Why such low chance of twins/higher order multiples on clomid, (clomiphene) when it is so common to produce more than one follicle? does hcg trigger up the odds?

Clomid (clomiphene): Clomid (clomiphene) patients do have a higher rate of twins than spontaneous pregnancy rates, but proper clomid (clomiphene) use usually leads to fewer appropriate size follicles than the injectible fertility meds. The advantage is less chance of ovarian hyperstimulation, which can lead to torsion and surgery/possible loss of the ovary. Hcg won't necessarily increase twin rates.