Obesity and stillbirth

Racial and Ethnic Disparities in Stillbirth among Pregnant Women with Obesity

OBJECTIVE

The aim of this study was to examine the relationship between obesity and risk of stillbirth among pregnant women with obesity in the United States, with a focus on racial and ethnic disparities.

STUDY DESIGN

We conducted a retrospective cross-sectional analysis of birth and fetal data from the 2014 to 2019 National Vital Statistics System (N = 14,938,384 total births) to examine associations between maternal body mass index (BMI) and risk of stillbirth. Cox's proportional hazards regression model was used to compute adjusted hazard ratios (HR) as a measure of risk of stillbirth in relation to maternal BMI.

RESULTS

The stillbirth rate was 6.70 per 1,000 births among women with prepregnancy obesity, while the stillbirth rate among women with a normal (nonobese) prepregnancy BMI was 3.85 per 1,000 births. The risk of stillbirth was greater among women with obesity compared with women without obesity (HR: 1.39; 95% confidence interval [CI]: 1.37-1.41). Compared with non-Hispanic (NH) Whites, women identifying as NH-other (HR: 1.66; 95% CI: 1.61-1.72) and NH-Black (HR: 1.31; 95% CI: 1.26-1.35) were at higher risk of stillbirth, while Hispanic women had a decreased likelihood of stillbirth (HR: 0.38; 95% CI: 0.37-0.40).

CONCLUSION

Obesity is a modifiable risk factor for stillbirth. Public health awareness campaigns and strategies targeting weight management in women of reproductive age and racial/ethnic populations at highest risk for stillbirth, are needed.

KEY POINTS

· Stillbirth rates differ by race and ethnicity.. · Risk of stillbirth was greatest among women with obesity.. · Stillbirth rates rise with ascending prepregnancy BMI..

It is time to explore the impact of length of gestation and fetal health on the human lifespan

A recently proposed principal law of lifespan (PLOSP) proposes to extend the whole human lifespan by elongating different life stages. As the preborn stage of a human being, gestation is the foundation for the healthy development of the human body. The antagonistic pleiotropy (AP) theory of aging states that there is a trade-off between early life fitness and late-life mortality. The question is whether slower development during the gestation period would be associated with a longer lifespan. Among all living creatures, the length of the gestation period is highly positively correlated to the length of the lifespan, although such a correlation is thought to be influenced by the body sizes of different species. While examining the relationship between lifespan length and body size within the same species, dogs exhibit a negative correlation between lifespans and body sizes, while there is no such correlation among domestic cats. For humans, most adverse gestational environments shorten the period of gestation, and their impacts are long-term. While many issues remain unsolved, various developmental features have been linked to the conditions during the gestation period. Given that the length of human pregnancies can vary randomly by as long as 5 weeks, it is worth investigating whether a slow steady healthy gestation over a longer period will be related to a longer and healthier lifespan. This article discusses the potential benefits, negative impacts, and challenges of the relative elongation of the gestation period.

Suboptimal gestational weight gain and neonatal outcomes in low and middle income countries: individual participant data meta-analysis

OBJECTIVE

To estimate the associations between gestational weight gain (GWG) during pregnancy and neonatal outcomes in low and middle income countries.

DESIGN

Individual participant data meta-analysis.

SETTING

Prospective pregnancy studies from 24 low and middle income countries.

MAIN OUTCOME MEASURES

Nine neonatal outcomes related to timing (preterm birth) and anthropometry (weight, length, and head circumference) at birth, stillbirths, and neonatal death.

ANALYSIS METHODS

A systematic search was conducted in PubMed, Embase, and Web of Science which identified 53 prospective pregnancy studies published after the year 2000 with data on GWG, timing and anthropometry at birth, and neonatal mortality. GWG adequacy was defined as the ratio of the observed maternal weight gain over the recommended weight gain based on the Institute of Medicine body mass index specific guidelines, which are derived from data in high income settings, and the INTERGROWTH-21st GWG standards. Study specific estimates, adjusted for confounders, were generated and then pooled using random effects meta-analysis models. Maternal age and body mass index before pregnancy were examined as potential modifiers of the associations between GWG adequacy and neonatal outcomes.

