Medical experts have developed a set of requirements for surrogates that produce the best success rates. Women with a BMI above 32 are at higher risk of developing complications during pregnancy such as preeclampsia, gestational diabetes, and other conditions that can affect the surrogate and the baby. Additionally, studies have shown that women with a high BMI may have lower implantation and pregnancy rates following IVF. Women with a high BMI may respond differently to fertility medications. They may require higher doses of medication to stimulate ovulation, which can increase the cost and the risk of side effects.