Phenergan has been used for the treatment of morning sickness, which causes pregnant women a lot of trouble especially in the first trimester of pregnancy. Morning sickness may not affect all women when they are pregnant and it may not affect them pregnancy after pregnancy. It is highly dependent on a woman as it is not absolute- there are women who have never had morning sickness and some who have morning sickness up to the last month of pregnancy.. This is a condition that is caused by the presence of the human chronionic gonadotrophin hormone in the body and its imbalance with the regular hormones. Phenergan is a drug used to manage this condition and if you are planning to use this drug you may wan to know that it is bound to cause yor baby some respiratory problems espeally when it is used all through the pregnancy. It is very important to weight the potential benefits and the risks of Phenergan when using it. Medical professionals need to know the medical histories of the patients they are prescribing Phenergan to before they make the prescription. It is also known to lead to miscarriages in the early stages of pregnancy so it is not really safe for the baby in pregnancy.