Sex differences in the prevalence of congenital anomalies: a population-based study

BACKGROUND: Limited data is available concerning the sex distribution of various congenital anomaly subtypes. This study investigated sex differences in the prevalence of congenital anomalies, overall and by subtype, using high quality population‐based data from the North of England. METHODS: Information on congenital anomalies occurring among singleton pregnancies during 1985–2003 were extracted from the Northern Congenital Abnormality Survey (NorCAS). Anomalies were categorized by groups, subtypes, and syndromes according to the European Surveillance of Congenital Anomalies guidelines. Relative risks (RRs) comparing the prevalences in males to that in females were calculated for a range of congenital anomaly subtypes. RESULTS: A total of 12,795 eligible cases of congenital anomaly were identified during the study period, including 7019 (54.9%) males and 5776 (45.1%) females. Overall, male fetuses were significantly more prevalent in pregnancies affected by a congenital anomaly than female fetuses (RR, male vs. female = 1.15; 95% confidence interval [CI], 1.11–1.19), but there was significant heterogeneity between subtypes (p < 0.001). Forty‐four of 110 (40%) unique subtypes were at least 40% more prevalent in males than females, with affected subtypes occurring across all major anomaly groups. Thirteen of 110 (12%) unique subtypes were at least 40% more prevalent in females than males, but the female‐biased RR of a neural tube defect was less pronounced than previously reported (RR = 0.84; 95% CI, 0.73–0.95). CONCLUSION:This study adds to the growing evidence of sex‐specific differences in the prevalence of a wide range of congenital anomaly subtypes. Birth Defects Research (Part A), 2011. © 2011 Wiley‐Liss, Inc.     

Maternal diabetes and congenital anomalies in South Australia 1986-2000: a population-based cohort study

BACKGROUND: This study examined the risk of congenital anomalies in infants born in South Australia to women with maternal diabetes in a population-based cohort study of births over a 15-year period, 1986-2000. Differences in the reporting, recording, and diagnosis of pre-existing diabetes mellitus, gestational diabetes mellitus, and impaired glucose tolerance make comparisons between studies difficult. In order to compare published research, details of research methods and analytic approaches are required to understand the potential confounding, bias, and effect modification that may occur. METHODS: Data on congenital anomalies from the South Australian Birth Defects Register were linked to birth data from the Pregnancy Outcome Statistics Unit of the South Australian Department of Health. This enabled information on congenital anomalies to be linked to pregnancy details, including diabetes status. RESULTS: Between 1986 and 2000, the prevalence of congenital anomalies in the infants of mothers with pre-existing diabetes mellitus, gestational diabetes mellitus, or impaired glucose tolerance was significantly higher than in the total population; relative risk = 2.01 (1.66-2.43) and 1.19 (1.08-1.31), respectively. This increased prevalence was not modified by adjustments for maternal age, ethnicity, or other demographic factors, nor did the rate change over the 15 years of the study period. CONCLUSIONS: The prevalence of congenital anomalies was found to be significantly higher in the infants of mothers with maternal diabetes. Larger population-based studies are needed to determine which anomalies are involved and how their occurrence can be reduced.     

Prevalence of esophageal atresia among 18 international birth defects surveillance programs

BACKGROUND: The prevalence of esophageal atresia (EA) has been shown to vary across different geographical settings. Investigation of geographical differences may provide an insight into the underlying etiology of EA. METHODS: The study population comprised infants diagnosed with EA during 1998 to 2007 from 18 of the 46 birth defects surveillance programs, members of the International Clearinghouse for Birth Defects Surveillance and Research. Total prevalence per 10,000 births for EA was defined as the total number of cases in live births, stillbirths, and elective termination of pregnancy for fetal anomaly (ETOPFA) divided by the total number of all births in the population. RESULTS: Among the participating programs, a total of 2943 cases of EA were diagnosed with an average prevalence of 2.44 (95% confidence interval [CI], 2.35–2.53) per 10,000 births, ranging between 1.77 and 3.68 per 10,000 births. Of all infants diagnosed with EA, 2761 (93.8%) were live births, 82 (2.8%) stillbirths, 89 (3.0%) ETOPFA, and 11 (0.4%) had unknown outcomes. The majority of cases (2020, 68.6%), had a reported EA with fistula, 749 (25.5%) were without fistula, and 174 (5.9%) were registered with an unspecified code. CONCLUSIONS: On average, EA affected 1 in 4099 births (95% CI, 1 in 3954–4251 births) with prevalence varying across different geographical settings, but relatively consistent over time and comparable between surveillance programs. Findings suggest that differences in the prevalence observed among programs are likely to be attributable to variability in population ethnic compositions or issues in reporting or registration procedures of EA, rather than a real risk occurrence difference. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.     

