Tag Archives: pregnancy

Covidpocalypse Now: an update

Covid, Health and Medicine, , ,

Most of the Covid news is about vaccines.

A second vaccine has passed the final non-red tape hurdle in the US, and will likely be authorized by the end of the week. Six million doses will be distributed, probably over the weekend or early in the week, to over 3,000 locations.

There is argument and discussion going on as to the lower age limit on the vaccines. So far everything seems authorized for 18 year olds and older. It will probably be a serious mistake if that isn’t adjusted very soon. Now, the kids who transmit the disease that kill grandma are anonymous. Once they are the main carriers, they will not be, and a spotty subgroup of an entire generation will be scarred. At least, we’ll be given by fate the name for that generation. The Marys (for Typhoid Mary).

Let’s talk about Pregnant and lactating women for a minute. There have been no systematic trials pertaining to pregnant women, so the FDA advice is vague. They say, “you decide.” The following are supportable facts:

1) There is evidence, subject to revision because it is not the focus of any systematic experimental study, that pregnant women are somewhat protected from getting Covid-19, but not to anywhere near the degree that they can flout caution.

2) There is evidence, again subject to revision, that when pregnant women do get Covid-19, they have a number of worse outcomes than other people of similar age. They may get sicker, and there is a possible risk of preterm birth.

3) Non-live vaccines are generally considered safe for pregnant women.

To manufacturers and health care providers, this may be more a mater of blame and liability than anything else. Of all the people who get the vaccine, some are going to get sick or die randomly even if the vaccine never causes an actual problem, and someone is going to sue somebody over something. The chance of such a suit winning probably goes up if the plaintiff is a pregnant woman or her survivors, or if a baby is born with a problem etc. etc. So, by saying “you decide” we just get on with it, is probably the thinking.

VERY IMPORTANT: We humans have a lot of misconceptions about immunity and pregnancy. A common falsehood is that immunity of the mother is passed on to the offspring. This is not true. Also, an in utero fetus does not get vaccinated when the mother gets vaccinated. A lot of people believe these things happen but they do not.

What does happen is that the mother’s immune products, if she’s got them, circulate in the fetus, and may even be found in the newborn for a while. But an infant does not have much of a functioning adaptive immune system, so there can be no development of long term immunity, and the magical immunity stuff we have spent so much time talking about can’t be passed on.

During lactation, some of this humeral immunity of the mother will be shared with the offspring via breast feeding. This, of course, is also temporary.

It has been a while since I’ve done a literature search on this, but last time I looked there were no studies that really examined how effective any of this passive immunity is. Our cultural love of breastfeeding, and rhetoric from pro-breast feeding organizations, have led many people to believe that mother to infant immunity (i.e. through breastfeeding and esp the passing on of colostrum) is powerful and highly effective. We don’t really know this.

Doses:

In the US right now 2.9 million Pfizer doses (with second doses already accounted for) have been shipped. Moderna will ship over 5 million doses right away. According to Health and Human Services (a Trump Crime Family Joint) there will be enough doses to vaccinate everybody in the US by the end of June 2021. We await the replacement of the Deplorables with Biden appointees to confirm (or deny) that.

Can you pass Covid-19 on if you are vaccinated?

Nobody knows yet, but there is not really a useful “yes” or “no” answer to this. Here’s the story: What matters is the R0 value of the disease, right? How many people will get infected down the road if a particular individual is infected. More realistically, sort of, imagine a population of 1 million people, and 1,000 people freshly infected show up and there are no precautions taken. If that disease is Covid and the 1 million are not vaccinated, the next “generation” of infection will see more than 1,000 people infected, and the next generation, more than that, etc. as a wave of the disease spreads across the populations. SO, maybe, 1,000 gets you 1800, and that gets you 2500, and that gets you 4,800, and so on.

If most everybody is vaccinated, the whole point is that the chance of the virus being able to reproduce in you at all is lower, the time frame and intensity of that reproduction is shorted or lowered. Maybe to zero, but even if not, the R0 value is significantly lowered.

