posted
Why is a healthy pregnant woman considered any more at risk for the flu (or perhaps from complications) than any other healthy person? I don't know what statistics there may be to back this, but myself, most of my friends have found they got sick LESS often during prenancy.
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posted
My understanding is that it isn't that the mother is at greater risk, it's that the impact of the flu on a developing fetus can be a Very Bad Thing.
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posted
Since an embryo doesn't carry the same genes, a woman's body must dampen down the strength of its immune response. Without such dampening, the potential mother's immune system would detect the embryo's phenotype as different from the body it is fine-tuned to protect, and recognize the embryonic cells as foreign. Then the woman's body would treat the embryo as it would any other invader: ie kill it, then either isolate/encyst it or deconstruct&remove it. While this dampening&detuning of the woman's immune response does allow the survival of the fetus, it also makes the woman more susceptable to infections.
posted
aspectre, where did you get that information from? Because it just ain't so! The placenta is a marvelous organ, and it ensures that the mother's blood and the blood of the developing fetus NEVER mix. Thus, unless there is some (fairly severe) trauma, there is little chance of the mother's immune system "seeing" any fetal proteins -- until delivery, when some amount of blood mixing does occur. (And this does cause occasional complications, but fairly rarely. The real risk is that the mother will develop antibodies (such as to the Rh factor) which present a danger to FUTURE fetuses.)
Pregnant women are NOT immuno-suppressed. However, some women find themselves more susceptible to infection (since their bodies are working harder than usual). Similarly, while some pregnant women find relief from their allergies, a smaller percentage experience increased allergic symptoms. (Guess which group I fall into? )
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posted
I've found that pregnancy is a mixed bag infection wise. Some bugs I'll get and keep 3 times as long as the rest of the family, others go through everyone but me. Though I kind of favor aspectre's explanation. I thought it was a major cause of miscarriage. Keep in mind that the placenta isn't in place for the first 3 months.
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quote: The main reason is that you don't want to get the flu while you are pregnant, since it will put you at higher risk of flu complications, both for yourself and your baby.
Also, having a flu shot will decrease the chances your new baby will get sick once he or she is born. Afterall, without a flu shot, you can get sick with the flu and then pass the infection to your new baby.
It will also be hard to care for your baby if you get sick with the flu, which can cause fever, muscle aches, headache, severe malaise, nonproductive cough, sore throat, and runny nose, with some symptoms lingering for over two weeks.
For this reason, you should also consider getting a flu shot for other household contacts of yourself and your new baby. Remember that anyone over 6 months of age can get a flu shot each year.
Getting a flu shot during pregnancy can also help keep your baby healthy by transfering influenza vaccine-specific antibodies to them, which can last for 'for at least 2 months.'1 These antibodies should be able to help your new baby from getting the flu.
posted
The worry I have is for people going across the border to get vaccine. There is just too much demand to trust that some unscrupulous person isn't going to pass off junk as the real deal. But maybe I'm paranoid.
Though the people who complain about making old people stand in line for hours and hours... if people aren't well enough to leave their home, they are less likely to be exposed to flu, right?
quote:The concept that pregnancy is an immunosuppressive state permitting the fetal allograft to implant and grow has held center stage for years. In fact the placenta is not a cell-impermeable barrier preventing exposure of fetal alloantigens to maternal T-cells...rather, maternal and fetal cells are reciprocally transported across the placenta during gestation. Indeed whole cells of fetal origin and fetal DNA have immediate access to maternal venous blood, where they can persist long after delivery.
For an HTML version, [URL=http://66.102.7.104/search?q=cache:bOHx9ciF4iYJ:listproc.ucdavis.edu/class/200403/mmi209sp-s04/att-0000/02-immune_effect_of_pregn.pdf+pregnancy+suppresses+the+immune+response& hl=en]http://66.102.7.104/search?q=cache:bOHx9ciF4iYJ:listproc.ucdavis.edu/class/200403/mmi209sp-s04/att-0000/02-immune_effect_of_pregn.pdf+pregnancy+suppresses+the+immune+response &hl=en[/URL]
posted
Gives a new meaning to my old joke about the Bryan Adams line "When you can see your unborn children in her eyes..."
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quote: Placenta formation begins as early as day 24 of what would have been the menstrual cycle
That is, about 40 days post conception.
In any case, before the placenta forms, there is NO interaction between fetal tissues and maternal tissues. There are six membranes separating the fetus from the mother (three fetal, three maternal). Parts of these form the placenta and umbilicus. (about half-way down)
aspectre, the source you cited is primarily speaking in hypotheses. However, what they did actually measure indicates that while some immune cells decrease during pregnancy, others increase. Here is a press release from the same study. I did find other research/studies showing that there are significant immune changes during pregnancy -- far more significant than I had realized. However, there seems to be contradictory information on whether infection rates in pregnant women are higher. Especially in the later trimesters, which is when the flu shot should be administered.
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quote:About 6 days after fertilization, the embryo is shaped like a sphere. The surface of the sphere is made up of a layer of specialized cells called the trophoblast. At this phase of development, the embryo is called the blastocyst. The trophoblast later gives rise to the cells that will form the fetus' part of the placenta. (The placenta is made up of both maternal and fetal tissues.) The trophoblast is coated with a protein known as L-selectin. The wall of the uterus is coated with carbohydrate molecules. The researchers believe that as the blastocyst travels along the uterine wall, L-selectin on its surface binds to the carbohydrates on the uterine wall, until the blastocyst gradually slows to a complete stop. After this happens, the cells that later become the fetus' contribution to the placenta develop. The placental tissue from the fetus then invades the uterine wall by sending finger-like extensions into it. These projections make contact with the maternal blood supply, becoming the pipeline through which the fetus derives nutrients and oxygen, and rids itself of carbon dioxide and wastes.
quote:Invasion of these cells into maternal blood vessels causes blood to leak into the space between cells, forming lacunae (lakes), which become the intervillous space. The fetus derives nourishment from the lacunae. Initially, the placenta surrounds the blastocyst, transmitting nutrients and discharging wastes directly across cell membranes. As early as day 11 or 12, villi begin to form on the chorionic surface; they branch and rebranch in a complicated treelike arrangement around the chorionic surface. Villous transfer from maternal blood to fetal blood begins when fetal vessels appear within the placenta at day 19.
