Taking The Birth Control Pill Prior to IVF: Does It Compromise Outcome?
It is often stated that it is not a good idea to take birth control pills (BCP) before starting controlled ovarian hyperstimulation (COH) for IVF, the reason being that it will suppress follicle development, prolong the cycle of stimulation and compromise egg/embryo quality. This is not accurate because it is only half of the story.
It is a fact that if a woman goes directly from a BCP to COH, without overlapping the last few days on the pill with a GnRH agonist (GnRHa) such as Lupron, Nafarelin, or Buserelin, the stimulation will very often be compromised. However, this is NOT the case if GnRHa is given for the last 4-6 days on the BCP prior to commencing ovarian stimulation with gonadotropins….and here is why:
Towards the end of a natural ovulatory cycle, starting a few days prior to menstruation, the corpus luteum (the structure that produces estrogen and progesterone after ovulation) starts to fail. This is associated with a rise in blood levels of follicle stimulating hormone (FSH) which in turn triggers the final process of egg recruitment and development of antral follicles, in preparation for use in the upcoming cycle. Without such FSH triggering, egg and follicle preparation is more likely to be compromised.
Administration of a birth control pill (BCP) suppresses FSH release by the pituitary gland, blocks ovulation and thus prevents formation of the corpus luteum. Accordingly, when a woman is on BCP and immediately begins COH with gonadotropins upon menstruation following discontinuation of the pill, she would be initiating ovarian stimulation without having completed egg recruitment and antral follicle development. As a result, follicular response to COH will usually be delayed and blunted. In the process, follicle and egg development is often compromised and the length of the ovarian stimulation cycle is prolonged significantly. Perhaps now it will be appreciated why starting ovarian stimulation coming directly off the BCP is less than ideal.
In my view, it is not only acceptable, but even ideal to take the BCP for at least one cycle prior to starting COH in preparation for IVF. Doing so allows one (without prejudice) to better plan and time cycles of IVF. Furthermore, since the BCP also suppressed LH, it is often especially advantageous in older women, in women with diminished ovarian reserve and in those with PCOS (in whom high LH levels can compromise egg/embryo quality). However, when women undergoing IVF launch their treatment cycles with a BCP, it is imperative to overlap the BCP with GnRHa for several days prior to menstruation and initiation of COH. The reason for this is that preceding GnRHa administration, the pituitary gland expunges FSH, which upon reaching the ovaries, serves to prepare eggs and antral follicles for the upcoming ovarian stimulation with gonadotropins. Simply stated, the combined use of BCP/GnRHa prepares the ovary for COH by supplanting the natural stimulus for FSH release that would otherwise occur with a failing corpus luteum.
The message is that the use of a BCP to set up a cycle of IVF should always include overlapping with a GnRHa for a few days before the stimulation begins. If this is done the BCP will NOT suppress or compromise response to COH.