Advances in Fetal Surgical Repair of Open Spina Bifida.

Spina bifida remains a common congenital anomaly of the central nervous system despite national fortification of foods with folic acid, with a prevalence of 2-4 per 10,000 live births. Prenatal screening for the early detection of this condition provides patients with the opportunity to consider various management options during pregnancy. Prenatal repair of open spina bifida, traditionally performed by the open maternal-fetal surgical approach through hysterotomy, has been shown to improve outcomes for the child, including decreased need for cerebrospinal fluid diversion surgery and improved lower neuromotor function. However, the open maternal-fetal surgical approach is associated with relatively increased risk for the patient and the overall pregnancy, as well as future pregnancies. Recent advances in minimally invasive prenatal repair of open spina bifida through fetoscopy have shown similar benefits for the child but relatively improved outcomes for the pregnant patient and future childbearing.

Potential association between infertility and spinal neural tube defects in offspring.

BACKGROUND: We examined the possible association between infertility and spinal neural tube defects (NTDs). METHODS: This is a nested case-control study within the Kaiser Permanente Medical Care Program (KPMCP) in Northern California. Among a birth cohort of 110,624 singleton infants > or = 36 weeks gestation, 1994-1997, we electronically identified cases of spinal NTDs and confirmed the diagnosis by chart review. Controls (n = 1,608) were randomly selected from the birth population. History of infertility was defined as: (1) physician diagnosis of infertility; (2) prescription for an infertility medication noted in the KPMCP pharmacy; and/or (3) evaluation at 1 of 15 infertility clinics in Northern California. RESULTS: Eighteen infants diagnosed with spinal NTDs (prevalence 1.6/10,000) included 13 with spina bifida cystica and 5 with spina bifida occulta. Case mothers were more likely to have a history of infertility (4/18 vs. 96/1,608, OR 4.3, 95% CI 1.01-14.0), and to have been prescribed clomiphene citrate within the window spanning 60 days before to 15 days after conception (3/18 vs. 32/1,608, OR 11.7, 95% CI 2.0-44.8). CONCLUSION: This exploratory study suggests that infertility may be associated with an increased risk of spinal NTDs among liveborn, term infants.

Paternal occupational exposure around conception and spina bifida in offspring.

A multi-center case-referent study was conducted on the relation between paternal occupational exposure and spina bifida in offspring. Cases were born between 1980 and 1992 in The Netherlands. Referents were recruited from hospitals and from the general population. Postal questionnaires were used to gather information on occupation and potential confounders. Through job-specific telephone interviews with 122 case fathers and 411 referent fathers, detailed exposure information was collected on specific tasks, the use of chemical or physical agents, frequency of exposure, and use of protective equipment. The study yielded statistically significant associations between spina bifida and low exposure to welding fumes (OR = 1.6, 95% CI: 1.0-2.6) and low exposure to UV radiation during welding (OR = 2.6, 95% CI: 1.2-5.6), and suggestive findings of an association between spina bifida and moderate or high exposure to cleaning agents, moderate or high pesticide exposure (OR = 1.7, 95% CI: 0.7-4.0), and stainless steel dust (OR = 2.0, 95% CI: 0.8-5.2). No associations were identified for other paternal occupational exposures, such as organic solvents.

Spina bifida and parental occupation.

To examine the association between parental occupation and spina bifida in offspring, we conducted a multicenter case-referent study in the Netherlands. Cases were children with spina bifida aperta from nine different hospitals throughout the country; the referent group comprised population-based referents who were randomly drawn from municipal birth registries. All children were born between 1980 and 1992. We collected data using postal questionnaires for both parents with questions about occupational title, industry, daily occupational activities, and a number of potential confounders. We were able to include 353 cases and 1,329 referents in the analyses. We found increased risks for maternal agricultural occupations [odds ratio (OR) = 5.6; 95% confidence interval (CI) = 1.8-17.8] and for cleaning women (OR = 1.9; 95% CI = 0.9-3.9). For the fathers, we saw increased odds ratios for welders (OR = 2.1; 95% CI = 0.6-7.0) and transport workers (OR = 1.4; 95% CI = 0.9-2.1).

Maternal occupational exposure during pregnancy and the risk of spina bifida.

OBJECTIVES: A case-control study was carried out to explore associations between spina bifida and occupational exposure of the mother. METHODS: The cases were children with spina bifida aperta born between 1980 and 1992 from nine hospitals in the Netherlands. The controls were children born healthy in the same period as the cases, from hospitals and from the general population. Data collection was carried out in two steps. Firstly, postal questionnaires were sent to all the parents of cases and controls to gather information on occupations and potential confounders. In the second phase of the study, information on specific exposures was collected by means of job and task specific personal interviews. Interviews were performed with 55 case mothers and 66 control mothers who had occupations with a potential for chemical or physical exposure. Those exposures were assumed to be negligible for--for example, teachers and secretaries, so personal interviews were not indicated for these women. Information was collected on specific tasks in the period just after conception, and on the associated use of chemical or physical agents, frequency of exposure, and use of protective equipment. RESULTS: The analyses of occupation showed an increased risk for women working in agricultural occupations (OR = 3.4, CI:1.3-9.0), and, although less distinct, for cleaning women (OR = 1.7, CI:0.9-3.4). Only a few women seemed to be occupationally exposed to chemical or physical agents. No differences in occurrence of specific exposures could be detected between cases and controls. Besides, no differences were seen in pesticide or disinfectant exposure among case and control mothers in agricultural occupations. CONCLUSIONS: Occupational exposures of the mother during pregnancy were infrequent and did not seem to play an important part in the aetiology of spina bifida in this study. The association found between spina bifida and maternal agricultural occupations could not be explained by the use of pesticides by the mother or by any other occupational exposure.

Epidemiology, etiologic factors, and prenatal diagnosis of open spinal dysraphism.

The caudal neural tube closes late in the first month after fertilization and failure of it results in myelomeningocele. Epidemiologic studies have shown differences in prevalence at birth based on ethnic-racial backgrounds and geography. Etiologic factors include the drug valproic acid or carbamazepine. Periconceptional folic acid supplementation appears to decrease the prevalence of neural tube defects. Numerous modalities allow for prenatal diagnosis of myelomeningocele. A cesarean section, before rupture of amniotic membranes and onset of labor, decreases the degree of paralysis.

Neural tube defects in Jamaica following Hurricane Gilbert.

An increased incidence of obvious live-birth neural tube defects (i.e., spina bifida cystica and encephalocele) occurred in Jamaica 11 to 18 months after Hurricane Gilbert. The conceptions of the affected babies coincided with a rise in megaloblastic change in sickle cell patients, suggesting a wide-spread drop in dietary folate intake. A detailed history was taken from each of the 17 affected mothers (case subjects) and 51 unaffected mothers (matched control subjects). The case subjects reported a significantly lower mean intake of dietary folate in the periconceptional period (154 micrograms/day) than did the control subjects (254 micrograms/day). The temporary increase in neural tube defects was associated with a diet comparatively low in folate in the periconceptional period, suggesting the dietary level of folate that fails to protect against neural tube defects under natural conditions.