Ovarian Hyperstimulation syndrome (OHSS) and IVF

China is finally ending its decades-long one child policy. One child policy was introduced in 1979. For those who were in their fertility prime age during the policy’s implementation, it may be too late to try for a second child now. The renewed policy allows a second child as on January 2016. Many Chinese say that when the body (women ovarian reserve) allows for a second child, the system does not, and when the system allows for a second child, the body does not. Ever since the second child policy implementation, fertility demands in China has risen. During my recent travel to China, I’ve noticed that many Chinese hope to produce more eggs via in-vitro fertilization (IVF) so that more embryos are available for genetic tests. However, when too many eggs are produced via IVF, it increases the risks of Ovarian Hyperstimulation Syndrome (OHSS).

What is OHSS ?

OHSS is an excessive response to taking fertility medicines (especially injectable gonadotropins) used to make eggs grow in IVF or any assisted reproductive treatment. Royal College Obstetricians & Gynecologists Green-top Guideline no. 5 proposed classification of severity of OHSS classified as mild, moderate, severe and critical. Mild OHSS is common in women having IVF treatment; one out of three women develops mild OHSS. These symptoms may include mild abdominal bloating, nausea and weight gain due to fluid. Women with severe OHSS usually have vomiting and cannot keep down liquids. There is discomfort from abdominal distension. They can develop difficulty in breathing or blood clotting in deep veins in legs.

Who is at risk?

The risk is higher in young women who have Polycystic Ovaries Syndrome (PCOS), had OHSS history, got pregnant in the same IVF cycle (fresh embryo transfer) as they get their symptoms, particularly if this is a multiple pregnancy. Large number of follicles during ovarian stimulation and high level of estradiol before a HCG trigger injection for final egg maturation or ovulation in assisted reproductive treatment will also increase the risk of OHSS. If you are a young egg donour, your OHSS risk is same as those who are undergoing IVF.

How to reduce the risk of OHSS?

There are many ways to reduce the risk of OHSS. Many patients are trying to get more eggs possible in IVF. However, the balance between risks of OHSS and number of eggs need to be considered. Your fertility doctor will decide the ideal dosage for you based on your age, ovarian reserve and previous stimulation history. Follicles growth monitoring, and control or reduce of ovarian stimulation medications, may reduce the risk of OHSS. Many studies have suggested that the antagonist protocol stimulation and agonist trigger in IVF can reduce the risk of OHSS. You can speak to your doctor to know if you’re suitable for this protocol. Your fertility doctor may suggest you to freeze all your embryos if you are at risk of OHSS. If you have conceived from fertility treatment, this will increase your risk of OHSS, especially if it's a multiple pregnancy. However, your doctor will monitor you thoroughly throughout the pregnancy.

When should I call for help?

Call for help if you have below symptoms of OHSS:

- abdomen bloated

- shortness of breath

- nausea or vomiting

- difficulty in tolerating orally

- reduced urine output

What is the treatment for OHSS?

There are no treatments that can reverse OHSS. Usually, it will get better over time. Your OHSS symptoms usually will resolve by itself within two weeks, unless pregnancy occurs. The symptoms will continue for another 2-3 weeks or more after a positive pregnancy test, and gradually go away without affecting the rest of your pregnancy. Based on your OHSS severity, your doctor may give treatment and, discharge or admit you for hospitalization if symptoms get worse. At the hospital, abdominal girth monitoring, weight, intake and output monitoring, blood tests or scans will be carried out. Your doctor will put you on drips if you are losing too much fluid from OHSS. If there is accumulation of fluid in the abdominal cavities and abdominal swelling (ascites), procedure to drain out the fluid may be needed. A medicine called Cabergoline can be given to reduce the ascites.

What are the complications of OHSS?

OHSS complications are rarely severe. Patient may be dehydrated due to fluid loss to other body cavities like abdomen or lungs. This can lead to increased pressure in the cavity due to too much fluid accumulation. It can cause blood-clotting in the blood vessels, and the clots can travel to the lungs or other important organs. This is potentially life threatening. These complications can be avoided by seeking medical help during early OHSS symptoms.

In summary, OHSS is common after ovulation induction or ovarian stimulation for assisted reproductive treatment, particularly in IVF. Patients who experience signs and symptoms of OHSS should seek medical help from a fertility doctor as soon as possible. Standard pelvic examination should be avoided to prevent cysts or ovaries burst after pressure.

There are many ways to reduce risk and complications of OHSS by modifying your assisted reproductive treatment protocols or giving some medications. Knowing when to call for medical help while having OHSS symptoms is important in its prevention. Talk to your doctor if you have concerns about OHSS.

Written by:

Ms Tan Mei Yuen has completed her diploma in nursing from SEGi university. Ms Tan then further pursued her bachelor of nursing science with honours in Open University Malaysia and majoring in Paediatric nursing, renal nursing and intensive care nursing. 7 out of 500 graduates have passed their nursing degree with distinction in nursing school, she is 1 of the 7.

She became a registered nurse in Tropicana Medical Centre(TMC) since year 2011. Since 2011, she was posted in Tropicana Medical Centre, Fertility Centre. Ms Tan obtained her Reproductive Endocrinology and Infertility(REI) nursing certification with flying colours from American Society of Reproductive Medicine(ASRM) on year 2014. Ms Tan is currently a Senior Registered Nurse in charged in TMC fertility centre.

She is actively involved in many quality initiatives for the centre and organising varies fertility public forum to create fertility awareness for Malaysia society. Her biggest wish is to create awareness to young married couple to trying conceive as early as possible because she believe any delay in trying to conceive will decrease their chances in conceiving later, with more expensive price.

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