By Dr. Mary Hinckley
While it is well known that in vitro fertilization (IVF) pregnancy rates are lower in women who are obese, few studies have looked at the effects of obesity on success rates of follicle stimulating hormone/insemination cycles. And, the studies that do exist show conflicting results.
For example, a recent study done in Oklahoma by Dr. LaTasha Craig, looked at 1120 insemination cycles from 2007 to 2010. The female patients were 33 years old on average, and the leading reason for their fertility treatment was male factor infertility. Study results showed the following success rates for women taking follicle stimulating hormone fertility drugs while undergoing intrauterine insemination cycles (FSH/IUI):
- Underweight women had the lowest chance of success with FSH/IUI at 7 percent.
- Normal weight women had a 12 percent chance of success.
- Overweight women had a 15 percent chance of success.
For comparison, another study done on 45,163 embryo transfer patients showed that for every increase in BMI point over 39 kg/m2, there was a four percent lower chance of conception. So what is a patient to do, and how can we interpret study results on weight and fertility treatment success rates?
Well, pregnancy rates may not drop for patients that are obese and only need inseminations. However, the increased risks for obese women that do become pregnant, and their babies, are well known. Obese and overweight women are at a higher risk for the following complications when pregnant:
- Heart disease
- High blood pressure
- Fetal malformations
- Need for caesarian sections
These risks should cause all women to pause and be thoughtful about their weight and fertility strategy. In fact, it is strongly recommended that all obese and overweight women achieve a normal BMI prior to conception. For some, this will actually help them conceive WITHOUT needing fertility treatment.
Here at the Reproductive Science Center of the San Francisco Bay Area, we recommend the following for obese or overweight women who are trying to get pregnant:
- If you are less than 37 years old with normal ovarian reserve, we recommend that you start an aggressive weight loss program before you begin fertility treatment.
- If you have limited ovarian reserve or are older than 37, we recommend a careful and through assessment of your health. That way, if you have diabetes or high blood pressure, you will have an opportunity to get your disease under control with drugs or lifestyle changes prior to conception.
- If you have a BMI over 40, you cannot undergo egg retrieval for IVF due to concerns from an anesthesia standpoint. So weight loss is a must.
- If you have a BMI over 40 and co-morbidities (like high blood pressure or diabetes) we recommend that you treat the co-morbidities as well as lower your BMI to below 40 before starting ANY fertility treatment, even inseminations.
It is our goal at RSC to create healthy families. By recognizing, treating, and preventing all causes of infertility and pregnancy complications, we are one step closer to our goal.
Dr. Mary Hinckley is a leading reproductive endocrinology and infertility specialist at the Reproductive Science Center of the San Francisco Bay Area. She has extensively published articles in peer-reviewed journals on blastocyst transfer, avoiding triplet pregnancies, monozygotic twinning, operative hysteroscopy, correction of uterine anomalies, and biochemical pathways involved in ovulation and fertilization. She serves as a member of the Society for Reproductive Endocrinologists, the Christian Medical and Dental Society and the American Society for Reproductive Medicine. Her areas of interest include laparoscopic surgery, premature ovarian failure, oocyte freezing, and recurrent pregnancy loss. Dr. Hinckley offers infertility education on YouTube.