Many expecting parents rely on oral sex as an alternative to intercourse. But experts say, it can be dangerous in rare occasions. If you are pregnant and enjoy having oral sex, this article is a must-read for you.Though your protruding belly might make it difficult for you to switch positions but yes having sex during pregnancy is completely safe. However, certain conditions like cervical weakness might force you not to have intercourse in the later trimesters.So, in order to maintain some semblance of a sex life, many expecting couples seek other forms of sexual gratification including oral sex.According to an expert from the Department of Obstetrics, Gynaecology and Reproductive Sciences at the Yale University School of Medicine, oral sex is fine for the foetus and the mother if you are cautious.For starters, a serious complication can arise if the partner blows air into the vagina. The blood vessels in the vagina are already dilated at this time, blowing air into the vessels can cause an air embolism. This can block a blood vessel, which can negatively impact your cardiovascular system and even cause death in rare cases.The air bubble can also land in the placenta and impact fetal development. Though air embolism is a very rare event, it can be easily avoided, assures the expert.The increased blood volume during pregnancy can make your capillaries more sensitive. This means that blood vessels may rupture with even light friction.Another major concern regarding oral sex during pregnancy is contracting a sexually transmitted infection (STI) like HIV, gonorrhoea or chlamydia. The thing of utmost concern is that the herpes (Read more: What is herpes and its prevention ) simplex virus can get passed on to the fetus. This can cause complications like neurological damage, brain inflammation and even death of the baby.The foetus has the highest chances of developing neonatal herpes if the mother gets it during the third trimester, according to the American Sexual Health Association. This can happen because a pregnant woman’s immune system can’t make antibodies against the virus. Women infected with herpes need to get a C section.- Have oral sex only with a partner who is tested negative for STIs.- Do not have oral sex if your partner has open cold sore (Cold sores are a common viral infection. They are tiny, fluid filled blisters around your lips caused by herpes simplex virus) or feels he is developing one, as this could be a sign of herpes.- Do not have unprotected third-trimester pregnancy sex with anyone who has ever had a cold sore.The views expressed in this article should not be considered as a substitute for a physician's advice. Please consult your treating physician for more details.