Term		Definition
Anembryonic pregnancy		Presence of a gestational sac larger than 18 mm without evidence of embryonic tissues (yolk sac or embryo); this term is preferable to the older and less accurate term “blighted ovum”
Ectopic pregnancy		Pregnancy outside the uterine cavity (most commonly in the fallopian tube) but may occur in the broad ligament, ovary, cervix, or elsewhere in the abdomen
Embryonic demise		An embryo larger than 5 mm without cardiac activity; this replaces the term “missed abortion”
Gestational trophoblastic disease or hydatidiform mole		Complete mole: placental proliferation in the absence of a fetus; most have a 46, XX chromosomal composition; all derived from paternal source
		Partial mole: molar placenta occurring with a fetus; most are genetically triploid (69, XXY)
Heterotopic pregnancy		Simultaneous intrauterine and ectopic pregnancy; risk factors include ovulation induction, in vitro fertilization, and gamete intrafallopian transfer
Recurrent pregnancy loss		More than two consecutive pregnancy losses; “habitual aborter” has also been used but is no longer appropriate
Spontaneous abortion		Spontaneous loss of a pregnancy before 20 weeks' gestation
	Complete abortion	Complete passage of all products of conception
	Incomplete abortion	Occurs when some, but not all, of the products of conception have passed
	Inevitable abortion	Bleeding in the presence of a dilated cervix; indicates that passage of the conceptus is unavoidable
	Septic abortion	Incomplete abortion associated with ascending infection of the endometrium, parametrium, adnexa, or peritoneum
Subchorionic hemorrhage		Sonographic finding of blood between the chorion and uterine wall, usually in the setting of vaginal bleeding
Threatened abortion		Bleeding before 20 weeks' gestation in the presence of an embryo with cardiac activity and closed cervix
Vanishing twin		A multifetal pregnancy is identified and one or more fetuses later disappear (occurs more often now that early ultrasonography is common); if early in pregnancy, the embryo is often reabsorbed; if later in pregnancy, it leads to a compressed or mummified fetus or amorphous material