In other words, by day twelve, the interaction between the embryo and the uterine wall is already beginning to alter the woman's immune system. The trophoblastic cells are damaging the maternal tissue, yet normal immune response to foreign material -- tagging, isolation and/or destruction&removal, and repair -- does not occur.
posted
There are many anatomic and physiologic changes in the lung functioning of a pregnant woman, too. Emedicine has a great article on this, Pulmonary Disease in the Pregnant Patient. For example, there is increased mucus secretion and decreased deep breaths (the chest gets squashed up by the increasing abdomen), so you are more at risk for developing a bacterial pneumonia in all that stagnant, juicy stuff sitting at the bottom of the lungs.
I don't know the definitive answer to exactly what happens with regards to a pregnant woman's immunology, but we do know that many women with autoimmune-associated diseases can have a brief decrease in or reprieve from symptoms (e.g., rheumatoid arthritis, lupus, etc), so the immune system does seem to be downregulated somewhat.
As regards to what the virus itself does to the developing fetus, I've seen theories but little substantive evidence that it is directly harmful. However, this is certainly an area of some controversy.
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posted
What I am getting from all this is there are lots of hypothoses, but no definitive answers.It does seem to me that unless the mother has a sustained high fever, there would be no direct harm to the fetus.
I suspect what I 'm getting over may be the flu, which my husband seems to be getting but the kids have never caught. So theoretically we shoukd be safe for the rest of the season
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As Noeman pointed out, a flu is more dangerous to an embryo, a fetus, a baby than to the (potential) mother. Especially the fever.
Having one flu won't protect you from catching others.
And while the general public appears to use 'guess', 'conjecture', 'hypothesis', and 'theory' as interchangeable words, they have distinct meanings to professionals.
Mostly just bumping this up to the top, hoping someone will add to the above. Otherwise, be back later to explain in more detail, maybe.
posted
I would be more worried about the fever involved with flu in the pregnant woman and her fetus. When pregnant, a woman should not go in a hot tub because it raises the core body temperature too much and this becomes dangerous to the baby.
My youngest sister is deaf because her biological mother got a virus, most likely rubella, while pregnant. Her type of deafness, discovered when she was 2 days old, shows the pattern of her having had a high fever while in utero. Often the mother may feel only mildly sick while such damage was being done. My sister is lucky. She could have also suffered brain damage and blindness.
What about bacterial infections? What are the risks of those compared to viral infections for the fetus?
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posted
Amka, are you sure the deafness was considered to be caused by a high fever and not the rubella virus itself? Rubella is one of the "ToRCH" infections -- that is, it can pass through the placenta, and a known complication of being exposed to rubella in utero is congenital deafness.
I can't find an association between gestational high fever and deafness (although there are other congenital defects associated with very high fevers in the mother).
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posted
You know, I think the proposal that the immune system is suppressed to such a degree that the mother is unable to mount an attack on the fetus is pretty far fetched. From my experience, pregnant women don't seem to get sick nearly often enough for that to be the case. Plus, it isn't in the mother's interest to be getting sick a whole lot more while she's carrying a child. The body tends to be much more elegant than that.
I'm not disputing that there seems to be some suppression, only that there's likely much more to the story. I happen to like the fairly recent hypothesis that says that antibodies formed in the uterus coat the fetus and effectively screen it from the things in the mother's body that would tag it as "not self."
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Boon
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posted
Anecdotal evidence to follow...
I got the flu in about the fifth month of each of my first two pregnancies.
The muscle spasms caused by the near-continuous vomiting caused me to have contractions. The contractions then upset my stomach, causing more vomiting. Early, full-blown labor followed.
Anti-nausea suppositories and shots to stop the contractions, and a couple of days in the hospital on an IV rehydration schedule stopped the bad stuff.
But a simple flu shot would have been much, much cheaper and less...painful. Wish I'd known then what I know now...
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Boon, I thought flu was an upper respitory thing, not intestinal? I was told by my HCP there is no such thing as "stomach flu" and if you're vomiting you have another bug altogether.
I'm sorry to hear you went through that though.
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posted
I might have been wrong about exactly why the virus caused her deafness. I just connected the two: should not get your core temperature above 101 when pregnant + baby gets virus with baby gets fever that causes the problem.
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Boon
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posted
Romany,
It seems you are correct in that nausea and vomiting are rarely caused by the flu in adults. However, every single flippin' time I've ever had the flu, it's accompanied by extreme nausea and vomiting during the first couple of days. And it does cause intestinal upset in some children.
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posted
Sort of a different question about the flu. If the H5N1 strain is so deadly and may become transmissible in the future, why can't we vaccinate people against it now? If we know it's potentially dangerous, shouldn't we make sure that most of the population is immune to viruses with these surface proteins?
Posts: 3546 | Registered: Jul 2002
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posted
An interesting article on how endogenous helper viruses may aid mothers in implantation and maintaining pregnancy, and in fighting off harmful viruses during pregnancy.
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