RESULTS

Overall, 55% of participants had severely inadequate (<70%) or moderately inadequate (70% to <90%) GWG, 22% had adequate GWG (90-125%), and 23% had excessive GWG (≥125%). Severely inadequate GWG was associated with a higher risk of low birthweight (adjusted relative risk 1.62, 95% confidence interval 1.51 to 1.72; 48 studies, 93 337 participants; τ2=0.006), small for gestational age (1.44, 1.36 to 1.54; 51 studies, 93 191 participants; τ2=0.016), short for gestational age (1.47, 1.29 to 1.69; 40 studies, 83 827 participants; τ2=0.074), and microcephaly (1.57, 1.31 to 1.88; 31 studies, 80 046 participants; τ2=0.145) compared with adequate GWG. Excessive GWG was associated with a higher risk of preterm birth (1.22, 1.13 to 1.31; 48 studies, 103 762 participants; τ2=0.008), large for gestational age (1.44, 1.33 to 1.57; 47 studies, 90 044 participants; τ2=0.009), and macrosomia (1.52, 1.33 to 1.73; 29 studies, 68 138 participants; τ2=0) compared with adequate GWG. The direction and magnitude of the associations between GWG adequacy and several neonatal outcomes were modified by maternal age and body mass index before pregnancy.

CONCLUSIONS

Inadequate and excessive GWG are associated with a higher risk of adverse neonatal outcomes across settings. Interventions to promote optimal GWG during pregnancy are likely to reduce the burden of adverse neonatal outcomes, however further research is needed to assess optimal ranges of GWG based on data from low and middle income countries.

Defining poor growth and stillbirth risk in pregnancy for infants of mothers with overweight and obesity

BACKGROUND

Mothers who are obese carry heavier fetuses and have lower rates of small for gestational age (<10th birthweight centile) infants. However, their infants may be growth-restricted (with an increased risk of stillbirth) at a higher birthweight centile compared with infants from healthy-weight women.

OBJECTIVE

This study aimed to quantify the birthweight centile at which the risk of stillbirth in infants born to obese women equaled that of <10th-centile infants born to healthy-weight women, and clarify the relationship between maternal body mass index, infant size, and stillbirth.

STUDY DESIGN

We conducted a retrospective cohort study on all infants born in Victoria, Australia, from 2009 to 2019 (754,946 cases for analysis). We applied uncustomized birthweight centiles to all infants, and stratified the maternal cohort by body mass index (<20 kg/m2, 20-25 kg/m2, 25-30 kg/m2, 30-35 kg/m2, 35-40 kg/m2, ≥40 kg/m2). For each body mass index category, we assessed proportions of infants born <10th centile and <3rd centile, stillbirth rates among infants of all sizes, and small for gestational age infants. We calculated the stillbirth rate (per 1000) and relative risk (risk of stillbirth if born <10th centile vs >10th centile) for healthy-weight women (body mass index, 20-25 kg/m2). We then determined the birthweight centile for infants born to mothers within other body mass index categories that equaled that rate or risk.

RESULTS

Stillbirth rates increased with increasing maternal body mass index. Infants classified as small for gestational age (<10th centile) from mothers with high body mass index had a higher risk of stillbirth (relative risk, 3.15; 95% confidence interval, 2.22-4.47; for mothers with body mass index ≥40 kg/m2 vs healthy-weight mothers [body mass index, 20-25 kg/m2]). The stillbirth rate (stillborn infants per 1000 births) among <10th-centile infants born to healthy-weight mothers was 7.5 per 1000. The same stillbirth rate was observed at higher birthweight centiles for infants of women with higher body mass index (<18th centile for those with a body mass index of 25-30 kg/m2, <25th centile for body mass index of 30-35 kg/m2, <31st centile for body mass index of 35-40 kg/m2, <41st centile for body mass index of ≥40 kg/m2). The relative risk of stillbirth among small for gestational age infants of healthy-weight mothers was 5.46 (95% confidence interval, 4.65-6.40). The birthweight centile with a comparable relative risk of stillbirth increased with increasing body mass index (<16th centile for women with body mass index of 25-30 kg/m2, <19th centile for body mass index of 30-35 kg/m2, <28th centile for body mass index of 35-40 kg/m2, <30th centile for body mass index ≥40 kg/m2).

