Spontaneous abortion rates, gravidity and neural tube defects.
Kline and her co-workers [20, 21] suggest that spontaneous abortions show no overall gravidity effect. However, spontaneous abortions seem to show a negative gravidity effect in some sibships (those containing an infant affected by anencephaly or spina bifida) [22]. It is inferred that there is a heterogeneity among spontaneous abortion sibships, and that there are other sibships in which spontaneous abortions show a positive gravidity effect (perhaps as a result of e.g. iso-immunization).
D000022:Abortion, Spontaneous / Q000150:complications*; D000757:Anencephaly / Q000209:etiology*; D001722:Birth Order; D005260:Female; D006801:Humans; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011379:Prognosis; D016136:Spina Bifida Occulta / Q000209:etiology*