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The placenta in multiple pregnancy: outstanding issues.

K Benirschke·E Masliah
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Abstract

The present paper reviews the placental development in multiple gestations and highlights the twin-to-twin transfusion syndrome, its recognition and possible therapy, and some of the consequences of fetal death of one twin. It presents data on discordance for structural anomalies in monozygotic twins. These aspects are discussed with respect to their possible pathogenetic origins.

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AnencephalyCongenital AbnormalitiesEncephaloceleFemaleFetal DeathFetofetal TransfusionGestational AgeHumansMouth AbnormalitiesPlacentaPregnancyPregnancy, MultipleTwins, MonozygoticJournal ArticleReview

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K Benirschke, E Masliah. 2001. The placenta in multiple pregnancy: outstanding issues.. https://doi.org/10.1071/rd01037

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Extraocular eye muscles in human fetuses with craniofacial malformations: anatomical findings and clinical relevance.

Anomalies of the extraocular muscles have been suspected to be present frequently in patients with craniofacial malformations. We studied the extraocular musculature in the orbits of 15 anencephalic human fetuses between the 5th and 10th months after gestation, and in one fetus with an occipital meningocele and a large defect of the left cranial base. The findings were compared to those in nine normal age-matched fetuses. All malformed fetuses exhibited special features of the levator palpebrae superioris muscle, either its absence, an anomaly of the muscle belly, or an anomalous insertion. In addition, deficient or aberrant muscle bellies of the oblique and rectus muscles were found. In anencephaly, the frontal bone is condensed, forming narrowed orbital cavities with hypotelorism. Frequent disturbance of extraocular muscle development in fetuses with craniofacial malformations is implicated. The presented specimens are examples of extreme variants of cranial and craniofacial malformation syndromes. Thus, similar findings of extraocular muscles might also be regularly found in clinically relevant craniofacial malformations. This would force new considerations about diagnostic and therapeutic approaches to patients with craniofacial malformations.

Anencephaly↗
PubMed2006

[Effect of flour folic acid fortification on the incidence of cranio encephalic congenital defects].

BACKGROUND: In Chile, flour is fortified with folic acid since 2000, and the incidence of neural tube defects has decreased. Cranio-encephalic congenital defects (CECD) have a wider clinical scope, includind classical neural tube defects (NTD) such as anencephalia and acrania, but also incorporating other defects. Therefore, the effects of folic acid fortification on the incidence of CECD could be different. AIM: To study the effect of folic acid fortification on the incidence of CECD. MATERIAL AND METHODS: All prenatal diagnoses of CECD and cases registered locally in the Latin American Collaborative Study of Congenital Malformations (ECLAMC) were reviewed. The obtained data were crossed with all death certificates of newborns or stillborns of more than 500 g in the Sixth Region, in Central Chile. All cases were classified again in four subtypes, according to their phenotype. The incidences of all subtypes prior (1996-2000) and after folic acid supplementation (2001-2004), were compared. RESULTS: Between 1996 and 2004, there were 64 cases of CEDC among 109,176 infants born alive. The global rate was 8.86 per 10,000 born alive in the period prior to fortification and 3.03 per 10,000 born alive after fortification. Comparing both periods, there was a 66% reduction in all CECD and a 77 and 100% reduction in subtypes A and B of CECD, respectively (p <0.05). No significant reductions in type C and D CECD, were observed. CONCLUSIONS: After the start of flour folic acid fortification, there was a global reduction in the incidence of CECD. However, only types A and B CECD, supposedly more responsive to folic acid, were reduced.

Anencephaly↗
PubMed2006

Weekly administration of folic acid and epidemiology of neural tube defects.

OBJECTIVE: In 1999, a folic acid campaign for prevention of neural tube defects was started in Nuevo León, México, with the recommendation of taking a 5000 -mcg tablet of folic acid per week. The purpose of this study was to compare the epidemiology of neural tube defects after four years of the campaign. METHODS: Cases of anencephaly, spina bifida, and encephalocele (ICD Q00, Q01, Q05, 10th Ed.) from public and private hospitals were registered by immediate notification, death certificates, and fetal death registries. Comparisons of neural tube defects rates, phenotype distribution of cases, and sex ratios, registered before and after the folic acid campaign, were done using the Student's t Test and Chi square test. RESULTS: There was a 50% reduction in the incidence of anencephaly and spina bifida cases from 93 in 1999 (1.04x1000) to 46 in the year 2003 (0.56x1000) (p<0.001). Spina bifida cases declined up to 70% in 2002 and anencephaly cases up to 50% in 2003. In 1999, overall, the ratio (females: males) was 0.66 with female excess; the sex ratio was similar for anencephaly and spina bifida cases. In the year 2000, female cases showed a significant reduction for both spina bifida and anencephaly (75% and 56% respectively); the sex ratio was 0.57 with a greater male excess for both phenotypes. CONCLUSIONS: Weekly administration of 5000 mcg of folic acid reduces the incidence of neural tube defects 50%, primarily spina bifida, with a higher reduction of female cases.

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