The impact of isolated obesity compared with obesity and other risk factors on risk of stillbirth: a retrospective cohort study.

BACKGROUND: Maternal obesity is associated with stillbirth, but uncertainty persists around the effects of higher obesity classes. We sought to compare the risk of stillbirth associated with maternal obesity alone versus maternal obesity and additional or undiagnosed factors contributing to high-risk pregnancy. METHODS: We conducted a retrospective cohort study using the Better Outcomes Registry and Network (BORN) for singleton hospital births in Ontario between 2012 and 2018. We used multivariable Cox proportional hazard regression and logistic regression to evaluate the relationship between prepregnancy maternal body mass index (BMI) class and stillbirth (reference was normal BMI). We treated maternal characteristics and obstetrical complications as independent covariates. We performed mediator analyses to measure the direct and indirect effects of BMI on stillbirth through major common-pathway complications. We used fully adjusted and partially adjusted models, representing the impact of maternal obesity alone and maternal obesity with other risk factors on stillbirth, respectively. RESULTS: We analyzed data on 681 178 births between 2012 and 2018, of which 1956 were stillbirths. Class I obesity was associated with an increased incidence of stillbirth (adjusted hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.35-1.78). This association was stronger for class III obesity (adjusted HR 1.80, 95% CI 1.44-2.24), and strongest for class II obesity (adjusted HR 2.17, 95% CI 1.83-2.57). Plotting point estimates for odds ratios, stratified by gestational age, showed a marked increase in the relative odds for stillbirth beyond 37 weeks' gestation for those with obesity with and without other risk factors, compared with those with normal BMI. The impact of potential mediators was minimal. INTERPRETATION: Maternal obesity alone and obesity with other risk factors are associated with an increased risk of stillbirth. This risk increases with gestational age, especially at term.

Relationship Between Gestational Weight Gain and Health Service Utilization in Early Childhood: A Retrospective Cohort Study.

OBJECTIVE: Gestational weight gain (GWG) outside recommended ranges can negatively impact both the woman and child. The long-term effects of below-recommended or above-recommended GWG on the child are unclear. METHODS: This retrospective cohort study used a population-based birth registry of 258,005 live births to evaluate the relationship between maternal GWG and paediatric health service use. RESULTS: The results suggest below recommended GWG in underweight women in particular is associated with an increased rate of hospitalizations and specialist visits for the child in the first 24 months. CONCLUSION: Findings indicate that GWG may impact paediatric outcomes in ways that depend on pre-pregnancy body mass index, as derived from maternal height and weight measures.

Gestational weight loss and fetal growth in uncomplicated pregnancies among women with obesity: a population-based retrospective cohort study.

OBJECTIVE: The impact of gestational weight loss (GWL) on fetal growth among women with obesity remains unclear. This study aimed to examine the association between weight loss during pregnancy among women with body mass index (BMI) ≥ 30 kg/m2 and the risk of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) neonates. METHODS: We conducted a retrospective, population-based cohort study of women with pre-pregnancy obesity that resulted in a singleton live birth in 2012-2017, using birth registry data in Ontario, Canada. Women with pregnancy complications or health conditions which could cause weight loss were excluded. GWL is defined as negative gestational weight change (≤0 kg). The association between GWL and fetal growth was estimated using generalized estimating equation models and restricted cubic spline regression analysis. Stratified analysis was conducted by obesity class (I:30-34.9 kg/m2, II:35-39.9 kg/m2, and III + : ≥40 kg/m2). RESULTS: Of the 52,153 eligible women who entered pregnancy with a BMI ≥ 30 kg/m2, 5.3% had GWL. Compared to adequate gestational weight gain, GWL was associated with an increased risk of SGA neonates (aRR:1.45, 95% CI: 1.30-1.60) and a decreased risk of LGA neonates (aRR: 0.81, 95% CI:0.73-0.93). Non-linear L-shaped associations were observed between gestational weight change and SGA neonates, with an increased risk of SGA observed with increased GWL. On the contrary, non-linear S-shaped associations were observed between gestational weight change and LGA neonates, with a decreased risk of LGA observed with increased GWL. Similar findings were observed from the stratified analysis by obesity class. CONCLUSION: These findings highlight that GWL in women with obesity may increase the risk of SGA neonates but reduce the risk of LGA neonates. Recommendations of GWL for women with obesity should be interpreted with caution.

Maternal weight and paediatric health use: mediating role of adverse birth outcomes: a retrospective cohort study.

