I had an ultrasound at 34w and have an AFI of 30cm. My OB didn't seem too concerned and had me get blood drawn to check my sugars over 3 months, but that came back "excellent". So there doesn't seem to be an apparent cause (which I know is common), but she did mention something I'm not sure I'm comfortable with regarding delivery. She said a lot of times they want to do a slow release of the waters to avoid placental abruption. I understand that abruption is a concern with this, but I have other concerns.

1) In my last labor (my first labor, 2nd pregnancy, VBAC) I didn't dialate until labor, so they won't be able to do an amniotomy with no dialation.

2) The baby didn't engage until I was almost pushing. I know this greatly increases risk of prolapsed cord.

3) I delivered at 42 weeks last time. I know there is a chance of going earlier with poly, and I have had BH contractions, which I did not in my last pregnancy.

4) I REALLY want and plan to have a natural, low intervention birth and I planned to do that with my waters intact. It also seems like a good idea to have CFM if this is the plan, which I know comes with a whole other set of pros and cons.

I really like my OB (she has delivered twice drug free) and she supports my birth plan. We do plan to keep an eye on the fluid and I know a lot could change in another few weeks even. I just want to know if this is really the best course of action for excessive fluid.

Here's what you need in order to make an informed choice:

• An explanation in plain English of what the procedure involves: How does one do a slow release of the amniotic fluid? The common procedure is to snag the membranes with an amnihook (it looks like a crochet hook with a little tooth under the curved tip). My experience seeing this done back in the day when I was a doula was that that rupturing membranes was followed by a gush rather like breaking a water balloon.
• The potential benefits of what your ob is proposing: You have this piece already, i.e. to prevent the placenta from detaching prematurely. What is missing, though, is how likely is this to happen. One in ten? One in a thousand? One in ten thousand? Without this, you can't decide whether it is worth running the risks of rupturing membranes.
• The potential harms of rupturing membranes: As you say, with a high head and lots of amniotic fluid, you run an increased risk of cord prolapse. How likely is that to happen? Any way to prevent it? Apart from issues of rupturing membranes with a high head, the procedure itself has risks. Some studies find more episodes of abnormal fetal heart rate, and a systematic review (a kind of study of studies) of trials in which women were assigned to early rupture of membranes or not reported a trend toward more cesareans, although I think this will be much less of an issue for you because you have had a vaginal birth before. It also sounds as if your ob is talking about inducing labor to prevent spontaneous rupture at home. If that is so, you will want to weigh the trade-offs of induction versus the odds of membranes rupturing at home and the possible consequences of that. For example, inducing labor with pharmacologic agents can increase the likelihood of having the uterine scar give way, although it is moderated by whether the cervix is ready to labor and whether the woman has had prior vaginal births.
• What other medical interventions might or would become necessary as a result of this one and the pros and cons of those.
• What alternatives you have, including doing nothing.
• The benefits and harms of your alternatives.

As you can see, and doubtless, already know, your decision isn't a straightforward one. It requires weighing a number of factors relevant to your individual case and taking into account parameters that may change over time. Maybe the best thing would be not to make a firm decision one way or the other now but to discuss what makes the most sense under a set of likely possible scenarios.

-- Henci