I have written this letter to you because I think other people are too nice and concerned about hurting your feelings to give you critical feedback on the thought process basing your decisions, and because I think that examining your choices within the framework of your purported beliefs and aspirations will allow you to parse out a way forward that is not in conflict with those beliefs and aspirations. Also, acting in ways that are consistent with your ethics (your ethics as you have expressed them in your blog) may relieve the angst and desperation you have reported and will better serve the purpose of your blog, which is to inform others in your situation. Generally, I do not offer my opinion of people’s choices because I do not entertain their opinions of mine, but whereas you have actively solicited feedback by making you choices public I feel compelled to write the following.
I submit to you some things to consider:
You say that you are a vegan in pursuit of a more natural way of living. Veganism has underpinnings in social consciousness and the idea that we, humans, should pursue life in a way that is socially responsible. Given this nod toward supporting the greater good, would it not be socially responsible of you to invest resources (time, energy, money, emotion) into an existing child via adoption rather than sinking resources into the forced creation of a biological child?
You talk of a deep need to be a mother, so wouldn’t you be inclined to parent any child in need of a family? The act of mothering is a selfless devotion to the care and betterment of another person, no matter their age or origin. Your decision to use IVF implies that you are pursuing pregnancy for yourself first and foremost. This pursuit is contradictory to being a mother when opportunities to nurture existing persons abound.
Perhaps you should not feel so bad about the miscarriage. Your decision to pursue IVF implies that you have a scientific attitude toward the creation of life. That you would intervene to mechanically create an embryo outside of the womb and suspend the development of that embryo (via freezing) suggests that you see the embryo as a means to an end and not a life in and of itself. Thus, you lost the precursor to a life, a collection of divided cells, but not a baby, not even a fetus. Maybe you felt disappointment that you could not sustain the pregnancy, but you do not mourn the loss of a life.
Regarding the transfer of more than 1 embryo, consider that there are increased risks to mother and babies when pregnant with multiples. You have a responsibility to your potential child to not knowingly increase those risks by becoming pregnant with more than one child. You may want to implant the second embryo as an assurance that at least one will survive, but a mother would be less self-serving and choose to implant only one, if use IVF all.