What is an Immature Ovum?
One of the more gratifying moments in the midst of a rigorous IVF cycle is learning how your body is responding to the infertility medication. Each follicle represents the promise of an egg, then an embryo, which gets you one step closer to pregnancy and your long-awaited child. But what happens when the ovaries aren’t responding in the way you’d hoped? You may hear mention of an immature ovum. We’ll explore what this means, why it happens, and how it can be treated.
What is an immature egg?
An immature egg, referred to medically as an immature ovum, quite literally isn’t mature enough to be fertilized by sperm. Eggs, which develop within follicles in the ovary, must undergo a required division of cells in order to prepare for fertilization.
Can sperm fertilize an immature egg?
No. The division of cells, called meiosis, reduces the number of chromosomes in the nucleus from 46 chromosomes to 23. It is a process both egg and sperm must complete. Without this division, the egg or sperm will have too many chromosomes and cannot produce a viable embryo.
How many eggs are women born with?
At birth, a newborn has all the follicles she will ever have – about one million. Amazingly, a female fetus has 6 to 7 million, so by the time she’s born she’s already lost the majority. The decline in eggs only continues as she ages; by puberty, she will have about 300,000. It’s possible to lose up to one thousand eggs per month, so by the age of 25 she may only have about 200,000 available. Of those eggs, only about 400 to 500 will ever actually be ovulated. The numbers continue to drop steadily until she reaches menopause, typically in her 50s.
Can immature eggs be released during ovulation?
Technically, yes – this is known as early ovulation. If an egg is released before day 11 in a woman’s cycle, it doesn’t have time to mature and develop within the follicle. And without a mature egg to fertilize, it is impossible to achieve a pregnancy.
Thirty percent of women’s infertility is related to ovulatory disorders such as early ovulation and anovulation, a condition in which ovulation doesn’t occur at all. In about half of the cases of anovulation, normal follicles aren’t even produced – which means an egg doesn’t have the opportunity to mature.
Is there treatment for immature eggs in ovaries?
Yes. Because specific hormones are responsible for the production and maturation of follicles, it is possible to mimic them. But first, your doctor will likely want to confirm if your eggs are immature by testing your follicle-stimulating hormone (FSH) level and your anti-mullerian hormone (AMH) level, which reflects your ovarian reserve. An ultrasound to check your antral follicle count is helpful too; while not always the case, research shows that the number of active antral follicles is a good indication of ovarian reserve. A normal number is 6 to 10; fewer than 6 indicates low ovarian reserve.
Women with polycystic ovarian syndrome (PCOS) often fall in this category due to the lack of hormones necessary for eggs to fully mature. In fact, 70% of ovulatory issues are related to PCOS.
If you ultimately decide to undergo infertility treatment, your doctor will likely start a regimen of oral fertility medications, such as Letrozole or Clomid, to help stimulate the ovaries. Other alternatives include injectable fertility medications or gonadotropins. Gonadotropins contain follicle stimulation hormones (FSH), luteinizing hormones (LH) or a combination, and encourage the ovaries to produce more eggs. This is the protocol for egg donor medication, too.
During the in vitro fertilization process (IVF), the stimulation protocol can be adjusted as necessary if it appears there are too many immature ova. This can improve the rate of maturation and, hopefully, increase the number of mature eggs that will be available at retrieval; this is why regular monitoring is so important. These drugs are used in addition to human chorionic gonadotropin (hCG) in the form of a trigger shot about 36 hours before egg retrieval.
Whether you are going through the process yourself for a surrogate IVF cycle, or if you’re working with an egg donor, mature follicles are key to your future success. Our team is ready to assist you every step of the way.