BACKGROUND: Maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) above or below recommendations have been associated with increased paediatric health service utilization as well as increased risk of adverse birth outcomes, including small for gestational age (SGA) and preterm birth (PTB). SGA and PTB are associated with numerous adverse health outcomes in the child, including delayed growth, motor and cognitive impairment. Previous research has identified birth weight and gestational age on the causal pathway in the association between maternal pre-pregnancy BMI and child hospital admissions, there are no studies to date to quantify this relationship across other areas of health service utilization, nor the impact of gestational weight gain. This study aimed to assess if SGA or PTB partially explain the association between maternal weight and paediatric health service utilization. METHODS: The study population consisted of all women who delivered a singleton, live infant in Ontario between 2012 and 2014, and was assembled from data contained in the provincial birth registry. Health service utilization over the first 24 months following birth was examined by linking data from the registry with other provincial health administrative databases housed at ICES. The mediating roles of PTB and SGA were assessed using the Baron-Kenny method and causal mediation analysis. RESULTS: A total of 204,162 infants were included in the analysis of maternal pre-pregnancy BMI and 171,127 infants were included in the GWG analysis. The small magnitude of association between maternal BMI and paediatric health service utilization impacted our ability to estimate the indirect effect of maternal BMI through adverse birth outcomes (adjusted indirect effect = 0.00). 56.7% of the association between below recommended GWG and increased hospitalizations was attributed to PTB, while 6.8% of the association was attributed to SGA. CONCLUSION: Paediatric hospitalizations may be partially attributable to PTB and SGA in children born to mothers with below-recommended GWG. However, maternal weight also appears to be related to increased paediatric health service utilization independent of PTB and SGA.

Examining the role of pre-pregnancy weight and gestational weight gain in allergic disease development among offspring: A population-based cohort study in Ontario, Canada.

BACKGROUND: Studies suggest maternal weight and weight gain during pregnancy may influence foetal immunological development. However, their role in the aetiology of allergic disease is unclear. OBJECTIVES: We sought to examine the impact of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on the incidence of four common paediatric allergic diseases. METHODS: We conducted a retrospective, population-based cohort study of all singleton live births in Ontario, Canada between 2012 and 2014, using maternal-newborn records from the provincial birth registry linked with health administrative databases. Neonates were followed up to 7 years for anaphylaxis, asthma, dermatitis and rhinitis, identified through validated algorithms based on healthcare encounters. We multiply imputed missing data and employed Cox proportional-hazards models to calculate adjusted hazard ratios (aHR) with 95% confidence intervals (CI). To test the robustness of our findings, we also conducted several sensitivity analyses, including probabilistic bias analyses for exposure and outcome misclassification. All methods were prespecified in a published protocol. RESULTS: Of the 248,017 infants followed, 52% were born to mothers with a pre-pregnancy BMI in the normal range and only 19% were born to mothers with adequate weight gain during pregnancy. Incidence rates (per 100,000 person-days) for anaphylaxis, asthma, dermatitis and rhinitis were 0.22, 6.80, 12.41 and 1.54, respectively. Compared with normal BMI, maternal obesity was associated with increased hazards of asthma in offspring (aHR 1.08, 95% CI 1.05, 1.11), but decreased hazards of anaphylaxis (aHR 0.83, 95% CI 0.69, 0.99) and dermatitis (aHR 0.97, 95% CI 0.94, 0.99). In contrast, maternal underweight was associated with increased hazards of dermatitis (aHR 1.06, 95% CI 1.02, 1.10). We found no associations between pre-pregnancy BMI and rhinitis or GWG and any allergic outcome, and no evidence of effect measures modification by infant sex. CONCLUSIONS: These findings provide support for the involvement of maternal pre-pregnancy BMI in paediatric allergic disease development.

Exploring weight bias internalization in pregnancy.

BACKGROUND: Recent research has shown that pregnant individuals experience weight stigma throughout gestation, including negative comments and judgement associated with gestational weight gain (GWG). Weight bias internalization (WBI) is often a result of exposure to weight stigma and is detrimental to biopsychological health outcomes. The purpose of this study was to explore WBI in pregnancy and compare scores based on maternal weight-related factors including pre-pregnancy body mass index (BMI), obesity diagnosis and excessive GWG. METHODS: Pregnant individuals in Canada and USA completed a modified version of the Adult Weight Bias Internalization Scale. Self-reported pre-pregnancy height and weight were collected to calculate and classify pre-pregnancy BMI. Current weight was also reported to calculate GWG, which was then classified as excessive or not based on Institute of Medicine (2009) guidelines. Participants indicated if they were diagnosed with obesity by a healthcare provider. Inferential analyses were performed comparing WBI scores according to pre-pregnancy BMI, excessive GWG, and obesity diagnosis. Significance was accepted as p < 0.05 and effect sizes accompanied all analyses. RESULT: 336 pregnant individuals completed the survey, with an average WBI score of 3.9 ± 1.2. WBI was higher among those who had a pre-pregnancy BMI of obese than normal weight (p = 0.04, η2 = 0.03), diagnosed with obesity than not diagnosed (p < 0.001, Cohen's d = 1.3), and gained excessively versus not (p < 0.001, Cohen's d = 1.2). CONCLUSIONS: Pregnant individuals who have a higher BMI, obesity and gain excessively may experience WBI. Given that weight stigma frequently occurs in pregnancy, effective person-oriented strategies are needed to mitigate stigma and prevent and care for WBI.

