Do babies conceived by mothers on the Pill have weaknesses or abnormalities?

Question from a reader:

I was wondering if born babies conceived by mothers on the Pill have any weaknesses or abnormalities since they grew in a compromised womb, or, to use you analogy, poor soil. 

Answer from Jessica Farnsworth, M.D.:

Pregnancies conceived while on the pill or shortly after stopping the pill have an increased risk of miscarriage.  The question seems to be: What is the teratogenic (ability of a substance to cause a defect in a baby) potential of birth control pills?  The older, higher doses of birth control pills were associated with several birth defects.  Now that the dosages of estrogen and progesterone have been lowered, there are far fewer birth defects noted.  Some studies have shown no increased risk of birth defects caused by birth control, but the quality of these studies is not always great, and it is very difficult to set up a good study, as it would unethical to expose pregnant mothers to a potentially toxic substance.