CONCLUSION

Obesity affects the relationship between infant size and perinatal mortality. The stillbirth risk observed in <10th-centile infants from healthy-weight mothers occurs at higher birthweight centiles with overweight or obese mothers. Clinicians should be aware that the same infant risk exists at a higher birthweight centile for women with higher body mass index.

Comparison of maternal and fetal health outcomes in the pandemic period of covid-19 with the same last year duration in health centers of second largest city of Iran: A population-based cohort study

Objective

The exact link between COVID-19 pandemic and different adverse outcomes of pregnancy remains unclear. Plus, large-scale research is lacking. In the present study, we aimed to compare the maternal and fetal health outcomes during the COVID-19 pandemic with the same last year duration in Iran.

Design

Two retrospective cohorts (pre-COVID-19 and during COVID-19) were studied. The pre-COVID-19 cohort include pregnant women who had given birth between January 1, 2019 and December 31, 2019. The COVID-19 cohort, who had given birth between January 1, 2020 and December 31, 2020. The characteristics of pregnant women before COVID-19 and during COVID-19 pandemic were compared with Fisher's exact test. Univariate and multivariate log-binomial regression models were used to determine the risk ratios of the impacts of the COVID-19 pandemic on adverse pregnancy outcomes.

Results

Among 128968 women showed that women who had given birth during the pandemic were more likely to be of young age, lower rates of alcohol consumption and smoking, lower weight gain, and higher rates of using synthetic milk for feeding neonates (P < 0.05). Also, the risks of preterm labor were high (cOR 95% CI, 1.13 to 1.31; p < 0.01) and the risk of caesarian were low (cOR 95% CI, 0.95 0.92 to 0.98; p < 0.01) among pregnant women who gave birth during the COVID-19 pandemic compared with those who gave birth before the pandemic.

Conclusions

In summary, we found that during the COVID-19 pandemic there were the higher risks of preterm labor and lower risk of caesarean among pregnant women.

Genetic Risk Factors and Gene-Lifestyle Interactions in Gestational Diabetes

Paralleling the increasing trends of maternal obesity, gestational diabetes (GDM) has become a global health challenge with significant public health repercussions. In addition to short-term adverse outcomes, such as hypertensive pregnancy disorders and fetal macrosomia, in the long term, GDM results in excess cardiometabolic morbidity in both the mother and child. Recent data suggest that women with GDM are characterized by notable phenotypic and genotypic heterogeneity and that frequencies of adverse obstetric and perinatal outcomes are different between physiologic GDM subtypes. However, as of yet, GDM treatment protocols do not differentiate between these subtypes. Mapping the genetic architecture of GDM, as well as accurate phenotypic and genotypic definitions of GDM, could potentially help in the individualization of GDM treatment and assessment of long-term prognoses. In this narrative review, we outline recent studies exploring genetic risk factors of GDM and later type 2 diabetes (T2D) in women with prior GDM. Further, we discuss the current evidence on gene-lifestyle interactions in the development of these diseases. In addition, we point out specific research gaps that still need to be addressed to better understand the complex genetic and metabolic crosstalk within the mother-placenta-fetus triad that contributes to hyperglycemia in pregnancy.

Etiology and evaluation of stillbirth in patients with obesity

OBJECTIVE

Maternal obesity is a risk factor for stillbirth, but whether or not the etiology of stillbirth differs in gravidas with and without obesity is unknown. We categorized stillbirths in a contemporary cohort to test the hypothesis that the etiology of stillbirth is different in gravidas with and without obesity.

