Monitoring IVF treatment cycle
There are several aims when monitoring the treatment cycle. These include: checking the development of follicles and lining of the uterus, to adjust the dose of the drugs if necessary and to time the hCG injection. Each patient is different, so the ovarian response varies between patients both in the number of follicles produced and the speed at which they mature. On average, you need to attend the clinic for two or three visits and occasionally more to see how well you have responded to the injection and adjust the dose of the injections accordingly.
The development of the follicles is routinely monitored using serial ultrasound scans (preferably vaginal scan as it gives a better image than abdominal scan). The number of follicles is counted and the diameters of the growing follicles are measured. The ultrasound is also used to measure the thickness of the endometrium and assess its quality for implantation of the embryo. Serial blood samples may also be taken to measure the levels of estrogen and sometimes LH and progesterone. Estrogen production increases as the follicles develop.
After about 10-12 days of the gonadotropin injections, the follicles will almost be mature. When the ultrasound scan indicates a reasonable size and number of follicles and the diameter of the leading follicles is greater than 18 mm. In addition, the lining of the womb is of good thickness and quality. The estrogen levels correspond to the number of growing follicle. You will be asked to stop both the GnRh agonist and the FSH/hMG injections and a different type of injection called human chorionic gonadotropin (hCG) is given in a dose of 5000-10000 iu (recombinant hCG is as effective as urinary hCG). The injection is essential because it simulates the woman’s natural LH surge. This surge also initiates the final growth spurt of the eggs. hCG injection is carefully timed and is usually given at night to allow egg collection to be performed at a convenient time, about 36 hours later. The number of follicles is no guarantee of the number of the eggs that will be collected.
hCG. HCG is given in a dose of 5000-10000 iu. There are two different types of HCG (recombinant hCG and urinary hCG). Recombinant hCG is as effective as urinary hCG but more expensive. HCG is essential because it simulates the woman’s natural LH surge. This surge also initiates the final growth spurt of the eggs. hCG injection is carefully timed and is usually given at night to allow egg collection to be performed at a convenient time, about 36 hours later. The number of follicles is no guarantee of the number of the eggs that will be collected.
Egg collection. This is usually performed in the morning or early afternoon, approximately 36 hours after the hCG injection. Some clinics allow the male partner to attend the egg collection procedure if their wives have the operation under sedation. A monitor connected to the microscope will allow you to view the eggs when collected.
Methods of egg collection. Several methods can be employed to collect the eggs, these include:
Vaginal ultrasound guided egg collection. This is the most common technique; it is a minor and safe surgical procedure usually performed under sedation or a general anesthetic. Sedation is a safe and ecceptable method of providing pain relief for egg collection.
A vaginal ultrasound probe with a fine hollow needle attached to it, is inserted into the vagina. Under ultrasound guidance, the needle is then advanced from the vaginal wall into the ovary to suck out the fluid from the follicle which contains the egg. Each egg is removed in turn through the needle by a suction device. Follicle flushing is not associated with improvement in pregnancy rates or the number of eggs collected, but does increase the duration of the procedure and associated pains. The whole procedure takes about 20-30 minutes.
You may experience some mild discomfort following the procedure, but this will be relieved with painkillers. Antibiotic is usually given to prevent infection.
Abdominal ultrasound guided egg collection. Occasionally, egg collection is performed by passing a needle through the abdominal wall into the ovaries under ultrasound guidance. This is usually performed if the ovaries are abnormally placed.
Laparoscopy. Originally, eggs were always collected laparoscopically. This method of egg collection is hardly ever used nowadays, as it requires a general anesthetic, in addition to the risks of laparoscopy.
The average number of eggs collected is about 12 depending upon the number of follicles present. Not every follicle contains an egg. Occasionally, no eggs are collected, so-called “empty follicle syndrome”. The reported incidence is about 1%. Sometimes, giving another dose of hCG and scheduling another egg collection 24 hours later could salvage the cycle. The cause of empty follicle syndrome is unknown, but it is possible that it is a drug related rather than a clinical problem.