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Pregnant women with heart disease are more likely to give birth to girls than boys, according to a new study from Iran.
The study involved 200 pregnant women diagnosed with heart disease who were referred to a heart center for delivery. Of the 216 children born to these women, 75 percent were girls.
The number of boys born in any human population should be similar to the number of girls born, but the boy-to-girl ratio in any given country can vary depending on practices of sex selection. In Iran, about 105 boys are born for every 100 girls, according to the Central Intelligence Agency. In the heart disease study, 32 boys were born for every 100 girls.
The reason for the skewed sex ratio among babies born to women with heart disease is not known. The researchers, from Tabriz University in Iran, said they hope their study spurs additional research into the link. The study was presented April 20 at the World Congress of Cardiology in Dubai.
"Chromosomes in a man's sperm are responsible for the sex of a baby," Dr. Kathryn Taubert, chief science officer at the World Heart Federation, said in a statement. "But this study does suggest that there may be a relationship between the health status of the mother and the sex of the babies that she is able to carry to full-term," said Taubert, who was not involved in the study.
The average age of women in the study was 29. Most women (64 percent) had a form of heart disease than involves problems with the heart valve. Nineteen percent had dilated cardiomyopathy, a condition in which the heart becomes weakened and enlarged, and is not able to pump blood efficiently. Fourteen percent had a problem with their heart's structure and function that was present since birth.
Sperm carry either an X or Y chromosome, while eggs carry only an X chromosome. When a sperm cell with an X chromosome unites with an egg, a female born. When a sperm with a Y chromosome unites with an egg, a male is born.
A study published last month suggested women are more likely to give birth to girls during a famine. Those researchers speculated this might be because, in a famine, male sperm carrying a Y chromosome were less likely to fertilize eggs. It could also be that, during famine, fetuses carrying a Y chromosome were more likely to be miscarried, the researchers said.
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Bah, my mom has had heart problems her whole life and gave birth to two boys. Yet another report that appears to not know what its talking about.
One exception does not invalidate the general trend. It's the difference between a personal anecdote and epidemiological research (this article reports on the latter). Just as some people who smoke will never get lung cancer, and some people will be trapped in their car by their seatbelt during an accident, and some babies whose mothers drink during pregnancy will not have Fetal Alcohol Syndrome. Your personal experiences may not be typical. That's why scientists do research on larger samples. And a sample of 200 pregnant women with heart trouble have mostly girls is statistically significant, even though some of these women had sons.
Well, considering the male is the one "responsible" for passing on the chromosome that determines sex, I find this study a little weird and pointless. Why was someone even paid to study this when there is no possible way that any medical condition in a woman could determine what sex a baby was?
I'm not sure if you read the entire article or not. However, at the every end of the article is this:
The findings of this study also are reflected in studies in areas with famine (also mentioned in the article).
Essentially, male fetuses are more likely to be spontaneously aborted (miscarried) by a mother in poorer health than a female fetus.
The X or Y chromosome in the male sperm at the time of fertilization determines the sex of the offspring. Biology 101. Stupid, stupid article.
Salemone: Perhaps you need to read the entire article? It doesn't say anything contrary to what you stated.
From the article:
This study basically agrees with a similar study looking at famine (also mentioned in the article).
Basically, the article (and study) is saying that a male fetus is more likely to be spontaneously aborted (miscarried) when the mother is in poor health than a female fetus. This results in women in poorer health (such as heart disease as in this study, or health problems associated with famine as seen in the other study) giving birth to more female babies.
yes but you assume every conceptus is carried to term- which it is not. more often than not a woman miscarries before she even knows she was pregnant
aggrevatedofficeworker: No, I'm not. The study simply indicated in pregnant women who have heart disease, there are more female fetuses carried to term than male fetuses. This is the same findings seen with studies on famine. The researchers stated that it appears that more male fetuses are lost when the mothers have these conditions than female fetuses. This finding also seems to go along with other findings that when a fetus has certain health problems, a male fetus is more likely to die or have long lasting complications than a female fetus. Really, it appears to be more of something (though what that something is, is unknown) makes female fetuses better able to withstand certain prenatal stresses.
Because girls are heartbreakers?
So basically the two studies seem to indicate that in most cases it takes a healthy strong woman to carry boys to term. I wonder how many of those boys that make it to term have some kind of problem. This interests me.
Well, just look at Morlack.
