The study finds that women who experience more stress during the conception period are twice as likely to give birth to a GIRL
- Experts monitored stress levels in 108 women from pre-conception to birth
- They did this by measuring the stress hormone cortisol in hair follicles
- Women who have gone to childbirth have higher cortisol levels around conception
- The results confirm how fetuses are vulnerable to the impact of maternal stress
A study found that women are twice as likely to give birth to a girl if they experience more stress during the time of conception.
Researchers from Spain recorded the levels of the stress hormone cortisol in the hair of 108 women from about nine of their pregnancies until delivery.
Each hair measurement covered the cortisol levels during the preceding three months, meaning that the first one taken covered the period before and after conception.
The findings confirm that fetuses are vulnerable to the effects of maternal stress and that such individuals may play a key role in their development.
A study found that women are twice as likely to give birth to a girl if they experience more stress during the time of conception. In the photo: a newborn baby girl
“The results we found were astonishing,” said author and psychologist María Isabel Peralta-Ramírez of the University of Granada.
“They showed that the women who gave birth to girls offered higher concentrations of hair cortisol in the weeks before, during and after the conception period than those who had boys.”
The findings contribute to increasing evidence that stress experienced by mothers during the time of conception and during pregnancy can have an impact on the nature of pregnancy, birth and even neural development of infants.
“Our research group has shown in numerous publications how psychological stress in the mother generates a greater number of psychopathological symptoms during pregnancy,” said Professor Peralta-Ramírez.
Stress, she added, can also cause ‘postpartum depression, an increased likelihood of assisted delivery, an increase in lactation time, or an inferior neurodevelopment of the baby six months after birth’.
The study explained that this study is one of the few that has shown the impact of stress during and even before conception – rather than simply the psychological stress experienced during pregnancy.
The findings contribute to increasing evidence that stress experienced by mothers during the time of conception and during pregnancy can have an impact on the nature of pregnancy, birth and even neural development of infants. In the photo: a young woman experiences tension
According to the researchers, it is possible that their findings could be explained by the body’s ‘stress system’ that changes the concentration of sex hormones during conception, but how exactly this would work is not clear.
There is evidence that testosterone can influence the determination of a baby’s gender – and the higher the levels of prenatal stress, the higher the levels of female testosterone.
Alternatively, the team explained, there is also evidence that sperm carrying the X chromosome – and thus the ability to conceive a female fetus – are better able to move through the cervical mucus in conditions of adversity.
“There are other possible hypotheses that try to explain this phenomenon,” Professor Peralta-Ramírez explained.
“One of the strongest theories is the idea that during the first weeks of pregnancy there are more terminations of male fetuses on medical grounds in situations of severe maternal stress,” she added.
“It is said that, in the light of the design of these studies, it is recommended that the results be confirmed in greater depth.”
The full findings of the study were published in the Journal of Developmental Origins of Health and Disease.