Women with morning sickness during pregnancy can take comfort from their feelings of misery – a new study finds women who experience nausea and vomiting associated with morning sickness were 50 to 75 percent less likely to have a miscarriage. 

It has been known that women who experienced morning sickness during their pregnancies often have less pregnancy loss but little is known about why.  Researchers wanted to see if they could discover if morning sickness is just a side effect of pregnancy or has a specific purpose.

To put this to the tests, 797 women, all at the beginning stage of pregnancy confirmed by a urine test, were evaluated between June 2007 and July 2011.  Out of the number of women enrolled for the study, 188 pregnancies – about 24 percent – ended in a miscarriage.  The rest of the women reported nausea (57 percent) and other women reported both nausea and vomiting (27 percent). 

What was found was that women who reported nausea had a 50 percent reduced likelihood of a miscarriage while women who reported having both nausea and vomiting had a75 percent reduced likelihood.

The results from the study backed up what has previously been known but it did not prove cause and effect. 

It is speculated that morning sickness might prevent some women from doing harmful activities such as smoking or drinking alcohol which would be detrimental to the baby. 

The causes of morning sickness seem to stem from changing hormone levels in women when they become pregnant.  The pregnancy hormone, human chorionic gonadotropin (hCG) may be one that particularly brings on morning sickness.  Cells within the placenta produce the hormone hCG after the egg has been fertilized and implanted in the uterus.  Even though morning sickness can be very unpleasant, it is considered a good indicator of a viable placenta since it is releasing enough hCG hormone causing these symptoms. 

But it is stressed that just because a woman may have no signs of morning sickness, it does not mean or should she assume that something is wrong with the pregnancy.  The researchers pointed out that every pregnancy is different with their own unique outcomes.

Most women get through morning sickness with few complications but roughly about 1 percent of women will have severe nausea and vomiting known as hyperemesis gravidarum (HG) which is considered a serious disorder that may result in significant weight loss, ketonuria, dehydration, nutritional deficiencies, and may require admission to the hospital to restore nutrition and hydration.