LEP and obesity due to melanocortin 4 receptor deficiency: This large study included 223 women in obesity class I and 120 women with morbid obesity (obesity class II and III) and showed higher leptin levels during and after pregnancy in women with morbid obesity, compared to women in obesity class I. Thus, at each leptin measurement during and after pregnancy maternal leptin levels were significantly higher among women in obesity class III compared to obesity class I women.