Evaluating the correlation between amniotic fluid volume and estimated fetal weight in healthy pregnant women.

OBJECTIVES: The establishment of cut-offs for normal amniotic fluid volume (AFV) is valuable to predict perinatal outcomes. However, the most common methods to measure AFV are not accurate enough. It is important to understand factors that may be able to increase the accuracy of the calculation of AFV cut-off values. The objective of this study was to verify the correlation between AFV and estimated fetal weight (EFW). METHODS: Records from almost 7,000 patients between 2012 and 2017 were accessed through hospital databases. The AFV measurements included in our analysis were obtained using the maximum vertical pocket technique. RESULTS: AFV was positively correlated with EFW in the overall, male and female samples; however, the magnitude of the association was small (0.1

Birth outcomes following cesarean delivery on maternal request: a population-based cohort study.

BACKGROUND: Data on the effect of cesarean delivery on maternal request (CDMR) on maternal and neonatal outcomes are inconsistent and often limited by inadequate case definitions and other methodological issues. Our objective was to evaluate the trends, determinants and outcomes of CDMR using an intent-to-treat approach. METHODS: We designed a population-based retrospective cohort study using data on low-risk pregnancies in Ontario, Canada (April 2012-March 2018). We assessed temporal trends and determinants of CDMR. We estimated the relative risks for component and composite outcomes used in the Adverse Outcome Index (AOI) related to planned CDMR compared with planned vaginal delivery using generalized estimating equation models. We compared the Weighted Adverse Outcome Score (WAOS) and the Severity Index (SI) across planned modes of delivery using analysis of variance. RESULTS: Of 422 210 women, 0.4% (n = 1827) had a planned CDMR and 99.6% (n = 420 383) had a planned vaginal delivery. The prevalence of CDMR remained stable over time at 3.9% of all cesarean deliveries. Factors associated with CDMR included late maternal age, higher education, conception via in vitro fertilization, anxiety, nulliparity, being White, delivery at a hospital providing higher levels of maternal care and obstetrician-based antenatal care. Women who planned CDMR had a lower risk of adverse outcomes than women who planned vaginal delivery (adjusted relative risk 0.42, 95% confidence interval [CI] 0.33 to 0.53). The WAOS was lower for planned CDMR than planned vaginal delivery (mean difference -1.28, 95% CI -2.02 to -0.55). The SI was not statistically different between groups (mean difference 3.6, 95% CI -7.4 to 14.5). INTERPRETATION: Rates of CDMR have not increased in Ontario. Planned CDMR is associated with a decreased risk of short-term adverse outcomes compared with planned vaginal delivery. Investigation into the long-term implications of CDMR is warranted.

Assisted reproductive technology and hypertensive disorders of pregnancy: systematic review and meta-analyses.

