Roughly 30% to 50% of fertilized eggs typically develop into blastocysts, a critical stage in embryo development, though this varies significantly with maternal age and egg quality, with younger patients seeing higher rates (around 50%) and older patients (over 42) seeing lower rates (closer to 39%). This drop-off, known as attrition, is normal, with the most significant losses happening between days 3 and 5/6, but reaching blastocyst stage indicates a healthier embryo with a better chance of implantation.
The average percentage of fertilized eggs making it to Day 5 is between 30-50%. Laboratory conditions significantly impact IVF success rates. Age is a critical factor in determining the percentage of fertilized eggs that develop into blastocysts.
IVF is most likely to fail during the embryo transfer stage. This is when the embryo has the chance to implant into the uterus. If implantation does not happen, it can lead to IVF failure.
Most embryos stop developing and perish within days of fertilization, usually because they have an abnormal number of chromosomes.
Success rates of a blastocyst transfer
In women aged up to 30, the chance of a successful pregnancy is between 45% and 50%. This reduces to a 35% – 40% chance in women aged 30- 39. You are as likely to have a successful pregnancy following the transfer of one blastocyst as you are with two.
As a general rule of thumb, at RMA, which has one of the best embryology labs in the country (as evidenced by the clinic's high success rates), about 80 percent of eggs will fertilize (day 1 success), and of those, about 30-50 percent will make it to the blastocyst stage (day 5 or 6).
While embryo quality is the most common issue, researchers continue to investigate additional factors, including: Other genetic mutations that may affect implantation. Immune system responses that might interfere with embryo development. Uterine conditions, such as thin endometrial lining or undiagnosed abnormalities.
While some implantation factors are beyond our control, there are several habits and actions that can help support this crucial stage.
Between one-third and one-half of all fertilized eggs never fully implant. A pregnancy is considered to be established only after implantation is complete. Source: American College of Obstetricans and Gynecologists.
Jennifer Aniston underwent IVF treatments throughout her late 30s and 40s, a challenging period where she tried everything to conceive, eventually continuing into her early 50s, ultimately deciding to share her private fertility struggle years later in an interview with Allure.
Actress Jennifer Aniston underwent multiple unsuccessful rounds of IVF (in vitro fertilization) during her journey to have children, revealing she tried for years, changed clinics, and experienced several failed cycles before stopping, but has expressed having "zero regrets" about her path. While the exact number isn't specified, she described it as a challenging, multi-year process involving numerous attempts.
Out of 100 women after IVF, up to 20% experience miscarriages. Moreover, 80% of them experience this misfortune during the first trimester. The most dangerous period for miscarriage, according to statistics, is 12 weeks.
Poor quality embryos are one of the most common reasons for failed IVF. Whether you are infertile or just infertile, poor quality embryos can result in IVF cycle cancellation. A poor-quality embryo can be the result of multiple factors, including defective uterus or eggs.
Blastocysts contain chromosomes. If there are chromosomal abnormalities, such as an extra chromosome or a chromosome that's duplicated or deleted, the blastocyst usually won't implant in your endometrium.
D5 blastocysts, especially high-quality D5, resulted in significantly higher clinical pregnancy (58.4% vs 49.2%) and live birth rates (52.5% vs 45%) compared to D6.
Roughly about 50 % of eggs will develop into day 3 embryos and at around 20-25% of eggs will reach the blastocyst stage at day 5.
This 2022 study from Columbia University found that embryos have trouble with duplicating the genome which can result in the embryos cell having too many or few chromosomes. If no embryos made it to the blastocyst stage, that's because there were too many or not enough chromosomes.
For example, women who have chronic health problems, such as high blood pressure or diabetes, who become pregnant may be considered to have high-risk pregnancies—even if the condition is well controlled. Other factors, such as infections, injuries, and disorders of pregnancy, can also put a pregnancy at high risk.
Hormonal changes happen after successful implantation, which can result in positive pregnancy tests. Things that can hinder implantation include alcohol, sex, smoking, stress, excessive caffeine, intense exercises, early pregnancy testing, overanalyzing symptoms, and eating processed foods.
Don't: Smoke, drink or use recreational drugs during the two-week wait. If there's a chance you could be pregnant, don't smoke or drink alcohol. There is no known safe amount of alcohol you can drink while pregnant.
One technique is the endometrial scratch, which removes a bit of the surface layer of the endometrium some weeks before the transfer. In effect the surface of the lining is roughened up a bit, giving more area for the embryo to attach.
1-2 days post embryo transfer - The blastocyst begins to hatch out of its shell and attaches itself to the uterus. 3-4 days post embryo transfer – The blastocyst attaches and connects more deeply into the uterine lining, continuing to implant through day four.
Many factors can affect the implantation potential of an embryo, including sperm and oocyte quality in addition to iatrogenic factors such as laboratory conditions and embryo transfer technique. In addition, many conditions of the uterine cavity may influence the ability of the embryo to implant.
It may shorten the luteal phase (the time after ovulation), making it harder for an egg to implant in the uterus. High stress can also affect egg quality and even delay or prevent ovulation altogether.