How does maternal age and body mass index (BMI) affect IVF success?

This study investigated the effect of age and body mass index (BMI) on pregnancy outcomes in women undergoing in vitro fertilization (IVF).

They found that increasing age and BMI were associated with poorer pregnancy outcomes.

Infertility is an increasing problem worldwide. Obesity is also becoming more common. The impact of obesity on infertility is unclear. Some studies suggest a healthy body mass index (BMI) is important for fertility treatment success. Obesity is linked to conditions that affect fertility. Polycystic ovarian syndrome (PCOS) is one of these conditions. Pregnancy outcomes are lower after fertility treatment in women with obesity. Pregnancy outcomes include clinical pregnancy rate (CPR) and live birth rate (LBR). Weight loss is recommended prior to undergoing fertility treatment. However, lowering BMI does not always result in fertility treatment success.

Increasing age is also associated with infertility. Focusing on weight loss may result in delaying fertility treatment. This means the woman is older when undergoing fertility treatment. It is unclear if the combination of increasing age and BMI may influence pregnancy outcomes in women undergoing fertility treatment.

This study included 68,026 IVF cycles. Pregnancy outcomes were obtained from patient medical records. These included implantation rate (IR), miscarriage rate (MCR), CPR and LBR. BMI was categorized using standard definitions. Obese is a BMI of 30 or higher. 

44.8% of women were categorized as overweight or obese. Women with obesity had fewer oocytes (eggs) retrieved. IR, CPR, LBR were lower in patients with higher BMI. MCR was greater in patients with higher BMI. IR, CPR, and LBR were lower with increasing age. In women with high BMI, decreases in the LBR were smaller in higher age groups compared to lower age. This means the effect of BMI on LBR is lower in older women.

They concluded that increasing age and BMI were associated with poorer pregnancy outcomes in women seeking fertility treatment.

This study suggests that BMI may have less of an effect on pregnancy outcomes in women of older age. However, a healthy BMI is important for maternal health during pregnancy. More research is needed.

If you have any concerns regarding infertility, please consult with your physician.