Immune cells vital for maintaining early pregnancy

SYDNEY - White blood cells (WBCs) help in maintaining early pregnancies and may explain why some women are infertile, and why some pregnancies end in miscarriage, says a new study.

Alison Care from the University of Adelaide (U-A) has examined the role of immune cells known as macrophages or WBCs within the ovary, which are found in abundance around developing eggs and in hormone-producing structures within the ovary.

Her research, conducted in mice, shows that when these cells are depleted there is a significant reduction in the amount of progesterone, a hormone the ovary produces. Progesterone is essential for the maintenance of early pregnancy.

“We know that the ovary requires a vascular network in order to deliver the high levels of progesterone the body requires to maintain early pregnancy. The formation of this network occurs very quickly following ovulation, and macrophages may be involved in establishing that blood supply,” Care says.

“It appears that the ovary has its own specialist pathway to achieve this, and that macrophages have an essential role in building the blood supply that we hadn’t previously appreciated,” a U-A release said.

“This research identifies immune system cells as critical determinants of normal ovarian activity and the maintenance of early pregnancy. This might be a key to help prevent early pregnancy loss, such as recurrent miscarriage.”

Care says a number of factors - such as smoking, obesity, poor nutrition and stress - could all alter the way macrophages behave and may provide reasons for infertility or miscarriage in some women.