Tatjana Motrenko Simic, Human Reproduction Center, Budva, Montenegro
When ovarian stimulation starts, it is essential to monitor ovarian response and follicular growth in order to adjust gonadotropin dosage and determine time when follicles reach proper size for stop injection. Usually, we perform ultrasound monitoring 6-7 days after stimulation start and record size and number of follicles growing, adjusting gonadotropin dosage if it is needed. Patients are scheduled to be seen every other day until follicles reach proper size for triggering ovulation. This size differ for variety of protocols, but it is accepted for long one to be 20 mm, and for antagonist protocol when 3 leading follicles reach size 17-18 mm. But we have to have in mind there is small proportion of patients reacting differently form majority, and need more stimulation and even bigger size of follicles in order to get mature cells. Those patients are very often one coming with good antral follicle reserve and small number of oocytes retrieved in previous IVF cycle. If there was no previous IVF attempt, unfortunately there is no way to know this in advance. Also it is important to check does patient received properly stop injection, or receive at all, especially in case of first IVF attempt, because if it is not case we will not obtain oocytes at all, or very few oocytes in case of lower bHCG concentration. This could be avoided by asking patients to give blood sample for bHCG measuring in lab next morning after stop injection, so in case of not receiving, we will see almost unmeasurable bHCG concentration. Analyzing cases of so called empty follicles syndrome, 95% of those patients didn’t received properly stop injection or got is in a wrong way so bHCG concentrations were very low. Still you can rescue cycles by repeating stop injection and rescheduling pick up, 34 to 36 hours after.
To prepare equipment properly we have to take care about sterility having in mind the needle will be in used to enter abdominal cavity and one of complication of procedure could be infection and tube-ovarian abscess. Probe is covered by sterile glow or better with sterilized cover designed in different size depending of operators preference and can cover probe and part of probe cable too. Needle guide could be reusable or disposable, even in case of other cost is much higher. There is variety of aspiration needles at market and choice depend of operator preferences. Still, it is important to choose needle with good visibility under ultrasound, rigid enough to follow line of aspiration without bending, and tubing system made out of high quality plastic, to avoid curling and stopping fluid to flow in case of needle rotation. Before we start with follicles aspiration it is recommended to wash needle with media, what will prepare aspiration system for oocytes and check aspiration pump before we start. Aspiration pump pressure should be around 120 up to 140 mm Hg, avoiding to high pressure to distort oocytes. Also, tubes for collecting follicular fluid should be kept in warm holder adjust of 37°C degree, since it is known cooling of oocytes can cause permanent genetic damage and increase aneuploidy, harming whole process and further success.
After preparing all and checking equipment we can start procedure. What we will choose for vagina washing depend of availability and our preference, from saline solution to some nontoxic disinfectant.
If this is possible probe should be placed to reach as much as we can with one puncture for ovary, what is sometimes difficult in case of higher number of oocytes or ovaries out of usual position. Technique for aspiration differs, some authors claim that rotating of needle will provide more oocyte, some other do not see the difference. But it is important to keep needle the middle of follicles in order to obtain all fluid inside; otherwise collapsed follicles walls will obstruct fluid flow and aspiration. Keep in mind probe direction and reach other follicles by moving forward and backward needle, holding firm the probe and do change of direction only when needle is on the proximal edge of ovary, but without rotation, since tip of needle could be invisible and lost on screen, causing damage to surrounding tissue or blood vessels or even organs. One of complication a part of infection is bleeding. Usually some small amount of bleeding came from fornixes, and could be stopped by simple pressure by gaze hold in instruments. But in case of bigger bleeding not stopping after pressure, even few stiches are needed in rare cases. Or vaginal tamponade can be performed with close follow up of patients. A part of dominant follicles it is wise to aspirate even smaller ones knowing there is small chance that cell will be picked up, but for sure this will reduce ovarian size.
When we aspirate all follicles needle should be washed with media – we have to aspirate at least several medium milliliters to collect cells kept in aspiration system.
For beginners it is wise to start with ultrasound guided cyst aspiration just to become familiar with transvaginal puncturing and all tips and tricks related to this relatively simple procedure.