BACKGROUND: Hypertensive disorders of pregnancy (HDP) is one of the most common pregnancy complications and causes of maternal morbidity and mortality. Assisted reproductive technology (ART) has been associated with adverse pregnancy outcomes, including HDP. However, the impact of multiple pregnancies, oocyte donation, as well as fresh and frozen embryo transfer needs to be further studied. We conducted a systematic review and meta-analyses to evaluate the association between ART and HDP or preeclampsia relative to spontaneous conception (SC). METHODS: We identified studies from EMBASE, MEDLINE, and Cochrane Library (up to April 8, 2020) and manually using structured search strategies. Cohort studies that included pregnancies after in vitro fertilization (IVF) with or without intracytoplasmic sperm fertilization (ICSI) relative to SC with HDP or preeclampsia as the outcome of interest were included. The control group was women who conceived spontaneously without ART or fertility medications. The pooled results were reported in odds ratios (OR) with 95% confidence intervals based on random effects models. Numbers needed to harm (NNH) were calculated based on absolute risk differences between exposure and control groups. RESULTS: Eighty-five studies were included after a screening of 1879 abstracts and 283 full text articles. Compared to SC, IVF/ICSI singleton pregnancies (OR 1.70; 95% CI 1.60-1.80; I2 = 80%) and multiple pregnancies (OR 1.34; 95% CI 1.20-1.50; I2 = 76%) were both associated with higher odds of HDP. Singleton pregnancies with oocyte donation had the highest odds of HDP out of all groups analyzed (OR 4.42; 95% CI 3.00-6.51; I2 = 83%). Frozen embryo transfer resulted in higher odds of HDP (OR 1.74; 95% CI 1.58-1.92; I2 = 55%) than fresh embryo transfer (OR 1.43; 95% CI 1.33-1.53; I2 = 72%). The associations between IVF/ICSI pregnancies and SC were similar for preeclampsia. Most interventions had an NNH of 40 to 100, while singleton and multiple oocyte donation pregnancies had particularly low NNH for HDP (16 and 10, respectively). CONCLUSIONS: Our meta-analysis confirmed that IVF/ICSI pregnancies are at higher odds of HDP and preeclampsia than SC, irrespective of the plurality. The odds were especially high in frozen embryo transfer and oocyte donation pregnancies.

Caesarean section in pregnancies conceived by assisted reproductive technology: a systematic review and meta-analysis.

BACKGROUND: Caesarean section rates are higher among pregnancies conceived by assisted reproductive technology (ART) compared to spontaneous conceptions (SC), implying an increase in neonatal and maternal morbidity. We aimed to compare caesarean section rates in ART pregnancies versus SC, overall, by indication (elective versus emergent), and by type of ART treatment (in-vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), fresh embryo transfer, frozen embryo transfer) in a systematic review and meta-analysis. METHODS: We searched Medline, EMBASE and CINAHL databases using the OVID Platform from 1993 to 2019, and the search was completed in January 2020. The eligibility criteria were cohort studies with singleton conceptions after in-vitro fertilization and/or intracytoplasmic sperm injection using autologous oocytes versus spontaneous conceptions. The study quality was assessed using the Newcastle Ottawa Scale and GRADE approach. Meta-analyses were performed using odds ratios (OR) with a 95% confidence interval (CI) using random effect models in RevMan 5.3, and I-squared (I2) test > 75% was considered as high heterogeneity. RESULTS: One thousand seven hundred fifty studies were identified from the search of which 34 met the inclusion criteria. Compared to spontaneous conceptions, IVF/ICSI pregnancies were associated with a 1.90-fold increase of odds of caesarean section (95% CI 1.76, 2.06). When stratified by indication, IVF/ICSI pregnancies were associated with a 1.91-fold increase of odds of elective caesarean section (95% CI 1.37, 2.67) and 1.38-fold increase of odds of emergent caesarean section (95% CI 1.09, 1.75). The heterogeneity of the studies was high and the GRADE assessment moderate to low, which can be explained by the observational design of the included studies. CONCLUSIONS: The odds of delivering by caesarean section are greater for ART singleton pregnancies compared to spontaneous conceptions. Preconception and pregnancy care plans should focus on minimizing the risks that may lead to emergency caesarean sections and finding strategies to understand and decrease the rate of elective caesarean sections.

Characteristics associated with uncomplicated pregnancies in women with obesity: a population-based cohort study.

BACKGROUND: Approximately one in five pregnant women have obesity. Obesity is associated with an increased risk of antenatal, intrapartum, and perinatal complications, but many women with obesity have uncomplicated pregnancies. At a time where maternity services are advocating for women to make informed choices, knowledge of the chance of having an uncomplicated (healthy) pregnancy is essential. The objective of this study was to calculate the rate of uncomplicated pregnancy in women with obesity and evaluate factors associated with this outcome. METHODS: This prospective cohort study was conducted using the Ontario birth registry dataset in Canada (703,115 women, April 2012-March 2017). The rate of uncomplicated or complicated composite pregnancy outcomes (hypertensive disorders of pregnancy, gestational diabetes, preterm birth, neonate small- or large- for gestational age at birth, congenital anomaly, fetal death, antepartum bleeding or preterm prelabour membrane rupture) were calculated for women with and without obesity. Associations between uncomplicated pregnancy and maternal characteristics were explored in a population of women with obesity but without other pre-existing co-morbidities (e.g., essential hypertension) or obstetric risks identified in the first trimester (e.g., multiple pregnancy), using log binomial regression analysis. RESULTS: Of the studied Ontario maternity population (body mass index not missing) 17·7% (n = 117,236) were obese. Of these 20·6% had pre-existing co-morbidities or early obstetric complicating factors. Amongst women with obesity but without early complicating factors, 58·2% (n = 54,191) experienced pregnancy without complication; this is in comparison to 72·7% of women of healthy weight and no early complicating factors. Women with obesity and no early pregnancy complicating factors are more likely to have an uncomplicated pregnancy if they are multiparous, younger, more affluent, of White or Black ethnicity, of lower weight, with normal placental-associated plasma protein-A and/or spontaneously conceived pregnancies. CONCLUSIONS: The study demonstrates that over half of women with obesity but no other pre-existing medical or early obstetric complicating factors, proceed through pregnancy without adverse obstetric complication. Care in lower-risk settings can be considered as their outcomes appear similar to those reported for low-risk nulliparous women. Further research and predictive tools are needed to inform stratification of women with obesity.