METHODS

This retrospective cohort study included all gravidas with a stillbirth ≥20 weeks' gestation between 2010 and 2017 and a normal mid-trimester anatomic survey by ultrasound assessment at a large academic institution. Pregnancies were excluded if delivery data were unavailable, a multifetal gestation was present, or there was an antenatally diagnosed fetal structural or genetic anomaly. Our primary exposure was maternal obesity, defined as a body mass index (BMI) ≥ 30 kg/m² at the time of anatomic survey. Our primary outcome was stillbirth etiology, as classified by the initial causes of fetal death tool from the Stillbirth Collaborative Research Network and includes maternal, obstetric, hematologic, fetal, infectious, placental, other, or unexplained categories. Our secondary outcomes included the evaluation performed on each stillbirth, compliance with the recommended stillbirth evaluation by the American College of Obstetricians and Gynecologists (ACOG), and the percentage of abnormal results for each of the tests ordered for stillbirth evaluation.

RESULTS

Of 118 stillbirths meeting the inclusion criteria, 44 (37.3%) occurred in gravidas with obesity and 74 (62.7%) were in patients without obesity. An obstetric complication was the most commonly identified etiology for stillbirth, found in 40.9% of cases with obesity versus in 29.7% of cases without obesity (aOR 1.09, 95% CI 0.47-2.66). The likelihood of any specific etiology of stillbirth was not significantly different in gravidas of the two weight groups, after controlling for confounders. However, assignment to the unexplained stillbirth category was significantly less common in women with obesity, compared to those without obesity (aOR 0.18, 95% CI 0.05-0.67). There was no difference in testing performed on each stillbirth between the groups. Compliance with the ACOG-recommended diagnostic evaluation for stillbirth was similar in the two groups but was only performed in 10.2% of all cases of stillbirth. Placental pathology was the test most likely to yield an abnormal result in both groups, but the percentage of abnormal results for this and all other tests was the same in the presence and absence of obesity.

CONCLUSION

There is no specific etiology of stillbirth seen in gravidas with obesity, compared to those without obesity, after controlling for maternal confounders. We surmise that the evaluation recommended for stillbirth assessment in the general population is appropriate for stillbirth evaluation in gravidas with obesity. Testing pursued was similar between groups, but compliance with ACOG recommendations for testing after stillbirth was deficient in the cohort. Future work should aim to identify and address barriers to completing the recommended stillbirth evaluation.

Associations between gestational weight gain adequacy and neonatal outcomes in Tanzania

Introduction: Gestational weight gain (GWG) is associated with fetal and newborn health; however, data from sub-Saharan Africa are limited. Methods: We used data from a prenatal micronutrient supplementation trial among a cohort of HIV-negative pregnant women in Dar es Salaam, Tanzania to estimate the relationships between GWG and newborn outcomes. GWG adequacy was defined as the ratio of the total observed weight gain over the recommended weight gain based on the Institute of Medicine body mass index (BMI)-specific guidelines. Newborn outcomes assessed were: stillbirth, perinatal death, preterm birth, low birthweight, macrosomia, small-for-gestational age (SGA), large-for-gestational age (LGA), stunting at birth, and microcephaly. Modified Poisson regressions with robust standard error were used to estimate the relative risk of newborn outcomes as a function of GWG adequacy. Results: Of 7561 women included in this study, 51% had severely inadequate (<70%) or inadequate GWG (70-90%), 31% had adequate GWG (90-125%), and 18% had excessive GWG (≥125%). Compared to adequate GWG, severely inadequate GWG was associated with a higher risk of low birthweight, SGA, stunting at birth, and microcephaly; whereas excessive GWG was associated with a higher risk of LGA and macrosomia. Conclusion: Interventions to support optimal gestational weight gain are needed and are likely to improve newborn outcomes.

Maternal obesity and stillbirth at term; placental pathology-A case control study

OBJECTIVE

The aim was to explore the potential role of the placenta for the risk of stillbirth at term in pregnancies of obese women.

