Dr Way said that a first pregnancy allows babies to encounter a “hospitable niche” which triggers greater “hospitality” in their mother for future siblings.
In 2012, the Cincinnati team discovered that a first pregnancy makes a woman’s body much less likely to reject a second pregnancy with the same father.
Isn’t nature patriarchal, eh?
A major (overwhelming?) confounding variable. All the mothers I know say that the second pregnancy is easier than the first. By the fourth it’s just a routine. By the seventh I imagine mummy might be getting a bit tired but you’d have to ask Ursula von Leyden about that.
This is all well known isn’t it? My parents were married for 10 years before I arrived and then my sibling followed 2 years after that.
Friends of mine tried for ages for their first and had nearly given up when the eldest arrived. Again, no. 2 came quickly after that and very smoothly despite the woman being in her 40s by that point.
This isn’t news – pre-eclampsia and eclampsia (high blood pressure in pregnancy leading to seizures) is a disease of first children with a particular father. That was taught >20 years ago at medical school, and I doubt it was new knowledge the.
@Gasman, Yes, and Other Things to do with developmental biology.
We just didn’t know the mechanism, nor did we have the techniques to even try and figure it out.
Suspicions, yes. But no way to prove them.
Now we do, and it’s actually quite interesting.
The mother’s immune system is fighting the foreign tissue. Proof incidentally that it’s not her body and not her choice.