The truth of being able to predict the gender of your baby by the severity of your morning sickness is veiled in the mystical origins of most old wives’ tales. However, this pregnancy myth has some scientific evidence to support the women who continue to believe in it.
The Old Wives’ Tale
According to this old wives’ tale, if you have severe morning sickness, you are more likely to deliver a girl. Like other pregnancy myths, this prediction has uncertain origins. However, women who swear by it or are looking for scientific proof of this passed-down belief keep it alive through ongoing Internet discussions.
The Scientific Evidence
A few studies found that women who had severe morning sickness (hyperemesis gravidarum) had a 27 to 80 percent greater chance of having a girl than a boy. The following is a sample of these studies since 1999:
- A Swedish study reported in the British journal, Lancet in 1999, found that women with hyperemesis gravidarum were more likely to deliver female offspring than women who did not have severe morning sickness.
- A Danish study, summarized in a letter to Lancet in 2000, showed that there were more girls born to women admitted to hospital for hyperemesis than in the general population. The birth gender ratio was 1.0:0.87 girls to boys, compared to the usual average of 1.0:1.05 girls to boys in the general population.
- A Boston University study published in the journalEpidemiology in 2001 showed that women with hyperemesis delivered more girls than women without hyperemesis, regardless of whether they had to be hospitalized or not.
- A study from Washington State of pregnant women, hospitalized between 1987-1996 for hyperemesis in the first trimester, was reported in 2004 in the journal An International Journal of Obstetrics and Gynaecology. Compared to women not hospitalized for hyperemesis, these women were 50 percent more likely to deliver girls than boys and had a birth gender ratio of 1.5:1.0 girls to boys. Women who were hospitalized three days or more had an 80 percent (1.8:1.0) greater chance of having a girl than a boy.
- Dutch researchers published another study in the same BJOG journal in 2011. This was a statistical analysis of several previously published studies by which they found that women with hyperemesis overall had a 27 percent (1.27:1.0) greater likelihood of having a girl than a boy.
There are no studies comparing women with milder symptoms of morning sickness to those without morning sickness.
Possible Explanation Offered
Women who are pregnant with girls are thought to have a higher level of the pregnancy hormone human chorionic gonadotropin (HCG). Some researchers suppose that the higher HCG and/or the higher estrogen levels produced by female fetuses account for the greater severity of hyperemesis in those women.
Although these studies show some support for the myth that women with morning sickness are more likely to have a girl, the reality is that the rest of the symptomatic women had boys. Therefore, this old wives’ tale is not a dependable way to predict the gender of your baby. Go the conventional route and get an ultrasound if you are yearning to know, or wait for the delight of the surprise at birth.