I have a theory that if a woman's pre-pregnany stomach is bigger then her baby will generally weigh more than the babies where the mothers hips are bigger than her stomach. Ie apple shaped women have heavier babies than bigger-hipped/smaller-stomach pear shaped women. This might explain why subsequent babies born to a woman are sometimes heavier (basically the womb space inside is more accommodating as the stomach has stretched, so the baby grows bigger as a result. It might also explain why petite women sometimes get heavy babies - they might be small mothers, but if their girth is large, their baby will be large. It's just a theory - anyone else noticed this trend?