About eight weeks. So by the time the woman has missed her second period she realizes she s pregnant. Remember back to your freshman medical school days, your embryology days. If you raise your core body temperature enzymes are temperature specific. Enzymes are involved in critical developmental pathways so hyperthermia can be a teratogen.
Cigarettes clearly are.
Not just low birth weight but at least associated with cleft lip and cleft palate, with an increased incidence. You know about radiation exposure. Don t irradiate a woman until you ve documented that she is not pregnant. Seizure disorder and anticonvulsants are very common. Sometimes can t be avoided.