It is recommended to first watch this youtube video by Zakir Naik in which he explains what Islam advice for pregnant womens during Ramadan month regarding fasting and breast feeding.
The biological imbalance caused by fasting can make the course of the pregnancy difficult. It is desirable that the mother does not fast during the first quarter. This is an important period for embryogenesis this time requires a permanent state of biological balance. Also when a pregnant woman decides to fast, she must remain vigilant on its actual physical resistance to fasting.
In late pregnancy, the mother also needs a biological equilibrium guaranteeing sufficient strength necessary to face the ordeal of childbirth. Also, the last trimester of pregnancy is a time when fetal growth is paramount and fasting could adversely affect fetal development.
In case of complications during pregnancy, in addition to the pregnancy is further aggravated disease.
Overall, fasting during pregnancy is not recommended whatever the period.
We wish you a happy and healthy Ramadan Mubarak 2016