Rebound Pregnancy

One of the things that we have observed over the years - something that has been noted by all Reproductive Endocrinologists - is the fact that some women will go through extensive infertility diagnosis and treatment programs without conceiving, stop the treatment, and within a few months conceive on their own. No one has put a specific name on such an occurrence. We prefer to call it a “rebound pregnancy”.

The reasons for this can probably never be proven but we think the following offers as good an explanation as any.

Almost all of the women who do conceive under these circumstances have been on an ovulation induction or augmentation program using either Clomiphene or gonadotropin therapy.

We have known for many years that the egg that is ultimately going to ovulate in any one given menstrual cycle actually begins to develop four to five months prior to the menstrual cycle in which it eventually goes onto to full maturity and ovulation. Turning this fact around and putting it another way, what happens in any one given menstrual cycle influences the next 4 to 5 menstrual cycles.

It is, therefore, reasonable to conclude that even though a pregnancy did not occur in one of the treatment cycles, the hormonal changes initiated by the therapy set in motion a sequence of events which allowed more normal ovulation to occur for the first few months following the cessation of medication. It is, therefore, reasonable to conclude that a pregnancy which occurs within the first 3 to 4 cycles after the cessation of active therapy is really part of the treatment and is a carry over for the reasons just mentioned.

For those couples going through a treatment program using either Clomiphene or gonadotropin therapy, particularly for those couples with “unexplained infertility” or with “minimal abnormality infertility” it may be reasonable to interrupt therapy for a month a two every six months or so to see whether a rebound pregnancy might occur. We recognize that infertile couples sometimes become quite anxious if they are not actively doing something to achieve a pregnancy. You would still be monitored during those cycles to make sure that everything was proceeding normally and to make sure that there is not a valid reason to maintain a more active approach. Nonetheless, it is something to consider when nothing else seems to be working.

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