METHODS

This was a case-control study comparing placental findings from term stillbirths with placental findings from live born infants. Cases were singleton term stillbirths to normal weight or obese women, identified in the Stockholm stillbirth database, n = 264 and n = 87, respectively. Controls were term singletons born alive to normal weight or obese women, delivered between 2002-2005 and between 2018-2019. Placentas were compared between women with stillborn and live-born infants, using logistic regression analyses.

RESULTS

A long and hyper coiled cord, cord thrombosis and velamentous cord insertion were stronger risk factors for stillbirth in obese women compared to normal weight women. When these variables were adjusted for in the logistic regression analysis, also adjusted for potential confounders, the odds ratio for stillbirth in obese women decreased from 1.89 (CI 1.24-2.89) to 1.63 (CI 1.04-2.56).

CONCLUSION

Approximately one fourth of the effect of obesity on the risk of stillbirth in term pregnancies is explained by umbilical cord associated pathology.

Pre-pregnancy maternal obesity, macrosomia, and risk of stillbirth: A population-based study

OBJECTIVE

An examination of the synergistic effects of maternal obesity and macrosomia on the risk of stillbirth is lacking. The purpose of this study was to determine the association between fetal macrosomia, maternal obesity, and the risk of stillbirth.

METHODS

This retrospective cross-sectional study used the CDC's Birth Data and Fetal Death Data files for 2014-2017 [n = 10,043,398‬ total births; including 48,799 stillbirths]. The exposure was fetal macrosomia stratified by obesity subtypes (I-III). The outcome was the risk of stillbirth. We also controlled for potential and known confounding factors in adjusted models. Adjusted Relative Risks (ARR) were estimated with log-binomial regression models.

RESULTS

The rate of stillbirth was higher among macrosomic infants born to mothers with obesity compared to those without (6.55 vs. 0.54 per 1000 total births). After controlling for confounding, women with obesity types II and III were at increased risk for stillbirth [Obesity II ARR = 2.37 (2.07-2.72); Obesity III ARR = 9.06 (7.61-10.78)].

CONCLUSIONS FOR PRACTICE

Obesity-related fetal overgrowth is a significant risk factor for stillbirth, especially among women with type II and type III obesity. This finding highlights the need for more effective clinical and public health strategies to address pre-pregnancy obesity and to optimize gestational weight gain.

Association of Overweight and Obesity Development Between Pregnancies With Stillbirth and Infant Mortality in a Cohort of Multiparous Women

OBJECTIVE

To identify the association of newly developed prepregnancy overweight and obesity with stillbirth and infant mortality.

METHODS

We studied subsequent pregnancies of mothers who were normal weight at fertilization of their first identified pregnancy, from a population-based cohort that linked birth registry with death records in Pennsylvania, 2003-2013. Women with newly developed prepregnancy overweight and obesity were defined as those whose body mass index (BMI) before second pregnancy was between 25 and 29.9 or 30 or higher, respectively. Our main outcomes of interest were stillbirth (intrauterine death at 20 weeks of gestation or greater), infant mortality (less than 365 days after birth), neonatal death (less than 28 days after birth) and postneonatal death (29-365 days after birth). Associations of both prepregnancy BMI categories and continuous BMI with each outcome were estimated by nonparametric targeted minimum loss-based estimation and inverse-probability weighted dose-response curves, respectively, adjusting for race-ethnicity, smoking, and other confounders (eg, age, education).

RESULTS

A cohort of 212,889 women were included for infant mortality analysis (192,941 women for stillbirth analysis). The crude rate of stillbirth and infant mortality in these final analytic cohorts were 3.3 per 1,000 pregnancies and 2.9 per 1,000 live births, respectively. Compared with women who stayed at a normal weight in their second pregnancies, those becoming overweight had 1.4 (95% CI 0.6-2.1) excess stillbirths per 1,000 pregnancies. Those becoming obese had 3.6 (95% CI 1.3-5.9) excess stillbirths per 1,000 pregnancies and 2.4 (95% CI 0.4-4.4) excess neonatal deaths per 1,000 live births. There was a dose-response relationship between prepregnancy BMI increases of more than 2 units and increased risk of stillbirth and infant mortality. In addition, BMI increases were associated with higher risks of infant mortality among women with shorter interpregnancy intervals (less than 18 months) compared with longer intervals.

