If you are obese or overweight, try to lose some weight before becoming Pregnant.

http://www.patient.co.uk/health/planning-to-become-pregnant

Overweight and obesity

If you are obese or overweight, try to lose some weight before becoming pregnant. Women who are overweight or obese have a greater risk of pregnancy complications such as pre-eclampsia, stillbirth and the need for a caesarean section compared with women who are not overweight. Basically, the more obese you are, the greater the risk.