The decision to tell or not to tell your work environment that you are undergoing assisted reproduction treatment depends, to a great extent, on the relationship you have with your coworkers.
Undoubtedly, it can be a subject that may raise uncomfortable questions that the person is not willing to answer because they are too private or, simply, because they come from people with whom he/she does not have the required confidence. Therefore, if you decide to talk about it at work, you must be very clear about how far you are going to tell, set limits and have prepared a series of assertive responses that cut off the intrusions.
On the other hand, talking to the person in charge so that he/she understands the situation can be beneficial and help to reduce the possible stress generated by frequent absences, but it will be, again, a very personal decision.