No. Exercise has NOT been shown to cause miscarriage. It is actually better to exercise during #pregnancy if pregnancy is uncomplicated.
Ahhh it is very easy to blame ourselves- However, I need to reassure you that there is no evidence to suggest that exercise causes #miscarriage, Please believe that 🙏
Just before my second son, I had a miscarriage and straight away I thought it was my training- I researched and searched- I guess I just wanted an answer- whyyyyy.... but there is just little to no evidence that links exercise to cause miscarriage.
In 2019 a study analyzing 23 miscarriages noted that "prenatal exercise is not associated with increased odds of miscarriage." 
Prior to this - A study reviewed 100 women in 2017 concluded that even vigorous activity could not be tied to miscarriage risk. 
In fact, there is an incredible amount of evidence that strongly supports us, women, to exercise during pregnancy.
I absolutely support this and I have/am training with many women who have had successful pregnancies/IVF. Online mostly and in-person for over 7 years.
If you have just had a miscarriage please please sit within and allow yourself to really know - you did not have anything to do with your miscarriage. Whether you changed your routine or kept to your norm unfortunately your miscarriage would have still taken place.
Please reach out to Tommys' foundation for support- they are professional and are there to help us. https://www.tommys.org/baby-loss-support
If you are worried about training during your pregnancy I would advise that you take your first-trimester slower and opt for low-impact training.
Opt for the modifications for example inclining your exercises using a step or the wall. Lift to toes rather than jump and forget ab crunches
Work with lighter weights
Always leave your workout feeling like you could have done another 10 more minutes
I would also recommend adapting the above into your training during your #IVF treatment.
Allow yourself to heal and this means inside as well- please reach out to me as I am specialised in #preandpostnatalexercise .
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Davenport MH, Kathol AJ, Mottola MF, et al. Prenatal exercise is not associated with fetal mortality: A systematic review and meta-analysis. Br J Sports Med. 2019;53(2):108-115. doi:10.1136/bjsports-2018-099773
Verdière S, Guinhouya BC, Salerno D, Deruelle P. Should physical activity be contraindicated during pregnancy in relation to its potentially related risks?. Gynecol Obstet Fertil Senol. 2017;45(2):104-111. doi:10.1016/j.gofs.2016.12.019
Physical Activity and Exercise During Pregnancy and the Postpartum Period: ACOG Committee Opinion Summary, Number 804. Obstet Gynecol. 2020;135(4):991-993. doi:10.1097/AOG.0000000000003773