Spina bifida and anencephaly in Scotland.

Data obtained from routine sources showed that from 1971 to 1982 the birth prevalences of spina bifida and anencephaly in Scotland fell. When known terminations after routine alpha fetoprotein screening were added to total births the adjusted birth prevalence could be calculated. In 1974-82 this fell by 40% for spina bifida (3 X 0-1 X 8) and 36% for anencephaly (2 X 2-1 X 4). These findings were compared with data on birth prevalences in England and Wales, Northern Ireland, and Glasgow. The fall in birth prevalences of spina bifida and anencephaly over the past decade appears to have been due both to a true fall in incidence as well as to increased screening and termination for these conditions.     

Spina bifida cystica and severe congenital bilateral talipes equinovarus in one twin of a monoamniotic pair: a case report

Background

Spina bifida and congenital talipes equinovarus (CTEV) are common congenital malformations which may occur together and increase morbidity. Monozygous twins are particularly at risk of these malformations and discordance in one type of malformation is typical. The occurrence of both spina bifida and CTEV in one twin of a monozygotic pair is rare.

Case presentation

A 22 year-old Cameroonian primigravida at 36 weeks of a twin gestation was received in our district hospital at the expulsive phase of labour on a background of sub-optimal antenatal care. A caesarean section indicated for cephalo-pelvic disproportion was performed and life monoamniotic male twins were extracted. The first twin was normal. The second twin had spina bifida cystica and severe bilateral CTEV. Routine postnatal care was ensured and at day 2 of life, the affected twin was evacuated to a tertiary hospital for proper management. He was later on reported dead from complications of hydrocephalus.

Conclusions

Spina bifida cystica with severe bilateral CTEV in one twin of a monoamniotic pair illustrates the complexity in the interplay of causal factors of these malformations even among monozygotic twins who are assumed to share similar genetic and environmental features. The occurrence and poor outcome of the malformations was probably potentiated by poor antenatal care. With postnatal diagnoses, a better outcome was difficult to secure even with prompt referral. Early prenatal diagnoses and appropriate counseling of parents are cardinal.

     

Spina bifida and anencephaly: miscarriage as possible cause.

In two retrospective Liverpool surveys the domestic, family, dietary, and medical environments of the mothers of children affected by anencephaly or spina bifida, or both (ASB) were examined. None seemed to be of more than minor importance and the findings of others were therefore examined to see if they suggested a major factor. The most promising lead came from the hypothesis that ASB is usually due to an interaction between twin fetuses or between a fetus and residual trophoblastic material from the previous normal pregnancy, particularly when this is of the opposite sex to the propositus. The sex finding was not confirmed. It was noted that hydatidiform moles, like children with ASB, were usually female and that moles and choriocarcinomas on the one hand and children with ASB on the other occurred in mothers of similar ages, but were to some extent reciprocal in geographical incidence. This suggested that trophoblastic disease might be a factor common to all three and if so then one would expect the frequency of miscarriages to be higher immediately before than immediately after the birth of an ASB child, since mole and choriocarcinoma seldom follow a normal pregnancy. An analysis of published data confirmed that this was almost certainly so. Hence residual pathological trophoblastic material from either a previous miscarriage or a co-twin may interact unfavourably with another fetus to produce ASB and this may be the primary cause of the condition. The hypothesis is consistent with the observed lack of concordance in twins, the high incidence in females, the maternal age effect, and the greater prevalence in social classes IV and V.     

Spina bifida and so-called asplenia syndrome occurring separately in sibs.

Attention is drawn to the possibility that neural-tube defects may sometimes be associted with the so-called asplenia syndrome (Ivemark syndrome). This hypothesis is based upon a family in which one child had spina bifida and hydrocephaly and another had cardiovascular and other fissural anomalies, similar to Ivemark syndrome. The family history, moreover, revealed several cases of anencephaly and/or spina bifida, both on the paternal and maternal sides.