If a multiple pregnancy occurred spontaneously, the obstetrician would suspect a problem with the dates because the uterus would grow faster than usual. The gestational age of a pregnancy is determined from the first day of the last menstrual period (LMP).
In a multiple gestation, the uterine measurements would be larger than dates, which normally correspond. If multiple gestation is suspected, an ultrasound may be performed to determine the gestational age of the fetus or to check for more than one fetus. With the use of assisted reproductive technology, an ultrasound is usually performed with ten days to see if any of the embryos were successful with implantation, and a multiple gestation would be revealed at that time.
Following the birth of multiples, the placenta is carefully examined to determine if they are fraternal or identical. One placenta indicates identical twins.
A multiple pregnancy almost always means increased monitoring and surveillance for complications. This often means more frequent visits to the healthcare provider, serial ultrasounds to make sure that the babies are growing satisfactorily, amniocentesis to check for lung development, and close monitoring for preterm labor.