PIP: This article reviews the cumulative data on multiple pregnancies which are the result of ovulation induction. Generally, those patients who require ovulation induction fall into 2 groups--those with primary or secondary amenorrhea, low levels of endogenous gonadotropins, and lack of endogenous estrogen activity, and those with anovulation due to menstrual disorders who have evidence of endogenous estrogen activity. The various ovulation-inducing preparations are discussed and they include gonadotropins ([hPG] human pituitary gonadotropin and [hMG] human menopausal gonadotropin), clomiphene, and agents which inhibit prolactin secretion. A variety of treatment schedules for gonadotropin administration have been advised and nearly all are based on the fact that hPG and hMG result in follicular growth and maturation and that ovulation can be induced by a triggering dose of hCG. A nonoverlapping regimen results in a significantly lower incidence of multiple pregnancies. Clomiphene administration must be varied according to the individual patient. Various combination therapies exist such as clomiphene and hMG or hPG or Parlodel and clomiphene or Parlodel and pergonal or LH-RH. Early diagnosis of multiple pregnancies is important since it enables the early institution of therapeutic measures which are likely to prevent maternal complications. Among the diagnostic methods are clinical examination, ultrasonography, radiography, and determinations of biochemical parameters. These multiple pregnancies can result in maternal complications and its effects on the fetus can be serious as well. Spontaneous abortion, premature delivery, perinatal mortality, and congenital malformations are some of the complications which can occur. There are attempts being made to reduce the incidence of multiple births by monitoring estrogens, monitoring follicular diameter measurements, selecting appropriate patients for therapy, and choosing a suitable regimen of treatment. Common measures taken in the management of multiple pregnancy include bed rest, myometrial relaxants, and suturing of the cervix.