Moderate obesity is increasing in pregnancy. Moderate obesity is a pre-pregnancy BMI (Body Mass Index) of 25-40. You can calculate yours. You will be able to deliver your baby safely, with extra medical help. 
Make sure to follow a healthy diet in pregnancy as recommended by your doctor. For a single baby 11-20 pounds and for twins 25 or more pounds are recommended.
You will need extra monitoring for diabetes and high blood pressure and special ultrasounds.
lf you have trouble sleeping, you may need extra oxygen because the increased weight from the pregnancy may cause sleep apnea.
Choline levels are not dependent on BMI. Your choline levels may be high or low. You are likely to need choline supplements, along with prenatal vitamins, regardless of your weight.
Obesity does adversely impact fetal brain development, but the effect is not generally reversible with higher choline levels. Choline and folic acid with prenatal vitamins will protect your baby from other risks. Both depression and infection are more common when the mother is obese. Obese women are also more likely to develop a liver disease in pregnancy. Extra choline protests the mother's liver as well.
 
Read more:Pregnancy and obesity: Know the risks. The Mayo Clinic text