Hello from JustAnswer.
Most women with an ovarian dermoid cyst of this size would not have problems with weight gain/inability to lose weight or infertility related to the cyst.An ovarian dermoid cyst of this size will usually not cause symptoms, and it is an accidental discovery when an imaging testis done for another reason. Consequently, most women with an ovarian dermoid cyst of this size do not need surgery, although the usual approach would be periodic monitoring.
It would typically require a larger ovarian dermoid cyst to interfere with ovarian function or to affect fertility. For any couple that has been trying to get pregnant for two years without success other than the one pregnancy that was lost, it is appropriate to undergo a thorough evaluation for conditions that can be affecting fertility, and if the women is also having difficulty with losing weight, a particular emphasis on an endocrine evaluation would be appropriate. If a thorough evaluation does not show any other condition that could be causing infertility or inability to lose weight, then it may be appropriate to re-visit the question of whether the ovarian dermoid cyst may be affecting ovarian function at a smaller size than would be expected. But the decision would usually be based on the lack of findings of a thorough evaluation, not just the inability to get pregnant or to lose weight.
If I can provide any additional information, please let me know.
Please let me know if I can provide any further assistance.