6 Reasons Why IVF Can Fail and What Affects IVF Success?

In vitro fertilization (IVF) is one of the most widely used assisted reproductive technologies. It has helped many couples and individuals who experience difficulty conceiving. IVF may be recommended for several causes of infertility and involves fertilizing an egg with sperm in a laboratory before transferring the resulting embryo into the uterus. This article explains how IVF works, when it may be recommended, possible reasons for IVF failure, and some important facts about the treatment.

What is In Vitro Fertilization (IVF)?

In vitro fertilization (IVF) is a fertility treatment in which eggs are collected from the ovaries and fertilized with sperm under laboratory conditions. The resulting embryos are then monitored before one or more suitable embryos are transferred into the uterus.

The IVF process generally involves the following steps:

1. Ovarian stimulation: Fertility medications are given to stimulate the ovaries so that multiple follicles and eggs can develop during the treatment cycle. Ultrasound scans and blood tests may be performed to monitor follicular development and hormone levels.
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2. Egg retrieval: Once the follicles have matured, the eggs are collected through a minor procedure called egg retrieval or follicular aspiration. A thin needle is guided through the vagina into the ovarian follicles, and the eggs are collected using gentle suction.
3. Insemination and fertilization: The collected eggs are combined with sperm in the laboratory. In some cases, especially when fertilization is expected to be difficult, a single sperm may be injected directly into an egg using intracytoplasmic sperm injection (ICSI).
4. Embryo culture: Fertilized eggs are monitored in the laboratory as they develop into embryos. Some embryos may develop into blastocysts around five to six days after fertilization. In selected cases, genetic testing may also be considered before embryo transfer.
5. Embryo transfer: A suitable embryo is transferred into the uterus using a thin catheter passed through the cervix. If the embryo successfully implants into the uterine lining, pregnancy may occur.
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Conditions Where IVF May Be Used

In vitro fertilization may be considered in several situations, including:

• Absent fallopian tubes
• Blocked or damaged fallopian tubes
• Age-related decline in fertility
• Endometriosis
• Male factor infertility
• Azoospermia, where sperm are absent from the ejaculate and sperm retrieval may be possible in selected cases
• Oligospermia or low sperm count
• Certain ejaculation or sexual function disorders
• Unexplained infertility
• Repeated unsuccessful cycles of ovulation induction or IUI

Reasons Why IVF May Fail

IVF does not result in pregnancy in every treatment cycle. Several factors may influence the outcome of an IVF cycle, including:

1. Age of the woman: As a woman gets older, both the number and quality of available eggs generally decline, which may affect IVF success.
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2. Embryo quality: Even an embryo that appears healthy in the laboratory may not always implant successfully in the uterus. Embryo development and chromosomal health can influence implantation.
3. Ovarian response: Some women may produce fewer follicles or eggs than expected despite ovarian stimulation, which can reduce the number of embryos available for treatment.
4. Implantation-related factors: Conditions affecting the uterus or endometrium may interfere with implantation. These may include uterine polyps, fibroids, abnormalities of the uterine cavity, or problems with the endometrial lining.
5. Lifestyle factors: Smoking and certain other lifestyle factors may negatively affect fertility and treatment outcomes.
6. Chromosomal abnormalities: Some embryos may have chromosomal abnormalities that prevent successful implantation or ongoing pregnancy. The likelihood of these abnormalities generally increases with maternal age.
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IVF Facts

Several factors can influence the outcome of IVF treatment. Some important facts to understand include:

1. IVF success rates vary: IVF success cannot be represented by a single percentage for everyone. Outcomes vary depending on age, ovarian reserve, embryo quality, sperm factors, underlying fertility conditions, previous treatment history, and whether success is measured as pregnancy or live birth.
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2. Age is an important factor: Younger women generally have higher IVF success rates because egg quantity and quality tend to decline with age. However, age is only one of several factors considered when estimating the chances of treatment success.
3. Embryo quality matters: The development and quality of embryos are important factors in IVF treatment. In selected cases, preimplantation genetic testing may be discussed to assess embryos for specific genetic or chromosomal conditions.
4. Single embryo transfer may be preferred: When appropriate, transferring a single suitable embryo can help reduce the risk of multiple pregnancy. The number of embryos transferred is decided based on individual clinical factors and fertility specialist recommendations.
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IVF has helped many couples and individuals overcome different fertility challenges. However, treatment outcomes vary considerably, and IVF may not be the most appropriate option for everyone. A detailed fertility evaluation can help determine whether IVF is suitable and what factors may influence the chances of success.

NU Fertility provides fertility evaluation and assisted reproductive treatments for couples experiencing difficulty conceiving. Depending on the underlying fertility condition, specialists may recommend treatments such as IVF and ICSI as part of an individualized treatment plan. Patients can also consult fertility specialist Dr Sneha S to understand their fertility concerns and available treatment options.

References:

1. ART Success Rates. Centers for Disease Control and Prevention (CDC).
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2. Fertility Treatment Trends and Figures. Human Fertilisation & Embryology Authority (HFEA).
3. In Vitro Fertilization (IVF). MedlinePlus.
4. IVF by the Numbers. Penn Medicine.
5. Why Does IVF Fail? The Fertility & Gynaecology Academy.