CONCLUSION

Transitioning from normal weight to overweight or obese between pregnancies was associated with an increased risk of stillbirth and neonatal mortality.

Prediction of stillbirth in women with overweight or obesity-A register-based cohort study

OBJECTIVE

To develop a model for prediction of stillbirth after the 28th gestational week in singleton pregnancies of women with overweight or obesity.

METHOD

This is a register-based cohort study. The first trimester screening database including data from 2006 until 2015 was cross-linked with the Swedish Medical Birth Register and the Swedish Register of Total Population. The final study cohort comprised 145,319 pregnancies, out of which 45,859 pregnancies were complicated by overweight or obesity and without pre-gestational diabetes. There were in total 282 stillbirths. Prediction models for stillbirth in pregnancies with overweight or obesity were constructed based on maternal characteristics, pregnancy complications and biochemical markers. Receiver Operating Characteristic (ROC) and area under curve (AUC) were calculated, based on logistic regression analyses.

RESULTS

The prevalence of stillbirth was 1.6/1000 births and 2.6/1000 births in normal weight and overweight/obese women, respectively. The final predictive model had an AUC of 0.69 (95% CI: 0.64-0.74) with a sensitivity of 28% at a 90% fixed specificity.

CONCLUSIONS

It is possible to predict 28% of stillbirths in overweight or obese women, at a false positive rate of 10%. In particular, growth-restricted fetuses are at increased risk of stillbirth.

Disparities in gestational age-specific fetal mortality rates in the United States, 2009-2013

PURPOSE

Although studies have examined overall temporal changes in gestational age-specific fetal mortality rates, there is little information on the current status of racial/ethnic differences. We hypothesize that differences exist between racial/ethnic groups across gestational age and that these differences are not equally distributed.

METHODS

Using the 2009-2013 data from US fetal death and live birth files for non-Hispanic white (NHW); non-Hispanic black (NHB); Hispanic; and American Indian/Alaska Native (AIAN) women, we conducted analyses to examine fetal mortality rates and estimate adjusted prevalence rate ratios and 95% confidence intervals (CIs).

RESULTS

There were lower risks of fetal mortality among NHB women (aPRR = 0.76; 95% CI = 0.71-0.81) and Hispanic women (aPRR = 0.89; 95% CI = 0.83-0.96) compared with NHWs at 22-23 weeks' gestation. For NHB women, the risk was higher starting at 32-33 weeks (aPRR = 1.11; 95% CI = 1.04-1.18) and continued to increase as gestational age increased. Hispanic and AIAN women had lower risks of fetal mortality compared with NHW women until 38-39 weeks.

CONCLUSIONS

Further examination is needed to identify causes of fetal death within the later pregnancy period and how those causes and their antecedents might differ by race and ethnicity.

Maternal exposure to childhood maltreatment and risk of stillbirth

PURPOSE

To determine the association between maternal exposure to childhood maltreatment (CM) and risk of stillbirth (fetal death at or after 20 weeks' gestation).

METHODS

Population-based case-control study from the Stillbirth Collaborative Research Network (SCRN) conducted in 2006-2008, and the follow-up study, SCRN-Outcomes after Study Index Stillbirth (SCRN-OASIS), conducted in 2009 in the United States. Cases (n = 133) included women who experienced a stillbirth, excluding stillbirths attributed to genetic/structural or umbilical cord abnormalities and intrapartum stillbirths. Controls (n = 500) included women delivering a healthy term live birth (excluding births less than 37 weeks gestation, neonatal intensive care unit admission, or death). CM exposure was measured using the Childhood Trauma Questionnaire, administered during the SCRN-OASIS study. Dichotomized scores for five subscales of CM (physical abuse, physical neglect, emotional abuse, emotional neglect, and sexual abuse) and an overall measure of CM exposure were analyzed using logistic regression.

