الجواب وبالله التوفيق

As long as the divorce is issued with absolute words, pregnancy or non-pregnancy, the state of cleanliness or menstruation and presence or absence of witnesses does not have any effect on its validity, it takes effect in all conditions. Therefore as per the situation described in your question 3 divorces have taken effect and your wife has become haram(impermissible) upon you through talaq-e-mughallidha(irrevocable divorce). It is haram to live together without performing Shar‘ai Halalah.

Since the wife is pregnant the period of ‘iddah will complete with the end of the pregnancy and there is no possibility of reconciliation without performing Shar‘ai Halalah. If the woman after the completion of her pregnancy marries another man, her marriage gets consummated, and then this new marriage ends through divorce or the death of the new husband, then she can marry her pervious husband. This is the only method for reconciliation.

Since you had issued three divorces in the first incident, the woman became released from your Nikah immediately as a result of that and the other two incidents have no effect on the already finalized divorce and the divorces issued later are useless and inconsequential.

وَاُولَاتُ الۡاَحۡمَالِ اَجَلُهُنَّ اَنۡ يَّضَعۡنَ حَمۡلَهُنَّ    (الطلاق،4 

وطلاق الحامل یجوز عقیب الجماع   (الھدایہ کتاب  الطلاق ، ص 375، ج2

وان کان الطلاق ثلاثا فی الحرۃ۔۔۔۔لم تحل لہ حتی تنکح زوجا غیرہ۔ نکاحا صحیحا ویدخل بھا ثم یطلقھا او یموت عنھا، والاصل فیہ قولہ تعالٰی فان طلقھا فلا تحل لہ  من بعد حتی تنکح زوجا غیرہ والمراد۔۔۔الطلقۃ الثلاثہ 

 (کتاب النوازل، ص 197، ج9، بحوالہ ھدایہ، فتاویٰ ھندیہ وغیرہ)

واللہ اعلم  بالصواب