Maternal Obesity and Morbid Obesity: the Risk for Birth Defects in the Offspring
The objective of this study was to assess, in a large data set from Swedish Medical Health Registries, whether maternal obesity and maternal morbid obesity were associated with an increased risk for various structural birth defects.
The study population consisted of 1,049,582 infants born in Sweden from January 1, 1995, through December 31, 2007, with known maternal weight and height data. Women were grouped in six categories of body mass index (BMI) according to World Health Organization classification. Infants with congenital birth defects were identified from three sources: the Swedish Medical Birth Registry, the Register of Birth Defects, and the National Patient Register. Maternal age, parity, smoking, and year of birth were thought to be potential confounders and were included as covariates in the adjusted odds ratio analyses.
Ten percent of the study population was obese. Morbid obesity (BMI > or = 40) occurred in 0.7%. The prevalence of congenital malformations was 4.7%, and the prevalence of relatively severe malformations was 3.2%. Maternal prepregnancy morbid obesity was associated with neural tube defects OR 4.08 (95% CI 1.87-7.75), cardiac defects OR 1.49 (95% CI 1.24-1.80), and orofacial clefts OR 1.90 (95% CI 1.27-2.86). Maternal obesity (BMI > or = 30) significantly increased the risk of hydrocephaly, anal atresia, hypospadias, cystic kidney, pes equinovarus, omphalocele, and diaphragmatic hernia.
The risk for a morbidly obese pregnant woman to have an infant with a congenital birth defect is small, but for society the association is important in the light of the ongoing obesity epidemic.
Available from: Mohammad Jafar Golalipour
- "Our results indicated that rate of NTDs was significantly higher in overweight women compared with normal-weight ones. Several studies showed that being overweight in women was significantly associated with increase of NTDs rate (22-27). "
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ABSTRACT: Background:Neural tube defects (NTDs) including spina bifida and anencephaly are the second most common birth defects with 2.8 per 1000 births in northern Iran.Objectives:This study was conducted to determine the risk factors of neural tube defects in Gorgan, north of Iran.Patients and Methods:This hospital-based, case-control study was carried out on all NTD-affected pregnancies (n = 59) during February 2007 - August 2010, and 160 healthy pregnancies were selected via convenient sampling method in three hospitals in Gorgan, north of Iran. Risk factors including maternal body mass index (BMI), season of birth, gender of the newborn, mother’s age, ethnicity, consanguineous marriage, folic acid consumption, nutrition, habitat, and education, were assessed through interviews with mothers. Univariate and multivariate logistic regression analyses were used to estimate the risks by odds ratios (ORs) and 95% confidence intervals.Results:The multivariate analysis showed that maternal BMI (normal/underweight OR: 0.23, overweight/underweight OR: 0.15, obese/underweight OR: 0.13) and maternal ethnicity (Fars/Sistani OR: 3.49) and maternal nutrition (good/poor OR: 0.46) were significantly correlated with NTDs in the newborns.Conclusions:This study showed that maternal ethnicity, insufficient nutrition, and BMI, were the main risk factors of NTDs in northern Iran.
Available from: Patricia T Jimenez
- "Approximately 60% of women desiring pregnancy in the US are overweight by the BMI criterion, with incidence rising exponentially over the past 15 yrs . Overweight and obese women experience poorer reproductive outcomes than normal weight women, including increased rates of infertility and pregnancy loss, as well as fetal and neonatal problems such as developmental delay and neurological deficits, respectively –. In addition, children born to obese mothers are more likely to acquire childhood obesity. "
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Maternal obesity is associated with poor outcomes across the reproductive spectrum including infertility, increased time to pregnancy, early pregnancy loss, fetal loss, congenital abnormalities and neonatal conditions. Furthermore, the proportion of reproductive-aged woman that are obese in the population is increasing sharply. From current studies it is not clear if the origin of the reproductive complications is attributable to problems that arise in the oocyte or the uterine environment.
We examined the developmental basis of the reproductive phenotypes in obese animals by employing a high fat diet mouse model of obesity. We analyzed very early embryonic and fetal phenotypes, which can be parsed into three abnormal developmental processes that occur in obese mothers. The first is oocyte meiotic aneuploidy that then leads to early embryonic loss. The second is an abnormal process distinct from meiotic aneuploidy that also leads to early embryonic loss. The third is fetal growth retardation and brain developmental abnormalities, which based on embryo transfer experiments are not due to the obese uterine environment but instead must be from a defect that arises prior to the blastocyst stage.
Our results suggest that reproductive complications in obese females are, at least in part, from oocyte maternal effects. This conclusion is consistent with IVF studies where the increased pregnancy failure rate in obese women returns to the normal rate if donor oocytes are used instead of autologous oocytes. We postulate that preconceptional weight gain adversely affects pregnancy outcomes and fetal development. In light of our findings, preconceptional counseling may be indicated as the preferable, earlier target for intervention in obese women desiring pregnancy and healthy outcomes.
Available from: Perrie F O'Tierney-Ginn
- "While some of these drugs are essential, the use of drugs during pregnancy is discouraged by the medical community due to the potential harmful effects of exogenous chemicals on the embryo and fetus. Structural defects (teratogenicity ), preterm birth, and altered birth weight are well described detrimental outcomes that are associated with maternal use of drugs  . There is increasing evidence that the use of drugs can lead to pathophysiological changes that increase vulnerability for diseases later in life  . "
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ABSTRACT: Cytochrome P4501A1 (CYP1A1), an important drug metabolizing enzyme, is expressed in human placenta throughout gestation as well as in fetal liver. Obesity, a chronic inflammatory condition, is known to alter CYP enzyme expression in non-placental tissues. In the present study, we test the hypothesis that maternal obesity alters the distribution of CYP1A1 activity in feto-placental unit. Placentas were collected from non-obese (BMI < 30) and obese (BMI > 30) women at term. Livers were collected from gestation day 130 fetuses of non-human primates fed either control diet or high-fat diet (HFD). Cytosol and microsomes were collected using differential centrifugation, and incubated with 7-ethoxyresorufin. The CYP1A1 specific activity (pmoles of resorufin formed/min/mg of protein) was measured at excitation/emission wavelength of 530/590 nm. Placentas of obese women had significantly reduced microsomal CYP1A1 activity compared to non-obese women (0.046 vs. 0.082; p < 0.05); however no such effect was observed on cytosolic activity. Similarly, fetal liver from HFD fed mothers had significantly reduced microsomal CYP1A1 activity (0.44 ± 0.04 vs. 0.20 ± 0.10; p < 0.05), with no significant difference in cytosolic CYP1A1 activity (control, 1.23 ± 0.20; HFD, 0.80 ± 0.40). Interestingly, multiple linear regression analyses of placental efficiency indicate cytosolic CYP1A1 activity is a main effect (5.67 ± 2.32 (β ± SEM); p = 0.022) along with BMI (-0.57 ± 0.26; p = 0.037), fetal gender (1.07 ± 0.26; p < 0.001), and maternal age (0.07 ± 0.03; p = 0.011). In summary, while maternal obesity affects microsomal CYP1A1 activity alone, cytosolic activity along with maternal BMI is an important determinant of placental efficiency. Together, these data suggest that maternal lifestyle could have a significant impact on CYP1A1 activity, and hints at a possible role for CYP1A1 in feto-placental growth and thereby well-being of fetus.
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