This is the first part of a scheduled two-part study on the human sex ratio. The objectives of the study are "first to summarize much that is known about the variation of the human sex ratio at birth; second to relate these findings to a hypothesis designed to explain them; and third to outline some of the research needed to test the hypothesis. In the present paper the literature will be reviewed: in the second paper the adequacy of the hypothesis to accommodate the data will be discussed and a research program will be outlined." Factors associated with variations in the sex ratio include race season war legitimacy birth order and paternal age. Consideration is also given to other factors that may affect the sex ratio including psychological factors smoking handedness of parents the location of an anomalously implanted pregnancy occupation and maternal age. (EXCERPT)

The human sex ratio. Part 1: A review of the literature.

Abdominal gestation is a relatively uncommon complication of pregnancy. Previous reports describe a high incidence of fetal deformations and mortality as well as maternal mortality. A case of twin abdominal gestation is presented and the literature concerning abdominal pregnancy since 1809 is reviewed. The survival rate of liveborn infants of 30 or more weeks gestation was 63%. The maternal mortality rate since 1809 was 18.2%, but this has decreased to 4.5% during the last 20 years. The combined rate of malformations and deformations in the infants was 21.4%. The most common deformations observed were facial and/or cranial asymmetry and various joint abnormalities. Among the most common malformations were limb deficiency and central nervous system malformations. Proposed mechanisms of compression and vascular disruption are discussed. © 1993 Wiley-Liss, Inc.

Malformations and deformations in abdominal pregnancy.

This analysis attempts to highlight the varied presentations, diagnostic difficulties, management and subsequent obstetric performances of women managed for advanced abdominal pregnancy. A retrospective analysis of all 20 cases of abdominal pregnancies between 1976 and 2006, at the Mater Misericordiae Hospital, Afikpo, southeastern Nigeria was performed. There were 20 cases of abdominal pregnancy out of 58,000 deliveries, giving an incidence of 0.34 per 1,000 deliveries. The diagnoses were missed in 10 cases and there was one maternal death. There were four live births, two early neonatal deaths and four cases of lithopedion. The placenta was removed in 11 cases. Though the duration of hospital stay was longer in women in whom the placenta was left in situ compared to those in whom the placenta was removed, the observed difference was, however, not statistically significant (p value, 0.538). The majority of the women were lost to follow-up over the years; however, of the five women successfully followed up, only two (40%) had subsequent childbirth. The rate of 50% missed diagnosis in this study highlights the need for a high index of suspicion in the diagnosis of abdominal pregnancies as the clinical features are varied. It calls for vigilance on the part of the obstetrician. The maternal and fetal outcomes relate to early diagnosis and skilled management.

A 30-year review of advanced abdominal pregnancy at the Mater Misericordiae Hospital, Afikpo, southeastern Nigeria (1976-2006).

We report on an abdominal pregnancy that presented as a missed abortion at 16 weeks' gestation and review the literature on the management of abdominal pregnancy. The clinical presentation of abdominal pregnancy varies, and the diagnosis depends on a high index of suspicion. Ultrasonography is useful for early diagnosis of the condition. The management depends on the gestation at presentation; for advanced abdominal pregnancy, surgical intervention is recommended. The treatment of the placenta is a matter of controversy. In general, expectant management is suggested. When the placenta is left behind, the use of prophylactic methrotrexate is not advocated. An awareness of abdominal pregnancy is very important for reducing associated morbidity and mortality.

Abdominal pregnancy presenting as a missed abortion at 16 weeks' gestation.

A full-term abdominal pregnancy culminating in the birth of a live healthy baby by laparotomy is described.

S. M. Goon

Papers

The paediatric aspects of advanced abdominal pregnancy