The Practice Committee of the American Society for Reproductive Medicine (ASRM) recently published a report that included the effects of obesity on in vitro fertilization (IVF) success rates. Here is a brief summary of seven key findings.
Obese Women Need Higher Doses of Drugs
Obesity is associated with higher doses of medications to stimulate the ovaries. Obese women also take longer to respond, have increased cycle cancellation rates, and fewer eggs retrieved.
Obese Women are Less Likely to Get Pregnant
IVF pregnancy rates are lower in obese women. The age-adjusted odds of live birth are reduced in a BMI-dependent manner by 37% (BMI, 30.0– 34.9 kg/m2), 61% (BMI, 35.0–39.9 kg/m2), and 68% (BMI, >40.0 kg/m2) compared with women with a BMI of 18.5– 24.9 kg/m2.
In other words, the chances of having a baby decrease as the woman’s weight increases.
Obesity Affects Eggs and Embryos
Egg quality, fertilization rate and embryo quality all decrease in obese women. This means that eggs retrieved may result in a failed IVF cycle.
Obesity Affects the Uterine Lining
The uterine lining is less receptive in obese women. This has been studied in donor egg recipients as well as in surrogate cycles where the live birth rate has been shown to be lower in obese women.
Higher Risk of Pregnancy Loss is Linked to Obesity
Obesity is linked with a higher miscarriage rate (a 31% increase) when compared to normal weight women.
Pregnancy is Riskier for Obese Mothers
Pregnancy outcomes are poorer in obese women. Obese women have a increased risk of diabetes, high blood pressure, preeclampsia, preterm delivery, still birth, cesarean or instrumental delivery, labor complications (shoulder dystocia), fetal distress, early neonatal death, and small- as well as large-for-gestational age babies.
Greater Risk of Birth Defects
There is an increased risk of birth defects in babies born to obese mothers. These include spinal defects, heart defects, cleft lip, cleft palate, etc.
Reducing Body Weight Reduces Risk
The good news is that a lot of these problems can be avoided by losing weight prior to getting pregnant. Weight management in all individuals is best achieved through a lifestyle modification program that combines diet and exercise.
Behavioral interventions that help include working with a psychologist and stress management. (The use of medications and bariatric surgery for weight loss are beyond the scope of this blog.)
Small Changes Lead to Big Successes
At InVia Fertility Specialists, we encourage patients to lose weight in order to maximize their chances of a successful outcome. Patients with a BMI greater than 35 kg/m2 are encouraged to lose weight before they can start an IVF cycle. To help with weight loss, we offer the Ideal Protein Diet program. This is a meal replacement program where patients work with a coach. Patients lose an average of 3 – 4 lb a week without feeling hungry or tired.
Even a 7% loss of body weight and increased physical activity (150 minutes a week of moderate activity such as walking) can make a difference. A significant percentage of patients who achieve weight loss will start ovulating (get regular periods), and some will get pregnant naturally.
If you are ready to talk to a fertility specialist to plan your pathway to parenthood, we can help. Make an appointment at one of InVia’s four convenient Chicago-area fertility clinics.
Dr. Karande is Board Certified in the specialty of Obstetrics and Gynecology as well as the subspecialty of Reproductive Endocrinology and Infertility. He is a Fellow of the American College of Obstetricians and Gynecologists and Member of the American Society for Reproductive Medicine.