A Retrospective Cohort Study Investigating the Impact of Maternal Pre-Pregnancy Body Mass Index on Pediatric Health Service Utilization.

OBJECTIVE: Maternal weight during pregnancy impacts the health of both mother and baby. This project investigated associations between maternal pre-pregnancy body mass index (BMI) and the child's future health service utilization. METHODS: The study population comprised all women who delivered a singleton, live infant in Ontario between 2012 and 2014, and was assembled from data contained in the provincial birth registry. Health service utilization in the 24 months following birth was examined by linking data from the registry with other provincial health administrative databases housed at ICES. RESULTS: A total of 258 005 records were available for analysis. After adjusting for infant sex and maternal age, smoking status, income quintile, and pre-existing or gestational diabetes or hypertension, children born to mothers who were overweight or had obesity prior to pregnancy had increased rates of hospitalization (overweight adjusted incidence rate ratio [aIRR] 1.09, 95% confidence interval [CI] 1.06-1.12; obesity aIRR 1.20, 95% CI 1.17-1.24), physician visits (overweight aIRR 1.03, 95% CI 1.03-1.04; obesity aIRR 1.05, 95% CI 1.04-1.05) and emergency department visits (overweight aIRR 1.12, 95% CI 1.10-1.13; obesity aIRR 1.27, 95% CI 1.25-1.29) than infants born to mothers with normal pre-pregnancy BMI. CONCLUSION: Excess maternal weight was associated with greater pediatric health service utilization. Rates of health service utilization appeared to increase with maternal pre-pregnancy BMI. Future study of the reasons behind this increase may allow for early education, diagnosis, and intervention in this at-risk population.

Racial differences in contribution of prepregnancy obesity and excessive gestational weight gain to large-for-gestational-age neonates.

OBJECTIVES: To examine the racial differences in the population attributable fraction (PAF) of prepregnancy obesity and excessive gestational weight gain to large-for-gestational-age (LGA) neonates. METHODS: We conducted a population-based retrospective cohort study among all women who had prenatal screening and had a singleton live birth in a hospital (1 April 2016-31 March 2017) using data from Ontario birth registry in Canada. We used multivariable log-binomial regression models to estimate the PAF and 95% confidence interval (CI) of LGA neonates due to prepregnancy obesity and excessive gestational weight gain. All models were stratified by race (White, Asian, and Black). RESULTS: Of the 74,402 eligible women, the prevalence of prepregnancy obesity, excessive gestational weight gain, and LGA neonate was 21.1%, 60.0%, and 11.3%, respectively, for Whites; 9.3%, 45.9%, and 5.4%, respectively, for Asians; and 28.6%, 52.4%, and 7.9%, respectively, for Blacks. The association of prepregnancy obesity was greater than that of excessive gestational weight gain on LGA for all racial groups. Excessive gestational weight gain contributed more than prepregnancy obesity in Whites (PAF 32.9%, 95% CI [30.3-35.5%] and 16.6%, 95% CI [15.3-17.9%], respectively, for excessive gestational weight gain and prepregnancy obesity) and in Asians (PAF 32.1%, 95% CI [27.2-36.7%] and 11.8%, 95% CI [9.5-14.1%], respectively, for excessive gestational weight gain and prepregnancy obesity). Prepregnancy obesity (PAF 22.8%, 95% CI [17.1-28.1%]) and excessive gestational weight gain (PAF 20.1%, 95% CI [4.7-33.0%]) contributed to LGA neonates almost the same in Blacks. CONCLUSIONS: Excessive gestational weight gain contributed more to LGA neonates than prepregnancy obesity in Whites and Asians, while there was no difference between excessive gestational weight gain and prepregnancy obesity in their contributions to the LGA neonates in Blacks. The differences are mostly driven by the differential prevalence of the two risk factors across racial groups.

