The difficulty is that as a term of your student visa you would have had to advice the UKBA of any changed in your circumstances. This means that you should have told them once you ceased to be a student and are in breach of your student visa.
You are going to have to argue that your pregnancy was the reason for having to cease your studies. If you wrote or confirmed to your college that you wished to defer your studies then this will help.
You've got to write back to them and explain your position whilst at the same time backing this up with documentary evidence that corroborates what you are stating to them. Get a letter from your doctor confirming the dates of your pregnancy, get your maternity certificate. If you wrote to your college confirming that you wished to defer your studies until after your pregnancy then include this as well, if you did not and instead informed the college verbally then ask them to provide a letter stating that you did this.
If you husband is also the father of your child then you have a reasonable case to argue your Article 8 Right to a family life under Human Rights Act. They may refuse the application initially, if they do and grant you a right to appeal then you should take it to a local immigration solicitor immediately and ask for specific advice on the documentary evidence you have on the merits of your claim. It would be best to instruct the solicitor to act on your behalf in your appeal.
Your husband should eb able to provide his bank statements and payslips, he should formally request these from his bank and employer - they will have these available and there can be no excuse for not providing them.
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Edited by T_Graham12 on 10/20/2010 at 5:05 PM EST