What links stillbirth and obesity?

September 2, 2015

A new study examines what factors of obesity can increase the risk of stillbirth. Plus: The number of black women with BRCA mutations may be higher than previously thought. And, does prematurity increase the risk of ADHD?

Maternal obesity is known to be an important, modifiable cause of stillbirth and a new study suggests that there may be multiple reasons why the two conditions are linked Published in The American Journal of Clinical Nutrition, the findings are from a case-cohort study by investigators from Magee-Womens Research Institute and McGill University.

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Supported by the National Institutes of Health, the researchers randomly selected 1829 singleton deliveries from a possible 68,437 eligible deliveries at Magee-Womens Hospital in Pittsburgh from 2003 to 2010. They augmented the sample with all remaining stillbirth cases for a total of 658. Probable causes of the stillbirth were classified based on probably cause(s) of death, including maternal medical conditions, obstetric complications, fetal abnormalities, placental diseases, and infection. Clinical experts reviewed medical records, placental tissue slides and pathology reports, and fetal postmortem reports of all stillbirths.

The rate of stillbirth among lean mothers was 7.7 per 1000 live-born and stillborn infants versus 10.6 per 1000 live-born and stillborn infants in overweight mothers. Rates were even higher among the obese and severely obese mothers: 13.9 and 17.3 per 1000 live-born and stillborn infants, respectively.

Women who were severely obese had a two-fold risk of stillbirth in comparison to lean women; risk was just slightly less in obese women. The researchers found an association between maternal obesity and severe obesity and stillbirths from umbilical cord abnormalities, fetal anomalies, hypertension, and placental diseases. Body mass index was found to not be related to placental abruption, obstetric conditions, or infection.

The researchers concluded that a multitude of mechanisms appear to tie obesity to stillbirth. They believe that targeting hypertension and placental diseases could be the best interventions to reduce the risk of stillbirth in obese mothers.

NEXT: BRCA mutation more common in black women than thought

 

BRCA mutation more common in some black women than previously thought

A mutation in a gene that is associated with increased risk of breast or ovarian cancer may be more common in some women than researchers previously believed. The findings, by investigators from the H. Lee Moffitt Cancer Center & Research Institute, point to a potential need to test more young black women for BRCA mutations-even those with no close relatives with breast or ovarian cancer.

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Published in Cancer, the results are from a population-based sample of black women aged 50 or younger who were diagnosed with invasive breast cancer between 2009 and 2012. The participants received genetic counseling, completed a study questionnaire, and consented to release of their medical records. Saliva sample samples from them were subjected to BRCA sequencing and large rearrangement testing through multiplex ligation-dependent probe amplification.

Of the 396 women for whom DNA samples were evaluated, 49 (12.4%) were found to have a mutation in BRCA1 or BRCA2. Eight recurrent mutations accounted for 49% of all pathogenic variants. More than 40% of the women with the mutations had no close relatives with breast ovarian cancer, which the researchers said suggests that family history alone may not identify those at risk of carrying a BRCA mutation.

“The prevalence of BRCA mutations among the Florida-based sample of young black women with breast cancer in the current study,” the authors said, “exceeds that previously reported for non-Hispanic white women. It is appropriate to recommend BRCA testing in all young black women with invasive breast cancer.” 

NEXT: A look at prematurity's impact on ADHD risk

 

Does prematurity increase ADHD risk?

A new population study seems to indicate that risk of attention-deficit/hyperactivity disorder (ADHD) is affected by prematurity and poor fetal growth. The findings, the authors say, show that every gestational week makes a difference to a child’s neurodevelopment.

Researchers used data from the Finnish nationwide researchers and the Finnish Medical Birth Register to identify singleton infants born between January 1, 1991, and December 31, 2005 who were diagnosed with ADHD by December 31, 2011. The average age at diagnosis with ADHD was 7.6 years and 84% of those found to have the condition were boys.

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The case-control study included 10,321 patients who were diagnosed with ADHD according to the International Classification of Diseases and 38,355 controls who were matched by gender and data and place of birth. The association between gestational age, weight for gestational age, and ADHD were examined with conditional logistic regression.

The investigators found that with each declining week of gestation, risk of ADHD increased. The adjusted odds ratio (OR) at week 25 was 5.77 (95% confidence interval [CI], 1.68 - 19.83), compared with 3.55 (95% CI, 2.02 - 6.23) at week 30 and 1.41 (95% CI, 1.12 - 1.78) at week 38. A declining albeit persistent risk was seen at weeks 37 (OR, 1.31; 95% CI, 1.16 - 1.47) and 38 (OR, 1.12; 95% CI, 1.03 - 1.22).

Infants who were more than 2 standard deviations below the average gestational weight had nearly double the risk of an ADHD diagnosis, after adjusting for confounders. On the other end of the spectrum, those who were born more than 2 standard deviations above average gestational weight also had a 1.21-fold (95% CI, 1.05 - 1.40-fold) greater risk.

The researchers concluded that each gestational week has a significant impact on a fetus’s neurodevelopment and the child’s risk for ADHD.