The determinants of maternal homocysteine in pregnancy: findings from the Ottawa and Kingston Birth Cohort.

OBJECTIVE: Observational studies have linked elevated homocysteine to vascular conditions. Folate intake has been associated with lower homocysteine concentration, although randomised controlled trials of folic acid supplementation to decrease the incidence of vascular conditions have been inconclusive. We investigated determinants of maternal homocysteine during pregnancy, particularly in a folic acid-fortified population. DESIGN: Data were from the Ottawa and Kingston Birth Cohort of 8085 participants. We used multivariable regression analyses to identify factors associated with maternal homocysteine, adjusted for gestational age at bloodwork. Continuous factors were modelled using restricted cubic splines. A subgroup analysis examined the modifying effect of MTHFR 677C>T genotype on folate, in determining homocysteine concentration. SETTING: Participants were recruited in Ottawa and Kingston, Canada, from 2002 to 2009. PARTICIPANTS: Women were recruited when presenting for prenatal care in the early second trimester. RESULTS: In 7587 participants, factors significantly associated with higher homocysteine concentration were nulliparous, smoking and chronic hypertension, while factors significantly associated with lower homocysteine concentration were non-Caucasian race, history of a placenta-mediated complication and folic acid supplementation. Maternal age and BMI demonstrated U-shaped associations. Folic acid supplementation of >1 mg/d during pregnancy did not substantially increase folate concentration. In the subgroup analysis, MTHFR 677C>T modified the effect of folate status on homocysteine concentration. CONCLUSIONS: We identified determinants of maternal homocysteine relevant to the lowering of homocysteine in the post-folic acid fortification era, characterised by folate-replete populations. A focus on periconceptional folic acid supplementation and improving health status may form an effective approach to lower homocysteine.

Neonatal outcomes in singleton pregnancies conceived by fresh or frozen embryo transfer compared to spontaneous conceptions: a systematic review and meta-analysis.

PURPOSE: The use of assisted reproductive technology (ART) has increased in the last 2 decades and continuous surveillance is needed. This systematic review aims to assess the risk of adverse neonatal outcomes (preterm birth [PTB], low birth weight [LBW], small-for-gestationalage [SGA] and large for gestational-age [LGA]), in singleton pregnancies conceived by fresh or frozen embryo transfer (FET) compared to spontaneous conceptions. METHODS: Cohort studies were identified from MEDLINE, Embase, Cochrane Library (January 2019), and manual search. Meta-analyses were performed to estimate odds ratios (OR) using random effects models in RevMan 5.3 and I-squared (I2) test > 50% was considered as high heterogeneity. RESULTS: After 3142 titles and abstracts were screened, 1180 full-text articles were assessed, and 14 were eligible. For fresh embryo transfer, the pooled ORs were PTB 1.64 (95% CI 1.46, 1.84); I2 = 97%; LBW 1.67 (95% CI 1.52, 1.85); I2 = 94%; SGA 1.46 [95% CI 1.11, 1.92]; I2 = 99%, LGA 0.88 (95% CI 0.80, 0.87); I2 = 80%). For frozen, the pooled ORs were PTB 1.39 (95% CI 1.34, 1.44); I2 = 0%; LBW 1.38 (95% CI 0.91, 2.09); I2 = 98%; SGA 0.83 (95% CI 0.57, 1.19); I2 = 0%, LGA 1.57 (95% CI 1.48, 1.68); I2 = 22%). CONCLUSIONS: When compared with spontaneous pregnancies, fresh, but not frozen was associated with LBW and SGA. Both fresh and frozen were associated with PTB. Frozen was uniquely associated with LGA. Despite improvements in ART protocols in relation to pregnancy rates, attention is needed towards monitoring adverse neonatal outcomes in these pregnancies.

Risk factors and consequences of undiagnosed cesarean scar pregnancy: a cohort study in China.

