Too quick to fast?

(No, you can't have this on Tisha B'Av, unless Moshiach comes!)

Every year before the big fasts - Tisha B'Av and Yom Kippur - I get the phone calls from women in the community. 'I'm breastfeeding - should I fast?'  So I give them an answer and advise them to take it to their Rabbi. And maybe they listen and maybe they don't. 

The ones that don't call me, I don't hear from most of them, obviously. But I hear from some of them, a day or two later. With mastitis. With supply crash. In one case, with grossly abnormal liver function, and liver pain, as a result of vomiting and dehydration. 

Now I will just come out and say that I think that breastfeeding women should not fast. Not at any stage. I will also say that I don't think that pregnant women should fast either. I don't know how much science is in this, but it seems that fasting can bring on premature labour. The maternity hospitals in Israel have a rush of patients after YK every year, so maybe there is a study out there. 

I know that 9Av and YK are different but fasting is fasting and dehydration is dehydration. You can also talk about how it's different if the mother is Yoledes (recently gave birth), or if the baby is under 6 months or if he is fully dependent on breast milk yada yada. But the fallout is the same. Dehydration is a real risk for mastitis AT ANY STAGE of lactation. And mastitis is serious. It can land a mother in hospital needing IV fluids, but even if it is not severe enough to require hospitalization, it can make her pretty sick and incapacitate her. 

Then we have the situation where I say my part and the mother takes it to the Rabbi and he gives her a Heter (permission) to drink and eat, yet she still decides to fast, out of what, guilt? Piety? Ladies, this is not Halacha. This is AGAINST Halacha.

Another recent case I was involved in was that of an older gentleman who had multiple health issues including diabetes, who was on antibiotics recovering from a chest infection and dehydration and actually argued with me when I forbade him from fasting (and this was for 17 Tammuz). I thought that was pretty extreme and certainly there is no question that he had a Heter to drink and eat freely. And yet he argued. I can only hope that he actually listened to me. Ignoring doctors' orders is not Halacha! 

So on YK if you have a Heter to not fast, then you don't fast, and you REST and you STAY HOME. You do NOT go to Shul. Always remember that, in active childrearing, pregnancy and breastfeeding, that you are doing Hashem's work and that is the greatest mitzvah of all. It is not a mitzvah to be sick and incapacitated and unable to care for yourself or your children. 

I'll say something else here: I recently saw a FB post where a mother was praising her 8 year old daughter who fasted on 9av and also looked after her because she was unwell due to the fast. 

Now I am sure that this child is a wonderful person and a credit to her parents and Klal Yisrael, but she is too young to fast. There is no Halacha that demands this of such a young child. I also hear of this thing of doing the last 3 fasts before turning Bar/bas mitzvah and I would like someone to enlighten me as to where this is written. So if any Rabbis out there could discuss this with me, please do. 

Oh, it's about chinuch (Jewish education), is it? I'm not saying that the kid should do nothing at all; they can 'fast till breakfast', or not eat treats. Older kids can fast till noon if they want to; some kids really get a feeling of achievement. But a young child should be actively discouraged from trying to do a full fast, especially where these days fall in the summer where the day is hot and long. Kids are vulnerable to dehydration and it's just not necessary. 

And, final word, watch out for the little perfect pious girl who just loves to fast, because it can be a mask for an eating disorder, just as excessive religiosity can mask OCD and other psychological issues. Just saying. 

Religious fasts have their importance, but please, approach with common sense in these cases. 

PS

I've had a fair bit of interest in this post now that Yom Kippur is imminent So I'm adding this comment:

My opinion and expertise relates largely to breastfeeding women, and my problem with these women fasting is the real risk of dehydration triggering mastitis. It can also trigger duct blockage which is less serious but mastitis can land you in hospital and even if it's not bad enough to cause hospitalization, it still can incapacitate. I think it's not good enough to say 'fast until you feel sick and then you can break your fast'. That's not the point. The point is to avoid falling sick; mastitis can strike the next day even if you didn't 'feel sick' with fasting. You need about 2 litres of fluids a day when breastfeeding; you can have 39mls (a 'cheekful' of fluid) every 9 minutes, so that would mean doing this for 7 hours or so to get enough fluid to stay out of trouble. This is referred to as 'shiurim' and is not considered to be breaking the fast. Water is probably good enough but those with a poor track record of fasting might have electrolytes. But I am not a Rav so please discuss with a sympathetic Rav. 
Re pregnancy of course it is NOT a good thing to go without water and fasting can bring on premature labour. But more than that I can't advise, speak to a Rav.