RESULTS

Generally, there was no association between CM and stillbirth, except for the emotional neglect subscale (OR: 1.93; 95% CI: 1.17, 3.19).

CONCLUSIONS

Childhood neglect is understudied in comparison to abuse and should be included in the future studies of associations between CM and pregnancy outcomes, including stillbirth.

Risk of stillbirth in pregnant women with obesity in the United Kingdom

BACKGROUND

The stillbirth rate in the United Kingdom (UK) is approximately 3.5-4 per 1000 births. The country has one of the highest stillbirth rates in Europe, constituting a substantial portion of the UK perinatal death rate, which was estimated in 2013 at 6.7 deaths per 1000 births.

AIM

To analyse the risk of stillbirth in pregnant women with and without increased BMI in the United Kingdom (UK).

DESIGN AND SETTING

Retrospective study based on Disease Analyzer database (IMS Health).

METHOD

A total of 44,060 pregnant women with or without an increased BMI who gave birth to a single child were examined using a Disease Analyzer database that included 102 general practices. Selected patients were observed for a period of at least 10 months between January 1994 and December 2013. Standard BMI ranges were considered: 18.5-24.9 (normal weight), 25-29.9 (overweight), 30-39.9 (class I and class II obese), 40-49.9 (class III) and over 50 (class IV). Multivariate logistic models were used to estimate the relationship between increasing BMI and the rate of stillbirth adjusted for demographic data and co-morbidities.

RESULTS

BMI increase was associated with an increase in stillbirth OR, from 1.37 (95% CI: 1.02-1.85) in the overweight group to 5.04 (95% CI: 1.79-14.07) in the group of pregnant women with a BMI higher than or equal to 50.

CONCLUSIONS

Pregnant women with obesity and even moderate overweight exhibit an increased risk of stillbirth in UK primary care practices over 20 years.

Hyperpolarized [1-(13) C]pyruvate MRI for noninvasive examination of placental metabolism and nutrient transport: A feasibility study in pregnant guinea pigs

PURPOSE

To test the feasibility of hyperpolarized [1-(13) C]pyruvate magnetic resonance imaging (MRI) for noninvasive examination of guinea pig fetoplacental metabolism and nutrient transport.

MATERIALS AND METHODS

Seven pregnant guinea pigs with a total of 30 placentae and fetuses were anesthetized and scanned at 3T. T1 -weighted (1) H images were obtained from the maternal abdomen. An 80 mM solution of hyperpolarized [1-(13) C]pyruvate (hereafter referred to as pyruvate) was injected into a vein in the maternal foot. Time-resolved 3D (13) C images were acquired starting 10 seconds after the beginning of bolus injection and every 10 seconds after to 50 seconds. The pregnant guinea pigs were recovered after imaging. Regions of interest (ROIs) were drawn around the maternal heart and each placenta and fetal liver in all slices in the (1) H images. These ROIs were copied to the (13) C images and were used to calculate the sum of the pyruvate and lactate signal intensities for each organ. The signal intensities were normalized by the volume of the organ and the maximum signal in the maternal heart.

RESULTS

No adverse events were observed in the pregnant guinea pigs and natural pupping occurred at term (∼68 days). Pyruvate signal was observed in all 30 placentae, and lactate, a by-product of pyruvate metabolism, was also observed in all placentae. The maximum pyruvate and lactate signals in placentae occurred at 20 seconds. In addition to the observation of pyruvate and lactate signals in the placentae, both pyruvate and lactate signals were observed in all fetal livers. The maximum pyruvate and lactate signals in the fetal livers occurred at 10 seconds and 20 seconds, respectively.

CONCLUSION

This work demonstrates the feasibility of using hyperpolarized [1-(13) C]pyruvate MRI to noninvasively examine fetoplacental metabolism and transport of pyruvate in guinea pigs. Hyperpolarized (13) C MRI may provide a novel method for longitudinal studies of fetoplacental abnormalities.