Ticks (Ixodidae) on humans in South America

Twenty eight species of Ixodidae have been found on man in South America (21 Amblyomma, 1 Boophilus, 2 Dermacentor, 2 Haemaphysalis, 1 Ixodes and 1 Rhipicephalus species). Most of them are rarely found on man. However, three species frequently parasitize humans in restricted areas of Argentina (A. neumanni reported from 46 localities), Uruguay (A. triste from 21 sites) and Argentina–Brazil (A. parvum from 27 localities). The most widespread ticks are A. cajennense (134 localities in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela), A. ovale (37 localities in Argentina, Brazil, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela) and A. oblongoguttatum (28 sites in Brazil, Colombia, French Guiana, Guyana, Suriname and Venezuela). Amblyomma aureolatum (18 localities in Argentina, Brazil, French Guiana and Paraguay), A. cajennense, and A. triste are vectors of rickettsioses to man in South America. A better understanding of the respective roles of these and other tick species in transmitting pathogens to humans will require further local investigations. Amblyomma ticks should be the main subjects of these studies followed by species of Boophilus, Dermacentor, Haemaphysalis and Rhipicephalus species. In contrast with North America, Europe and Asia, ticks of the genus Ixodes do not appear to be major players in transmitting diseases to human. Indeed, there is only one record of an Ixodes collected while feeding on man for all South America.     

Birth rate and mortality rate of infants with congenital malformations of the limbs in the Awajishima free-ranging group of Japanese monkeys (Macaca fuscata)

The birth rate and mortality rate of infants with congenital malformations of the limbs were examined in the Awajishima free-ranging group of Japanese macaques (Macaca fuscata). Of the 606 infants born between 1978 and 1995, 86 (14.2%) were malformed. The male-female ratio did not differ between malformed and normal infants. Most kin-groups included females who gave birth to malformed infants at least once. The mortality rate within the first year after birth for malformed infants (28.2%) was significantly higher than that for normal infants (10.0%). However, this indicates that more than 70% of malformed infants were able to survive for the first year of life, even though they were unable to cling to their mothers ventrum due to their limb deformities. This finding indicates that maternal care-taking is sufficient to enable malformed infants to survive during the early stages of development and that clinging by the infant is not necessary for the display of maternal care. Am. J. Primatol. 42:225–234, 1997. © 1997 Wiley-Liss, Inc.     

Factors associated with birth rate and live birth rate in multi-male breeding groups of rhesus monkeys

Reproductive records of 284 female rhesus monkeys housed in six multimale corrals at the California Primate Research Center were examined for the birth seasons 1977–1982 to determine possible associations between the probability of birth or live birth and female age, parity, origin, parturition in the previous season, infant birth date, and infant birth date in previous season. Multiple logistic regression analysis was used to identify and quantitate the effects of factors on the probability of birth or live birth, while controlling for the possibly confounding effects of other factors in the model. Females who had infants early in the previous season were 2.5 times as likely to give birth as those who had infants late in the previous season. Females with two or three previous births were 2.1 times as likely to give birth, and those with four or five previous births were 6.7 times as likely to give birth as were females with no or one previous birth. Controlling for other factors (age, parity, and timing of birth in the previous season), corralborn females were 3.3 times as likely to give birth as either wild-caught or domestic-born monkeys not native to the corrals. Domestic-born females who were not corral natives were 0.3 times as likely to have live births as wild-caught females. Births late in the season were 1.8 times as likely to result in live infants as births early in the season.     

Association of paternal age with prevalence of selected birth defects

BACKGROUND: Unlike maternal age, the effect of paternal age on birth defect prevalence has not been well examined. We used cases from the Texas birth defect registry, born during 1996-2002, to evaluate the association of paternal age with the prevalence of selected structural birth defects. METHODS: Poisson regression was used to calculate prevalence ratios (PRs) and 95% confidence intervals (CIs) associated with paternal age for each birth defect, adjusting for maternal age, race/ethnicity, and parity. RESULTS: Relative to fathers ages 25-29 years, fathers 20-24 years of age were more likely to have offspring with gastroschisis (PR 1.47, 95% CI: 1.12-1.94), and fathers 40+ years old were less likely to have offspring with trisomy 13 (PR 0.40, 95% CI: 0.16-0.96). No association was seen between paternal age and prevalence of anencephaly and encephalocele. A selection bias was observed for the other birth defects in which cases of younger fathers were more often excluded from study. CONCLUSIONS: In studies of birth defect risk and paternal age, the source of information may affect the validity of findings.     

First Quaternary fossil record of Polyplacophorans from southern South America

A diverse assemblages of well-preserved polyplacophoran shell plates is present in Holocene marine deposits along the Beagle Channel, Tierra del Fuego (54°S). They represent the first fossil Quaternary report of polyplacophorans from southern South America. The taxa include Callochiton puniceus (Couthouy MS, Gould), Plaxiphora aurata (Spalowsky), Plaxiphora sp., Tonicia atrata (Sowerby), Tonicia calbucensis Plate, Tonicia chilensis (Frembly), and Tonicia lebruni de Rochebrune. The presence of these taxa in a transitory area between the Atlantic and the Pacific oceans suggests that, in the recent past, the Beagle Channel acted as a path that facilitated faunal dispersion between the two oceans. These records also show an apparent stability of these faunas over a period of several thousand years (from ca. 7500 years BP to present).