A sample size of 200 is enough to prove a point? I have no doubt 200 women with heart problems who gave birth to boys could be found just as easily.
Regardless, what does this so called study actually prove? How does it help anyone?
JCA, And if they did some hormone analysis they might have enough information to form a hypothesis! Around the world scientific/medical research is a sham!
Yeah, a sample size of 216 really tells you nothing. Probability theory and statistics would provide useful information in a case like this only with a huge sample size.
Only 200 women? And really so what if it's true?
But it may be simply lifestyle differences between sicker women and healthier women. Positioning, timing, age, frequency...it could relate to how you did it, when you did it and how often, the men sicker women tend to partner with could be shooting more female-producing sperm, etc. I mean if you have heart trouble you aren't going to be doing certain things...perhaps in those women those things tended toward the success and as someone suggested, the heartier females made it versus less robust males. So many variables.....
Gonna take a completely unscientific shot in the dark at this one.
Perhaps, for her own survival, a sickly mother would be more likely to survive if she gives birth to a girl.
Bear with me now. Suppose the woman's body knows that she is sick. Our bodies respond to illnesses all the time without us even being aware of it. Now, continuing with that thought, traditionally throughout time a daughter is more likely to care for an ailing mother.
Is it possible that if a woman is going to have a baby, and will need that baby to care for her later in her life, that her body will attempt to give birth to a female (i.e. self-aborting males) so that she has a better chance of living longer.
I know, a wild shot in the dark. Just throwing it out there.
The most logical explanation for the mechanism of how this might work is that while, on average, more males are conceived than females (105 to 100, as the article states), male fetuses are more physiologically vulnerable to the mother's inadequate heart action. Therefore, male fetuses miscarry more often than female fetuses. This is simply another confirmation of what many studies have shown -- that regardless of the cause of the problem, males are more likely to suffer and die. At every age bracket from conception to old age, males die more often than females. Also, many developmental problems affect more males than females, because the females are better able to cope with the causes, while the males are more likely to be affected to the point where they show symptoms. These include: autism spectrum disorders, ADD and ADHD, cognitive problems from lead poisoning, fetal alcohol syndrome, criminal behavior in adulthood as a result of exposure to nicotine during gestation, and the list goes on and on and on. Interestingly, in some cases where a genetic problem affects both male and female fetuses in equal numbers, the males almost always miscarry, leaving mostly females to exhibit the problem, such as Rett's Syndrome.
Male fetuses are more fragile and boys who are born prematurely tend to do worse. I think the idea here is that women who are in poor health are less likely to be able to carry the already more fragile male fetus to term.
The Maternal-Fetal medicine specialist I saw jokingly called my son a wimpy white boy before he was born. White males tend to be the least hearty newborns and have the highest percentage of issues.
It's well known that men are more vulnerable to death during every stage of live, from fetus to old age. This study confirms that idea, and helps us to understand it more.
The idea that the gender odds are 50/50 for every pregnant woman is a very simplistic and outdated view.
I wonder if they took into consideration whether the family history is stronger with girls than with boys. Our family has mostly girls and not one of my 4 sisters and 2 brothers had or have heart disease. Our children have 4 girls and 5 boys. Only one boy and one girl born with a heart defect but parents of these kids do not have one. It is such a limited study and cannot reflect the true results IMO
What better place than Iran to find women under stress?
...considering that Afghanistan has no investigative medical infrastructure and Saudi Arabia wouldn't waste money on women.
Ha! I have heart disease my whole live and ended up with 3 boys...boy #2 & #3 were suppose to be girls. This article really doesn't have much validity and doesn't accurately reflect the general population.
Female fetuses are stronger, I've read, and more likely to survive adversity visted upon them by their mother's bodies. Born into adversity, unless starved (as they do in India), a female will be more likely to survive, also.
Slight digression: It is very interesting the various ways different cultures find to punish their females for their uteruses which is why I'm pro-family planning and pro making males pay half for birth control if we in the United States simply can't make ourselves cover birth control with our already high priced Healthcare Insurance... of course, helping to finance things like Viagara through Healthcare Insurance should also be disbanded. Right? Anyway, I live in a culture that not only punishes those of us with uteruses, my culture also punishes Stay At Home Parents and anyone who cares for children...
What are we going to do!!!!There are more women than men.Let's test all women.It'd only be a coupla billion,if we limit testing to actual citizens that is.