BACKGROUND: The historically high cesarean section rate and the recent change in second-child policy could increase the risk of cesarean scar pregnancy (CSP) in China. This study aims to assess risk factors and consequences of undiagnosed CSP in China. METHODS: We conducted a retrospective cohort study between January 2013 and December 2017 in Qingyuan, Guangdong, China. Independent risk factors for undiagnosed CSP at the first contact with healthcare providers were assessed by log binomial regression analysis. Occurrence of serious complications was compared between undiagnosed and diagnosed CSP cases. RESULTS: A total of 195 women with CSP were included in the analysis. Of them, 81 (41.5%) women were undiagnosed at the first contact with healthcare providers. Women initially cared in primary or secondary hospitals were at increased risk for undiagnosed CSP: adjusted relative risks (95% confidence intervals) were 3.28 (2.06, 5.22) and 1.91 (1.16, 3.13), respectively, compared with women initially cared in the tertiary hospital. Undiagnosed CSP cases had higher incidences in serious complications (11 versus 0) and post-surgery anemia (23 (28.4%) versus 8 (7.0%)), stayed longer in hospital, and cost higher than diagnosed CSP cases. CONCLUSIONS: Initial care provided at primary or secondary maternity care facilities is an important risk factor for undiagnosed CSP, with serious consequences to the affected women.

The role of maternal homocysteine concentration in placenta-mediated complications: findings from the Ottawa and Kingston birth cohort.

BACKGROUND: Homocysteine is an intermediate metabolite implicated in the risk of placenta-mediated complications, including preeclampsia, placental abruption, fetal growth restriction, and pregnancy loss. Large cohort and case-control studies have reported inconsistent associations between homocysteine and these complications. The purpose of this study was to investigate whether elevated maternal plasma homocysteine concentration in the early to mid-second trimester is associated with an increased risk of placenta-mediated complications. We examined the following potential moderating factors that may explain discrepancies among previous studies: high-risk pregnancy and the MTHFR 677C>T polymorphism. METHODS: We analyzed data from participants recruited to the Ottawa and Kingston (OaK) Birth Cohort from 2002 to 2009 in Ottawa and Kingston, Canada. The primary outcome was a composite of any placenta-mediated complication, defined as a composite of small for gestational age (SGA) infant, preeclampsia, placental abruption, and pregnancy loss. Secondary outcomes were, individually: SGA infant, preeclampsia, placental abruption, and pregnancy loss. We conducted multivariable logistic regression analyses with homocysteine as the primary continuous exposure, adjusting for gestational age at the time of bloodwork and explanatory maternal characteristics. The functional form, i.e., the shape of the homocysteine association with the outcome was examined using restricted cubic splines and information criteria (Akaike's/Bayesian Information Criterion statistics). Missing data were handled with multiple imputation. RESULTS: 7587 cohort participants were included in the study. Maternal plasma homocysteine concentration was significantly associated (linearly) with an increased risk of both the composite outcome of any placenta-mediated complication (p = 0.0007), SGA (p = 0.0010), severe SGA, and marginally with severe preeclampsia, but not preeclampsia, placental abruption and pregnancy loss. An increase in homocysteine concentration significantly increased the odds of any placenta-mediated complication (odds ratio (OR) for a 5 µmol/L increase: 1.63, 95% Confidence Interval (CI) 1.23-2.16) and SGA (OR 1.76, 95% CI 1.25-2.46). Subgroup analyses indicated some potential for modifying effects of the MTHFR 677C>T genotype and high-risk pregnancy, although the interaction was not statistically significant (high-risk subgroup OR 2.37, 95% CI 1.24-4.53, p-value for interaction =0.14). CONCLUSIONS: Our results suggest an independent effect of early to mid-pregnancy elevated maternal homocysteine on placenta-mediated pregnancy complications.

Guideline No. 391-Pregnancy and Maternal Obesity Part 1: Pre-conception and Prenatal Care.

OBJECTIVE: This guideline will review key aspects in the pregnancy care of women with obesity. Part I will focus on pre-conception and pregnancy care. Part II will focus on team planning for delivery and Postpartum Care. INTENDED USERS: All health care providers (obstetricians, family doctors, midwives, nurses, anaesthesiologists) who provide pregnancy-related care to women with obesity. TARGET POPULATION: Women with obesity who are pregnant or planning pregnancies. EVIDENCE: Literature was retrieved through searches of Statistics Canada, Medline, and The Cochrane Library on the impact of obesity in pregnancy on antepartum and intrapartum care, maternal morbidity and mortality, obstetrical anaesthesia, and perinatal morbidity and mortality. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2018. Grey (unpublished) literature was identified through searching the websites of health technology assessment and related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. VALIDATION METHODS: The content and recommendations were drafted and agreed upon by the authors. Then the Maternal-Fetal Medicine Committee peer reviewed the content and submitted comments for consideration, and the Board of the Society of Obstetricians and Gynaecologists of Canada (SOGC) approved the final draft for publication. Areas of disagreement were discussed during meetings, at which time consensus was reached. The level of evidence and quality of the recommendation made were described using the Evaluation of Evidence criteria of the Canadian Task Force on Preventive Health Care. BENEFITS, HARMS, AND COSTS: Implementation of the recommendations in these guidelines may increase obstetrical provider recognition of the issues affected pregnant individuals with obesity, including clinical prevention strategies, communication between the health care team, the patient and family as well as equipment and human resource planning. It is hoped that regional, provincial and federal agencies will assist in the education and support of coordinated care for pregnant individuals with obesity. GUIDELINE UPDATE: SOGC guidelines will be automatically reviewed 5 years after publication. However, authors can propose another review date if they feel that 5 years is too short/long based on their expert knowledge of the subject matter. SPONSORS: This guideline was developed with resources funded by the SOGC. SUMMARY STATEMENTS: RECOMMENDATIONS.