So, in the above scenario, with the population mainly vaccinated, 1,000 infected people gets you maybe 100 (max, that would b a lot) which gets you 10, which gets you zero, and Bob’s your uncle.

How to choose the sex of your baby.

Evolutionary Biology, , , ,

In order to make such a momentous decision, I insist that you learn the very interesting evolutionary biology behind it.

Start with this paragraph:

But for modern medical science, a baby’s sex would remain unknown until birth. But many mothers today know long beforehand whether a baby will be male or female. Routine ultrasound scans reveal fetal genitals a third of the way through pregnancy, and genetic tests identify sex even earlier. Yet basic questions remain. Is a baby’s sex like coin tossing, or can the male:female ratio be skewed? If sex bias occurs, does it happen through sperm sorting before fertilization or mortality differences in the womb after conception?

Then, CLICK HERE to read the rest of the story, by Robert Martin, expert on such things.

Your chance of getting pregnant if raped…

Uncategorized, , , ,

… goes down, compared to other forms of insemination, because “the female body has ways to shut that down.” That’s according to Missouri Congressman Todd Akin. But this only works, according to him, if the rape is “legitimate.” From this we can easily develop a sort of Witch Hunt method to determine if a woman accusing a man of rape was actually, “legitimately” raped or if she’s faking it. If she becomes pregnant from the rape, the rape did not happen.

Is this clear?

OK, now that we have that straight, allow me to bring out this one piece of data I thought I’d never have use of. It is a very limited piece of data, not very useful for a large number of reasons. The question at hand can be divided into two parts: 1) What is the chance of a given intromissive internally insemnating sexual event leading to a pregnancy in a woman not on birth control of average fecundity? Then, 2) Does this probability go down, as the good Congresman claims, or does it stay the same.

The answer to the first question is that it is not terribly high. We are not a one-copulation=one baby species. It takes a bunch of tangos to turn out a tyke, on average (but statistics is NOT a birth control method!). As to the second question, it turns out that according to certain data it actually goes up. It is reasonable to suggest that the chance of a single copulation leading to pregnancy if that copulation is rape is about double the overall average. Maybe.

This has been discussed by Thornhill and Palmer, authors of the controversial book “A Natural History of Rape: Biological Bases of Sexual Coercion” and subsequent to the storm of debate that arose from that it has been looked at more carefully and a little bit verified (see this).

I can very easily suggest explanations for this and I can also cast more doubt on the studies. First, the doubt. We have no idea what the actual relationship between having sex and having babies is. One would think we would know, but we don’t. Sure, sex leads to babies and all that, but how many sperm, or how many ejaculations, or whatever, does it take before a single sperm is allowed access to the ovum leading to a pregnancy? Scientifically speaking the research needed to answer this question has not been done. There are no controlled studies in which a sufficient sample of subjects across a range of fertilities (and varying in other appropriate factors) repeatedly have sex with everything carefully measured and controlled. Not one study has done this. I don’t expect there to be one any time soon. Our estimates of fecundity are based on reported data, vague estimates, and a lot of thumb sucking. So, when we have a couple of rape-related studies that show a higher pregnancy rate than background, unless it was a lot higher, we would need to take that with a grain of salt.

But if there really is a higher chance of pregnancy resulting from rape, this still may not mean much. There are a number of reasons this could happen, some of which are discussed in the above mentioned book. One very distinct possibility is that rapists are selecting victims somehow, perhaps with their Darwinian wiles, as it were, or perhaps for purely random reasons, who are slightly more fecund than the larger sample from which the baseline statistic is calculated. In any case, the difference is not large.

But, there it is also not lower. The chance of pregnancy from what the Good Congressman calls “legitimate rape” … a term that will surely live in infamy … is not lower. It might be higher. But it is not lower. The man is an ignorant fool. He is wrong.

Here he is being wrong:

Hattip Kent Jones.

Added: Here’s an idea, ask that this dude be relieved of his duties on the House Science and Technology Committee. Which, amazingly, he is on.