And in case she is pregnant the obligatory precaution is...

And in case she is pregnant the obligatory precaution is that she should observe iddah till the birth of the child or for forty-five days, whichever period is longer. 2525. The time of the iddah of divorce commences when the pronouncing of the formula of divorce completes, whether the woman knows it or not that she has been divorced. Hence, if she comes to know after the end of the iddah that she has been divorced, it is not necessary for her to observe iddah again.