Why, after IVF procedure, some got pregnant and some not?
Patients often ask how many amount of follicles they have, if their follicles’ quality are acceptable, or what their chances of pregnancy are. The answers, to all these questions, depend on the ovarian reserve and the quality of ovary they have.
Ovarian reserve is a term that is used to determine the capacity of the ovary to provide egg cells that are capable of fertilization resulting in a healthy and successful pregnancy.
Ovarian Reserve Tests
Age Female reproductive aging is a process that follows the generally accepted theory that over time, oocytes decrease in quantity and quality and do not regenerate. In uterus, there is a rapid multiplication of germ cells starting at six to eight weeks. By the time the female fetus is at 16-20 weeks, she has a peak of six to seven million eggs.
This number declines to one to two million eggs at birth, falling even further to 250,000 to 500,000 eggs at puberty. Every month, a certain number or percentage of immature eggs is selected for maturation.
One of these eggs will ovulate and the rest will regress, die and be reabsorbed into the ovary through atresia. The number of eggs selected is dependent on the number of immature eggs in the pool.
Quality of Eggs The rates of abnormality in eggs are much higher in older patients. With the age lower than 35, only 10% of patients found to have abnormal eggs. As the age rises up to 40 years old, there’s a chance of abnormality at 30%, and continues up to 40% at the age of 43. By the time the number of age reaches up to 45, the chance is doubled up to almost 100%. Microtubules, known as a spindle, play a crucial role in egg developing; they pull and hold eggs’ chromosomes to complete the development of the eggs, making them to become matured. As the woman ages, the quality of microtubules declines; easier to be tear and destroyed.
Therefore, the state called non-disjunction happens, followed by an abnormal embryo with trisomy 13, trisomy 18, or trisomy 21.
Medical History Women with history of giving birth, which indicates a good quality of eggs, have a high chance of pregnancy while unsuccessful pregnancy history predicts a less successful outcome.
Antral follicle count (AFC) is performed with high quality ultrasound equipment to evaluate a woman’s ovarian reserve by counting and measuring small follicles (about 2-9 mm in diameter). If the number of eggs is lower than 6, it is predicted the low function of ovary.
- Advantage: Quick and easy, possible to know the approximately number of eggs before starting the treatment.
- Disadvantage: require professional’s performance.
Basal FSH day 3 is a measurement of FSH hormone routinely taken on Day 3 of the patient’s menstrual cycle. A good quality of egg will resulted in high levels of estradiol and inhibin B hormones, and low level of FSH hormone. The signs of low ovary function include; levels of FSH hormone more than 10 mIU/mL and of estradiol less than 80 pg/ml.
Advantage: Quick and easy. Disadvantage: Level of FSH hormone changes in every month, and if a patient takes estradiol or progesterone pills such as birth control pills, the result might be lower than it should be.
AMH Antimullerian hormone (AMH) is a hormone produced by ranulose cells of growing preantral and small antral follicles.
Advantage: The level of hormone is stable and related directly to the numbers of eggs in the ovary, high in accuracy and reliability. Disadvantage: High cost and no global standard.