It can be frustrating when you had sizable numbers of eggs retrieved but only a few eggs matured. Let’s understand this situation, it’s probable causes and solutions. IVF process is an advanced fertility treatment, where every follicle promises to develop an egg, which can be implanted to yield a pregnancy. Eggs & sperm are an important component of IVF success but more relevant are mature eggs & competent sperm. These are the basic requirements for a full-term progeny. Why do some eggs not mature? For that matter, What do we classify as an ‘immature egg’? An immature egg or an immature ovum cell, is one that has not yet developed to a stage where it is capable of undergoing fertilization by sperm. An immature cell should undergo a division of cells by Meiosis 1 for fertilization to occur. Unless and until the egg completes meiosis 1, the egg cannot be fertilized. To complete meiosis 1, it has to have a high level of Luteinizing Hormone (LH) in the follicle. The “LH surge” occurs in a natural menstrual cycle (or the hCG trigger in an IVF cycle). hCG stands for human chorionic gonadotropin. This pregnancy hormone closely resembles the Luteinizing hormone. This is why it can be used as a trigger instead of LH directly. Follicles with a diameter of ~16-18mm will probably have the highest chances of becoming mature eggs. The eggs that are in smaller follicles, don’t respond to the LH surge and are called immature ovum. Immature eggs are diploid (have 46 chromosomes. After the egg completes meiosis 1, it becomes a haploid with 23 chromosomes and extrudes the other 23chromosomes’ polar bodies. Can the active sperm fertilize an immature egg? No. Due to meiosis, 46 chromosomes reduce to 23. In the meiosis 1 process, both egg and sperm must be complete. Without meiosis 1 division, the egg or sperm will have many chromosomes and is incapable of producing a viable embryo. How does an embryologist know which eggs are mature? An egg has an outer shell called the zona pellucida, which protects the internal structures and helps in fertilization. Internal structures which are developed usually are cytoplasm, organelles and DNA. Eggs are classified as mature when a small cell (called the polar body) can be seen within the shell of the egg. One of the reasons there are plenty of follicles but they do not develop into mature eggs is PCOD. For women in whom PCOD is serious enough to prevent conception, IVF is the best option. 1.Response to IVF medications: quality matters. The very important aspect of IVF treatments are medications, timing & quality of medications. In IVF stimulation, there are many medications given to optimize the conditions of growth, implantation etc. Many times, this medicine induces the response but not to the extent it is expected. Very often, the retrieved eggs may not be matured & degenerate fast. 2. Inadequate dosage and timings of stimulant or trigger medicines. When follicles have reached a certain size, the fertility team will take a call for the trigger medicines. These medicines help in ovulation and maturation of eggs without much degeneration. Then the eggs are released from the follicular wall. If the timings and dosage of the medicines are inadequate, there are possibility eggs will not mature optimally. 3. Conditions like PCOS or Diminished Ovarian Reserve: it is often noted that, in the case of PCOS, there are many follicles which may not reach up to the maturation phase. Effects of PCOS on egg quality depend on the women’s age. We have seen in the past, as age increases, the quality of eggs may decrease. PCOS patients often have increased androgen levels. The silver lining for PCOS cases is, at younger ages (approximately till age 35), PCOS, whether of the “classical” or “lean” type, does not affect egg quality. In older “lean” PCOS women, who usually have become hypo-androgenic, egg quality is negatively affected significantly. So to overcome this issue, androgen levels need to be appropriately pre-supplemented, starting at least 6-8 weeks before the IVF cycle start. Is there a treatment for immature eggs? Yes. There are specific hormones which are responsible for the production and maturation of follicles. Your doctor will confirm egg maturity by testing your follicle-stimulating hormone (FSH) level and anti-mullerian hormone (AMH), which confirm the ovarian reserve, correlating these values with an ultrasound to check your antral follicle count. Research shows that the number of active antral follicles is a good indicator of ovarian reserve. A normal number is between 6 and 10; less than 6 antral follicles indicate low ovarian reserve. There are many treatments available to conceive even with a low egg count. Nevertheless, getting the diagnosis and treatment well in advance is the key and the age of the couple is still the important factor. In IVF, well-planned cycles are an art of science and the experience of fertility experts matters the most. Every trigger of follicles that produce eggs further transforms them into embryos which are mature and competent enough to create a baby. Every phase of development needs to be monitored with quality medication, proper dosages, timings and protocol in place. What a regulated and specialized process it is! We at Yash IVF, have an excellent embryology lab, where the journey of life begins. This Lab has an in-house, UK-trained embryologist with over 5 years of experience and a well-trained team of Junior embryologists and IVF technicians. We are a reference centre for such cases where egg maturity is an issue for some reason or the other, be it PCOD or Endometriosis or some other ailment.
