Natural killing cells are vital in protecting your body from infection but large numbers can kill your foetus…

Going through a miscarriage can be a physically and emotionally challenging experience for any couple. And if the miscarriage follows a long struggle with infertility or if you’ve had recurrent miscarriages — the loss can be especially devastating.

The truth is, more than 50 per cent of recurrent miscarriages happen with no identifiable cause, notes Dr Lim Min Yu, ob-gyn and clinical director at the Advanced Centre for Reproductive Medicine at Gleneagles Hospital.

Ob-gyn Dr Peter Chew lists several causes of recurrent miscarriages:

* Genetic and hormonal problems.

* Infections and thrombophilic (blood-clotting) defects.

* Uterine issues and cervical weakness.

* Environmental causes.

* Lifestyle problems.

SmartParents expert and consultant ob-gyn at Gleneagles Hospital, Dr Christopher Chong notes that the presence of Natural Killing cells (NK cells) in the body is another “fairly new and not well understood” cause of recurrent miscarriages.

What are NK cells?

NK cells are a type of white blood cell present in your immune system and can be found in various parts of the body, including the bloodstream and even your uterine wall. Dr Lim explains that these cells protect the body against viruses and cancer.

“However, if the number of these NK cells is too high, or they become more aggressive than usual, they may attack rather than protect the pregnancy and cause a miscarriage.”

If you suffer from an inflammation or infection in the lining of the womb — called endometritis — the increased numbers of NK cells can prevent the embryo from implanting, says Dr Chong. Dr Lim adds that studies have shown women who’ve had recurrent miscarriages do have an increased level of uterine NK cells in their womb lining.

NK cells, produced during your pregnancy to protect the embryo and ensure its development over time, are usually harmless, Dr Chew states. “However, if the number of these NK cells is too high, or they become more aggressive than usual, they may attack rather than protect the pregnancy and cause a miscarriage.”

The good news is NK cells are a very rare cause of recurrent miscarriages, Dr Lim notes. “In a normal pregnancy, the uterine NK cells are the highest during the first trimester before decreasing in numbers in the second and third trimesters.” Dr Chew adds that the role of NK cells in causing a miscarriage is still considered to be controversial.

What should you do?

Ask your gynae to run a blood test to check for the CD56 immune marker or a biopsy can be done on your womb lining to identify the presence of NK cells, Dr Chong advises.

Once diagnosed, Dr Lim says intravenous immunoglobulin (IVIG) and steroids will be prescribed to treat your condition. However, Dr Lim warns, “It is important to note that at present, there is no proven effective treatment, and that more research into this area is required.”

While this may sound discouraging, Dr Chong reassures you that even after three consecutive miscarriages, “the chance of a normal pregnancy is in the region of 70 per cent”.

What is more important is that you seek a medical professional’s help as early as possible to explore the possible causes, then get it under control before you try for (another) baby.

“See your gynae early, so that you can start on a course of medication before trying for your next child in the best possible health,” Dr Chong advises.

Photo: iStock

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