Biomaterial Database

Male excess among anatomically normal fetuses in spontaneous abortions. 1987

J Byrne, and D Warburton

Estimates of the sex ratio in miscarriages, obtained mainly by cytogenetic or nuclear sexing methods, have yielded conflicting results. We report the results of a study of the anatomic sex ratio among embryos and fetuses derived from a consecutive series of 3,469 miscarriages. The overall sex ratio (M:F) was 1.25. The male excess was confined to normally formed specimens (1.30) and was present at all gestational ages up to 23 weeks and all sizes over 5 cm. Among malformed specimens the sex ratio was close to unity (0.92). Agreement between chromosomal and anatomic sexing was excellent, and the cytogenetic sex ratio among anatomically normal abortuses showed a similar excess of males. We hypothesize that an excess of anatomic males among fetal deaths suggests the presence of a discrete cause or causes that operate on normally formed embryos and fetuses, whereas loss of malformed embryos and fetuses may be due to other mechanisms that affect females as often as males.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D005260	Female		Females
D005865	Gestational Age	The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated from the onset of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization. It is also estimated to begin from fertilization, estrus, coitus, or artificial insemination.	Embryologic Age,Fetal Maturity, Chronologic,Chronologic Fetal Maturity,Fetal Age,Maturity, Chronologic Fetal,Age, Embryologic,Age, Fetal,Age, Gestational,Ages, Embryologic,Ages, Fetal,Ages, Gestational,Embryologic Ages,Fetal Ages,Gestational Ages
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000013	Congenital Abnormalities	Malformations of organs or body parts during development in utero.	Birth Defects,Congenital Defects,Deformities,Fetal Anomalies,Fetal Malformations,Abnormalities, Congenital,Defects, Congenital,Abnormality, Congenital,Anomaly, Fetal,Birth Defect,Congenital Abnormality,Congenital Defect,Defect, Birth,Defect, Congenital,Deformity,Fetal Anomaly,Fetal Malformation,Malformation, Fetal
D000022	Abortion, Spontaneous	Expulsion of the product of FERTILIZATION before completing the term of GESTATION and without deliberate interference.	Abortion, Tubal,Early Pregnancy Loss,Miscarriage,Spontaneous Abortion,Abortions, Spontaneous,Abortions, Tubal,Early Pregnancy Losses,Loss, Early Pregnancy,Losses, Early Pregnancy,Miscarriages,Pregnancy Loss, Early,Pregnancy Losses, Early,Spontaneous Abortions,Tubal Abortion,Tubal Abortions
D012744	Sex Ratio	The number of males per 100 females.	Ratio, Sex,Ratios, Sex,Sex Ratios