Tuesday, July 30, 2013

Treatise on the Diseases of Females: Pregnancy in the 1800s

While looking through some seriously old books, I came across a medical treatise from 1853. Now this would be fascinating on its own, but even better, it's a treatise specifically about the "diseases of females" written by William P. Dewees, M.D.

William Dewees (from Wikipedia)
Having recently been pregnant, I was particularly interested in the 1800s recommendations for pregnancy.

Dewees starts out his chapter on pregnancy by explaining why it is important to scientifically determine whether a woman is pregnant or not. The reasons are essentially as follows:

1. So if the woman needs to be treated for some other disease, she doesn't get prescribed something that would hurt her or the baby if pregnant.
2. Because if she is under trial or awaiting execution, pregnancy might forestall it.
3. If the predicted date of birth might influence the 'character or property' of someone else.

So yes, clearly it is important to know if a woman is pregnant.

So how do you tell in the 1800s when no pee-sticks with plus signs were available? Not surprisingly, the first way is 'she doesn't have her period.' However there is clearly some debate in the field at this time.

Other things can 'suppress the menses' and sometimes a woman can bleed while pregnant.

Dewees spends excessive words and semi-colons defending his position on the subject:

"In declaring that women may menstruate after impregnation, I have no favourite hypothesis to support; nor am I influenced by any affectation or vanity to differ from others; neither do I believe I am more than ordinarily prone to be captivated or misled by the marvellous; for I soberly and honestly believe what I say, and pledge myself for the fidelity of the relation of the cases I adduce in support of my position." *

So you need some other signs of pregnancy other than just not menstruating. Next up: Nausea and Vomiting. Though "far from certain" as a sign of pregnancy, in conjunction with other signs, it is 'added proof'

Another sign is the enlargement of the sebaceous glands (which are on the areolae around the nipple), and the formation of milk. But milk coming in is also not certain:

"I once new a considerable quantity of milk form in the breasts of a lady, who though she had been married a number of years had never been pregnant; but who at this time had been two years separated from her husband. She mentioned the fact of her having milk to a female friend, who from an impression that it augured pregnancy, told it to another friend, as a great secret; and thus, after having enlisted fifteen or twenty to help them keep the secret, it got to the ears of the lady's brother. Her surprise was only equaled by his rage; and, in a paroxysm, he accused his sister, in the most violent and indelicate terms, of incontinency, and menaced her with the most direful vengeance." *

It turns out the lady was not pregnant, but was sick with 'phthisis pulmonalis.'

So finally the surest signs of pregnancy are the enlargement of the uterus and abdomen, and feeling the baby move "quickening".

(also mentioned are the 'pouting of the navel' and the 'spitting of frothy saliva')

*All quotes from Treatise on the Diseases of Females by William P. Dewees

© TheCellularScale

For more on historical pregnancy medicine, see some great posts from Tea in a Teacup

Sunday, July 7, 2013

Male DNA in the Female Brain

When you are pregnant, people like to tell you all sorts of things about yourself.

probably the most complimentary thing I have been compared to.

"you are going to have a boy/girl"
"you are carrying high/low"
"you look like an olive on a toothpick/beached whale"
"you probably have some of your husband's DNA/baby's cells in your brain now."


That last one requires a little more explanation. How could new external foreign cells get into my brain? First of all there is the blood-brain barrier which prevents your own blood cells from getting mixed in with your neurons, and second of all there is the placental barrier that prevents your blood from mixing with the baby's blood.

Neither of these barriers are perfect. Certain drugs and chemicals can cross the blood-brain barrier, and drugs and chemicals that a pregnant woman ingests can cross the placental barrier to get to the baby. But are these barriers so leaky that whole cells can get through?

Apparently they are. Dawe et al., 2007 explains possible ways that this can happen.

The placenta, up close. (Dawe et al,. 2007 Figure 1)
The placenta develops with the fetus, and so it is a hotbed of new growing cells early in pregnancy. It is made up of a combination of cells that contain the mother's DNA and cells that contain the new baby's DNA. However it is not clear exactly how baby cells get transferred to the mom. In the author's words:

"The mechanism by which cells are exchanged across the placental barrier is unclear. Possible explanations include deportation of trophoblasts, microtraumatic rupture of the placental blood channels or that specific cell types are capable of adhesion to the trophoblasts of the walls of the fetal blood channels and migration through the placental barrier created by the trophoblasts." (Dawe et al., 2007)

It is also not clear how these baby cells, once in the mother, could cross the blood-brain barrier. In fact, it is not perfectly clear (as of this 2007 paper) that these cells do get into the mother's brain in humans, though studies have shown fetal DNA-containing cells in the brains of mice.

So in conclusion, if you have ever been pregnant, you probably still have some of that baby's DNA (and consequently some of the baby's father's DNA) in your body. If you were pregnant with a boy, then you probably have Y chromosomes in some of your cells! It even seems that mothers can transfer cells from previous babies into future babies. This means that if you have an older brother or sister, you might have some of their DNA in your body as well.

The next question is: Do these foreign DNA cells have a meaningful impact on your body?

© TheCellularScale

ResearchBlogging.orgDawe GS, Tan XW, & Xiao ZC (2007). Cell migration from baby to mother. Cell adhesion & migration, 1 (1), 19-27 PMID: 19262088