Yes my fasts were water only. The first fast was 28 days and resulted in hypokalemia( low potassium) and the second fast was 32 days. I found the second fast easier perhaps because I had completely changed my eating patterns. I also started juicing fresh fruits and vegetables more regularly. I was not prepared for the first fast as in I did not merge into it slowly or have a completely proper diet beforehand.
Just a thought. If you fast thirty days, you must refortify at least 30 days, however if you are planning on having a baby, from what I understand I would ideally fortify you body for at least two months post fast in preparation before conception ie 1:2 ratio. Preparing for conception and pregnancy is like having a good insurance policy on your health and the baby's future. Just my 2 cents.
Probably a fasting advisor might be really good to guide you and you can find them at fastingconnection .com or I think Dr. Bass does phone consults you can look up his website. Ask about fasting, discuss the length of you plan, how long adequate fortification of the tissues with take in preparation for a pregnancy and suitable diet postconception for the baby's health and to optimize yours.