I have a history of preeclampsia. If I have another child with the same partner, does that affect my risk? Or, I have a new partner. If I have a child with him, how does that affect my risk?
It depends. We know preeclampsia is multi-causal, so there is no one answer that fits all cases. Here are several scenarios:
Most women only get preeclampsia once and go on to have normal pregnancies. For the more common mild-at-term cases, one theory is that the mother's body just does not "know" how to do pregnancy first time around, but figures it out for the next one. This would hold true with either the same or a different partner. *IF* this is the reason you got preeclampsia, you are likely to be fine no matter the father.
Another possibility is that the mother's immune system overreacts to the foreign DNA from the father the first time, which prevents the placenta from implanting properly and leads to preeclampsia. Second time she has become familiar with his DNA and accepts it more easily. A new partner introduces new, unfamiliar DNA, which can trigger an immune response just like the first pregnancy with the previous partner. *IF* this is the reason you got preeclampsia, changing partners would raise your risk while staying with the previous partner would lower it.
Yet another possibility is the Dangerous Partner theory. The placenta is half mother and half father. Your genes work together to build it. It is thought some men code for aggressive placentas, which would result in preeclampsia and other complications no matter who the mother is. Some couples have genes that do not work well together in placenta building. They might have preeclampsia together every time, but would each do better with a different, more genetically compatible partner. *IF* this is the reason you got preeclampsia, a new partner could actually lower your risk while staying with the same one would raise it.
And some women would have preeclampsia no matter who the father is, because they have some other underlying condition or trigger going on. *IF* this is the reason you got preeclampsia, your risk is the same regardless.
It is difficult, often impossible, to figure out exactly which scenarios apply to which couples. If you have had preeclampsia once, you should be considered high risk and monitored closely in a future pregnancy, no matter who the father is. Being high risk does not mean you will definitely get it again, only that they will watch you closely just in case. Close monitoring will make sure you and baby have the best chance possible.