Polycystic ovarian syndrome and body mass index: what is the effect on pregnancy outcomes after IVF?

This study investigated the effect of body mass index (BMI; a measurement of weight in relation to height) on pregnancy outcomes in women with polycystic ovarian syndrome (PCOS) undergoing assisted reproductive techniques (ARTs). They found that obese women had lower live birth rate (LBR).

Polycystic ovarian syndrome (PCOS) is caused by cysts on the ovaries. This can lead to a number of problems. PCOS is a common cause of infertility. Women with PCOS may not ovulate normally. This can make it difficult to become pregnant. PCOS can also be associated with a higher body mass index (BMI). Women with PCOS can have insulin resistance. This may lead to weight gain. Many women with PCOS may undergo assisted reproductive techniques (ARTs). This includes in vitro fertilization (IVF). 

The effect of obesity on oocyte (egg) quality is unclear. A BMI greater than 30 is considered obese. Some studies suggest obesity can reduce fertility. High BMI may be associated with poorer pregnancy outcomes. However, the effect of BMI on pregnancy outcomes after ART in women with PCOS is unclear.  

This study included 3,079 women undergoing ART. These women had a confirmed diagnosis of PCOS. Pregnancy outcomes were measured. These included live birth rate (LBR) and miscarriage rate (MCR). Other pregnancy outcomes included fertilization (FR), implantation (IR) and clinical pregnancy rate (CPR). Standard BMI groupings were used. BMI greater than 30 kg/m² were considered obese.

IR and CPR were similar across all BMI groups. In obese women, however, LBR was 46% lower and MCR was 3.27 times higher compared to normal BMI (18-24.99 Kg/m²) women. LBR decreased with increasing BMI. The highest LBR was in normal BMI women. 

The authors concluded that obese women with PCOS undergoing ARTs had lower LBR.

A complete fertility history was not available for each patient. This means there could be additional factors affecting pregnancy outcomes. Insulin and glucose levels were also not available. More controlled studies are needed in women with PCOS. 

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