OHSS Explained – The 411

baby - OHSS


There are many different regimens for prevention/reduction of OHSS because the condition is poorly understood even by many REI doctors. Case in point is the wife of a prominent REI that nearly died after her husband fluid restricted her to prevent OHSS. OHSS, at its root, is a cluster of symptoms that result from leaky capillaries in the ovarian follicles. After ovulation, even in natural cycles, new and temporary capillaries are made in response to LH/hCG. These capillaries invade the granulosa cells of the follicles, delivering cholesterol to these cells so that the granulosa cells can produce progesterone (which is made from cholesterol). These capillaries, made in haste, are leaky. The fluid portion of the blood leaks through the capillary wall but the cellular part of the blood stays in the capillary. This is not a big deal in a spontaneous cycle as there is only a single follicle in most cases. In typical cases of OHSS, there are many, many follicles and therefor a lot of leaky capillaries. The fluid that exudes from the capillaries accumulates in the abdominal cavity as ascites. In an IVF cycle this can occur at two different points. The first point is after hCg administration and the second point is when hCG levels start to rise after pregnancy has been established. In severe OHSS, the ascites can accumulate to the point that the abdominal cavity is so full of fluid that it interferes with the diaphragm’s ability to move and makes breathing labored (‘respiratory embarrassment’ in medical jargon). the pressure from the fluid also puts pressure on the stomach causing a sense of fullness and decreased appetite as well as pressure on the vessels perfusing the kidneys. To understand the rationale for my recommendations, you must first look at the principal symptoms of OHSS and their causes. One also has to keep in mind that OHSS is a self-limiting condition and will get better on its own with time in nearly every case. I will list the common symptoms in ascending order of seriousness. Please understand that only in very unusual or neglected cases do these things result serious threat to the patient’s health. OHSS is always a matter of temporizing treatment designed to reduce symptoms and buy time while the OHSS resolves on its own.

1. Decreased urine output. This is defined as less than 30 mL of urine per hour. It is caused by a combination of factors that lead to decreased renal perfusion. These factors include: decreased blood volume due to the leaking of fluid from the capillaries in the follicles to the abdominal space as ascites; increased intra-abdominal pressure due to tense ascites causing a.) decreased blood flow to the kidneys. b.) decreased fluid intake because the patient feels full; alterations in the renin-angiotensin system that controls salt balance. This is poorly understood and may be genetic.

2. Increased blood viscosity. This is the result of the fluid portion of the blood leaking through the capillaries leaving the cellular portion of the blood highly concentrated within the vascular system. This can put patient at risk for thrombus formation (blood clot).

3. Low sodium (hyponatremia). The combination of low sodium and low intravascular volume is somewhat of a paradox and is also accompanied by low potassium (hypokalemia). This is due possibly to the follicles functioning as faulty glomerulii (the glomerulus is the filtering apparatus of the kidney and usually retains sodium and potassium) as well as the alterations in the renin-angiotensin system which I alluded to above.

4. Ovarian enlargement and pain. This is due to the stretching of the capsule of the ovaries. This occurs as the ovaries increase in size due to the ‘lutienization’ that occurs in response to hCG. This is typically the most common symptom, occurring in moderate as well as severe OHSS, as well as the most bothersome symptom for patients.

My recommendations:

1. Drink at least two protein supplements per day each containing 30 grams of protein. Try to eat protein rich foods like meats and legumes. Rationale: the protein will serve two purposes. It will possibly help provide substrate so that the capillaries formed are more substantial and less leaky. Protein will also provide substrate for the production of albumin. Albumin is a component of blood that is integral in keeping the fluid part of the blood from leaking out of the vascular system. The albumin is too large to leak out of the capillaries and will (hopefully) provide oncotic pressure and keep more of the liquid part of the blood in the vascular system, thereby reducing ascites. Failure to get adequate nutrients will quickly lead to a reduction of albumin production and is part of the reason that patients often rapidly deteriorate with OHSS when the get tense ascites and lose their appetites.

2. Drink electrolyte balanced fluids rather than water. Gatorade or like electrolyte drinks will provide sodium and potassium, which is being lost in the ascitic fluid. Maintaining adequate hydration is key to maintaining adequate renal perfusion. When you are thirsty or notice dry mouth and lips, chug Gatorade. If you have concentrated urine or dry mucus membranes, you are not getting enough fluid, drink Gatorade until it improves. Coconut water is another popular electrolyte rich fluid but is not as good as Gatorade in my opinion.

3. Put extra salt on your food and eat salty snacks. See number 2 above. You need sodium and potassium. Low sodium and potassium contribute to the feeling of lethargy and decreased appetite that often accompany severe OHSS. You are losing sodium through the capillaries and need to replace it.

4. Stay off your feet as much as possible. Walking excessively results in increased ovarian pain and may also increase leaking from the new capillaries. Often the pain is most noticeable at night. Staying off your feet may also aid in the reabsorption of the ascitic fluid.

5. Take a baby aspirin per day. All of my patients are already doing this OHSS or not. The 81 mg of aspirin helps to prevent clotting of the concentrated blood. In certain severe cases, lovinox may be added to prevent thrombus formation.

6. Take narcotic pain medication as needed for pain. We usually prescribe Vicodin. You do not get extra credit for being a hero.

Things your doctor should keep in mind:

1. IV hydration can be provided as needed in an outpatient setting and should be provided liberally to maintain renal perfusion in patients having a hard time getting enough fluids in.

2. Ultrasound guided transvaginal paracentesis can be used in an outpatient setting to relieve tense ascites. This relieves respiratory embarrassment and improves renal perfusion through the reduction of intra-abdominal pressure.

In most severe cases, giving fluid and draining fluid in an out patient setting to maintain renal perfusion is usually all that is needed to temporize until the OHSS begins to resolve on its own.

For patients:
When you have you first day where you do not feel worse than the day before, you are usually about to begin improving.

Once you are on the mend, you will begin to notice a high rate of urine output as your body reabsorbs the ascites and get rid of it through your urine.

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