SAM, I wonder a bit becasue your wife's condition is 100 % expected... it is normal for pregnant and breastfeeding ladies to be deficient on B6 (and significantly) due to efect of hormones and producing of milk, of course this needs supplementation to avoid numbness and tingling, but not necessarily costly one. As for thyroid issues, medical sciense knows already for a long time about condition called 'post-labour thyreoiditis', and also it is known to be a self-remedied in about 12 month, it is believed to be a reaction of immune system of rboth presence of a baby tissues and then for severing this link after labours.So I mean both issues are not unusual, are common, and normally do not need any specific investigation of reasons or costy treatment.Hope your family is well and happy. Time also works for you in this case.