The study population was then divided into three Body Mass Index (BMI) classes based on measured maternal weight and height in early pregnancy (gestational week 10-12); normal weight (BMI <25) , overweight (BMI 25-29.9) and obese (BMI ≥30) . Maternal obesity (BMI ≥30) was also subdivided into obesity class I (BMI 30-34.9) obesity class II (BMI 35-39.9) and obesity class III (BMI ≥40) as suggested by WHO.