Biology, Strug tested his findings and found that infusing hCG at a specific time would restore the endometrium to its optimal state for embryo implantation.

He explained that he chose to study IVF egg donors because they are a fairly homogenous population of young, healthy women and are fertile.

“Part of our study required an endometrial biopsy and this cannot be performed on infertile women undergoing IVF, as it would disrupt the pregnancy,” Strug said.

The participants underwent the normal process to harvest eggs for IVF. However, after their eggs were retrieved, hCG was infused into the women’s uteri at the same point that an embryo would be transferred to the uterus in a patient undergoing an IVF protocol.

They then performed an endometrial biopsy two days later at the time right before the embryo would actually implant in the uterine lining.

Their results showed that the incorporating hCG corrected the negative effects of the increased hormone levels from stimulating egg production, making the uterus fit for a growing fetus.

They also saw increased levels of other pathways necessary for embryo implantation, which were positively affected in their non-human primate model.

Following the publication Strug continues to study hCG. He hopes to continue his research and study the mechanisms by which hCG infusion might increase IVF success rates in infertile patients.