Predicting IVF Success 101:
Univfy’s Fertility Chronicles is pleased to present an occasional blog series explaining the many fertility factors, such as age, ovarian reserve, body mass index, and others, that determine your personal probability of having a baby with IVF. Univfy IVF Prediction Tests analyze the sum total of all these factors unique to you to determine your personal probability of IVF success. We hope that explaining these factors will give you a better understanding of Univfy IVF Prediction Tests’ ability to help you and your fertility doctor make more informed and confident decisions about your fertility treatment. Welcome to the blog series, “Predicting IVF Success.”
---Mylene Yao, M.D., CEO and Co-founder, Univfy Inc.
Like many things in life, moderation is best when it comes to fertility factors for IVF success. Women who fall far outside the normal body mass index (BMI) and are either very under- or overweight are likely to have a reduced probability of pregnancy with IVF. It has long been appreciated that abnormal weight can disrupt hormonal function and timely ovulation, making it more difficult to become pregnant in natural cycles.
You would think that since IVF bypasses the need for natural ovulation, BMI should not have much impact on IVF success. However, multiple studies have shown that obesity, in particular, is a highly negative factor for predicting IVF success. Physicians may recommend weight loss before attempting IVF to increase the chances of a successful cycle, although it’s not clear whether weight loss does indeed improve the chances for each patient.
But why would a high BMI decrease your chances of having a baby with IVF? High BMI has been associated with poorer egg and embryo quality, and there may be other effects at the molecular level that we do not yet fully understand.
Hormonal imbalance and embryo quality are not the only possible problems arising from obesity. A high BMI represents a technical challenge for IVF patients at egg retrieval, because ovaries are often pushed up high and away in the abdominal cavity, making it difficult to reach and recover all the mature eggs with the retrieval needle.
Moreover, the presence of excess fatty tissue may result in poorer image quality on the ultrasound, making it difficult to recover every egg. Fewer eggs recovered per cycle mean fewer possible embryos for transfer, reducing the likelihood of pregnancy from IVF.
If IVF is successful, the obstetrician is also concerned about complications during the pregnancy, as well as labor and delivery, because the mother’s pre-pregnancy weight is associated with weight gain during pregnancy and the baby’s birth weight. Larger babies are at risk for difficult birth and birth injuries.
Though research has shown that a high BMI can hurt your chances of IVF success, remember that research results from the general population cannot be directly applied to your specific chance of pregnancy with IVF. Your BMI must be considered as part of your whole clinical picture, including multiple fertility factors, such as your reproductive history, ovarian reserve, age, partner’s sperm count, and cause of infertility. For perspective, some women with normal BMI may have other factors working against them. So, while having a high BMI does not help, it is the holistic picture that is important in figuring out your next-steps.
Should a patient who is age 39 with a BMI of 30 (high) take three months to lose 10 pounds before taking her IVF treatment? She should first find out her chances of IVF success now. Any delay in IVF can also cause her age and ovarian reserve to worsen by the time she actually starts her first IVF cycle.
At the opposite extreme, if you have a very low BMI (under 19), becoming pregnant may be more difficult. BMI is a measure of your body’s available energy reserves for taking on physical and physiological challenges. You need sufficient body fat reserves to ovulate and support your pregnancy. In fact, if BMI is too low, your doctor may ask you to gain a bit of weight before conceiving, so that you build up some reserve to help you through the first trimester, which can be especially challenging if you turn out to have nausea and vomiting along with decreased appetite.
Other clinical conditions (chronic diseases, such as diabetes, heart disease, autoimmune diseases, or unhealthy lifestyle factors, such as smoking) can also affect the expected success rate with IVF for a particular patient.
Smoking, in particular, has been shown in numerous studies to be a negative predictor of IVF success for both men and women.
Smoking and BMI are considered in Univfy IVF Prediction Tests to produce a probability of pregnancy for a specific patient. At this time, it’s not possible to include chronic medical diseases, such as diabetes, heart disease and others, in the model, because of the many gradations of these illnesses. In general, patients who are getting IVF treatments tend to be healthy, so it is difficult to gather sufficient data for our predictive test to incorporate this type of analysis. If you have these medical illnesses, and your doctor recommends IVF, Univfy IVF Prediction Tests can give you and your doctor a much more accurate reference point with which to develop the best treatment plan for you.
Visit Considering IVF for more fertility health information and interactive tools to personalize your fertility path.