Not necessarily, although it is recommended to have an adequate Body Mass Index (BMI) to obtain a greater number of eggs and avoid possible risks. A normal BMI is between 18 and 25.
Women who are overweight or obese are more likely to suffer infertility, since estrogen production is affected, among other things. In addition, for ovarian stimulation in obese women a higher dose of hormones is needed to obtain a good response. There is also a greater probability of obtaining immature and poorer quality eggs.
You can find out more information in this article: Infertiilty and BMI