2nd time senna is def contraindicated with pregnancy, it causes contractions in order to push the contents of your colon out. Phsilliym caps are a stool softener a that don't cause strong contractions, and really help with constipation.
Also if you're constipated look at the iron in your prenatal. They often put really difficult to digest iron in prenatals. I take one without iron and take an iron supplement separately. 75% of constipation during pregnancy is thanks to prenatal iron tabs. The good stuff iron that prevents ADD, ADHD, and learning disabilities is Floridix, Spatone, and Proferrin. Add to orange juice and bam, no constipation but your blood will carry that much needed oxygen to baby. Anemia in third tri thanks to crappy iron supplements is the no. 1 cause of ADD, ADHD and cognitive disabilities. And how many kids have you heard of these days diagnosed with ADD & stuff like that. It seems like every other kid on the block...thanks to something totally preventable.
Those "stuff" you talk about are genetic! My son has asd and I often get people try to tell me what does and doesn't cause it, and I'm sorry people looking from the outside in haven't a clue, I've people try make me feel bad say its diet what ever you wanna blame it on. End of the day I live with it I breath it. My son got it through our bloods, my dad undiagnosed has asd, I am sure I am on the spectrum too. No amount of meds will prevent those things.
I don't mean to sound bitchy or hormonal but it is a subject that really irks me because people on the outside don't know what it's like having the whole world look in and start the blame game! And I realise you didn't say asd but adhd and add belong to the same branch.
you can also do damage by taking too much iron! So basically damned if you do or dont, but i know the reality verse what you read online and i can tell you every parent with a child like mine would agree, you can do all the research you want end of the day i live it! Never was anemic, only issue i had was high blood pressure due a none pregnancy issue. My son was always gonna be autistic, no amount of diet change would of changed that outcome, i think his birth excelled the severity of his asd. But to be honestits just scare mongering and makes parents like us feel like crap. We carry enough guilt its taken me years to forgive myself and believe i did nothing wrong. I ate healthy, walked regularly, took my pre natals, no iron issues. Not really wanting to debate with you but its a bigger world than just some numbers and possibilities on some page im not having a go, just sticming up for myself and other parents like me 
and setting the real information right for those that might be reading
today 
