The cramping during breastfeeding is normal and is not associated with miscarriage. Your best bet would be to take red raspberry leaf and vitamin C.
Honestly I don't know what would be worse weaning and then miscarrying and knowing what you took away from your daughter. Or continuing and miscarrying and blaming yourself even though it has nothing to do with breastfeeding.
Realistically the chances of miscarrying are the same either way.
There is no way to really wean abruptly with no trauma, and any gradual method is going to take you out of miscarriage range anyway. The only way to figure out what cup she will take is to try. However you are probably going to have to stop sleeping with her as well, I can't even imagine the stress of stopping both at once.
She has no need of either formula or cow's milk as long as her diet is sufficient.
The nature of breastfeeding contractions
http://kellymom.com/nursingtwo/excerpts/03bfcontractions.html
http://kellymom.com/nursingtwo/excerpts/02miscarriage.html
What are miscarriage and preterm labor experts saying?
Lesley Regan, PhD, MD, heads the Miscarriage Clinic at St. Mary’s Hospital in London, the largest referral unit in Europe, and is the author of Miscarriage: What every woman should know. She was surprised to hear that anyone considers issues related to miscarriage to be reasons for weaning. She added:
Once a pregnancy is clinically detectable, breastfeeding should pose no added risk of pregnancy loss. There isn’t any data suggesting a link between breastfeeding and miscarriage, and I see no plausible reason for there to be a link.
Obstetrician David Weismiller, MD, wrote a synthesis of research on preterm labor for the American Academy of Family Physicians; he is an assistant professor and director of women's health in the Department of Family Medicine at East Carolina University School of Medicine, Greenville, NC. He concurs that there is no evidence that implicates breastfeeding in increasing the risks of preterm labor in healthy pregnancies.
... from Chapter 12: Health Concerns
Read other excerpts from this book
"It has been a pleasure to have the opportunity to read this authoritative account on breastfeeding during pregnancy. I am delighted to have been asked to comment specifically on the risks of miscarriage for a breastfeeding woman. Hilary Flower has provided a detailed explanation that is easily accessible to the lay person, as to why the normal pregnant uterus only responds weakly to the action of oxytocin hormone until the very end of pregnancy. Undoubtedly, this is one of nature's own safety checks to prevent miscarriage and preterm labour in women continuing to breastfeed regularly during their next pregnancy. I feel sure that this book will provide women with confidence and reassurance to believe that 'breast is best' for their baby."
Lesley Regan, PhD, MD
Head of the Recurrent Miscarriage Clinic at St. Mary's Hospital in London, the largest miscarriage referral unit in Europe, and author of Miscarriage: What every woman should know
http://kellymom.com/nursingtwo/articles/bfpregnancy_safety.html#uterus
The well-protected uterus
The specter of breastfeeding-induced preterm labor appears to spring in large part from an incomplete understanding of the interactions between nipple stimulation, oxytocin, and pregnancy.
The first little-known fact is that during pregnancy less oxytocin is released in response to nipple stimulation than when a woman is not pregnant.5
But the key to understanding breastfeeding during pregnancy is the uterus itself. Contrary to popular belief, the uterus is not at the beck and call of oxytocin during the 38 weeks of the “preterm” period. Even a high dose of synthetic oxytocin (Pitocin) is unlikely to trigger labor until a woman is at term.6
Instead, the uterus must actively prepare in order for labor to commence. You could say that there are two separate states of being for the uterus: the quiescent baby-holder and the active baby-birther. These states make all the difference to how the uterus responds to oxytocin, and so, one can surmise, to breastfeeding. While the baby is growing, the uterus is geared to have a muffled response to oxytocin; at term, the body’s preparations for labor transform the uterus in ways that make it respond intensely to oxytocin.
Many discussions of breastfeeding during pregnancy mention “oxytocin receptor sites,” the uterine cells that detect the presence of oxytocin and cause a contraction. These cells are sparse up until 38 weeks, increasing gradually after that time, and increasing 300-fold after labor has begun.6,7 The relative scarcity of oxytocin receptor sites is one of the main lines of defense for keeping the uterus quiescent throughout the entire preterm period—but it is not the only one.
A closer look at the molecular biology of the pregnant uterus reveals yet more lines of defense. In order for oxytocin receptor sites to respond strongly to oxytocin they need the help of special agents called “gap junction proteins”. The absence of these proteins renders the uterus “down-regulated,” relatively insensitive to oxytocin even when the oxytocin receptor site density is high. And natural oxytocin-blockers, most notably progesterone, stand between oxytocin and its receptor site throughout pregnancy. 8,9,10
With the oxytocin receptor sites (1) sparse, (2) down-regulated, and (3) blocked by progesterone and other anti-oxytocin agents, oxytocin alone cannot trigger labor. The uterus is in baby-holding mode, well protected from untimely labor.4