How can that be controlled?
You go to the ob/gyn saying, we’ve been trying but nothing’s happening. You are prescribe some clomid tablets and told to go home and ‘bo-di-oh-do’ at the right time...unfortunately at this early stage there is either very little or no monitoring—when you advance to later stages (intrauterine inseminations, in vitro attempts), the reproductive endocrinologist (a specialist in fertility, unlike ob/gyns) will monitor the patient with daily ultrasounds and blood work measuring certain reproductive hormones. The best doctors will cancel the cycle if there are too many eggs being produced for an IUI (artificial insemination).
It's simple, but expensive. The doctors monitor the woman's follicle counts through ultrasound. Or, the doctors prevent the woman from ovulating, then harvest the eggs at the appropriate time. Then they only fertilize a set number of eggs.