Guideline No. 392-Pregnancy and Maternal Obesity Part 2: Team Planning for Delivery and Postpartum Care.

OBJECTIVE: This guideline will review key aspects in the pregnancy care of women with obesity. Part I will focus on Preconception and Pregnancy Care. Part II will focus on Team Planning for Delivery and Postpartum Care. INTENDED USERS: All health care providers (obstetricians, family doctors, midwives, nurses, anaesthesiologists) who provide pregnancy-related care to women with obesity. TARGET POPULATION: Women with obesity who are pregnant or planning pregnancies. EVIDENCE: Literature was retrieved through searches of Statistics Canada, Medline, and The Cochrane Library on the impact of obesity in pregnancy on antepartum and intrapartum care, maternal morbidity and mortality, obstetric anaesthesia, and perinatal morbidity and mortality. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2018. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. VALIDATION METHODS: The content and recommendations were drafted and agreed upon by the authors. Then the Maternal-Fetal Medicine Committees peer reviewed the content and submitted comments for consideration, and the Board of the Society of Obstetricians and Gynaecologists of Canada (SOGC) approved the final draft for publication. Areas of disagreement were discussed during meetings at which time consensus was reached. The level of evidence and quality of the recommendation made were described using the Evaluation of Evidence criteria of the Canadian Task Force on Preventive Health Care. BENEFITS, HARMS, AND COSTS: Implementation of the recommendations in these guidelines may increase obstetrical provider recognition of the issues affecting pregnant individuals with obesity, including clinical prevention strategies, communication between the health care team, the patient and family as well as equipment and human resource planning. It is hoped that regional, provincial and federal agencies will assist in the education and support of coordinated care for pregnant individuals with obesity. GUIDELINE UPDATE: SOGC guideline will be automatically reviewed 5 years after publication. However, authors can propose another review date if they feel that 5 years is too short/long based on their expert knowledge of the subject matter. SPONSORS: This guideline was developed with resources funded by the SOGC. SUMMARY STATEMENTS: RECOMMENDATIONS.

Directive clinique No 392 - Grossesse et obésité maternelle Partie 2 : Planification en équipe de l'accouchement et soins post-partum.

OBJECTIF: La présente directive clinique aborde les aspects essentiels des soins prénataux chez les femmes atteintes d'obésité. La partie 1 porte sur la préconception et les soins prénataux. La partie 2 porte sur la planification en équipe de l'accouchement et les soins post-partum. UTILISATEURS CONCERNéS: Tous les fournisseurs de soins de santé (obstétriciens, médecins de famille, sages-femmes, infirmières, anesthésiologistes) qui prodiguent des soins relatifs à la grossesse auprès de femmes atteintes d'obésité. POPULATION CIBLE: Femmes atteintes d'obésité qui sont enceintes ou prévoient le devenir. DONNéES PROBANTES: Des recherches ont été menées en consultant les ressources de Statistique Canada, de Medline et de Cochrane Library en vue d'en tirer la littérature relativement aux effets de l'obésité durant la grossesse sur les soins prénataux et intrapartum, la morbidité et la mortalité maternelles, l'anesthésie obstétricale ainsi que sur la morbidité et la mortalité périnatales. Seuls les résultats de revues systématiques, d'essais cliniques randomisés ou comparatifs et d'études observationnelles ont été retenus. Aucune restriction de date ou de langue n'a été employée. Les recherches ont été mises à jour régulièrement, et les résultats ont été incorporés à la directive clinique jusqu'en septembre 2018. Nous avons également tenu compte de la littérature grise (non publiée) obtenue sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes pertinents, dans des collections de directives cliniques et des registres d'essais cliniques, et auprès d'associations nationales et internationales de médecins spécialistes. MéTHODES DE VALIDATION: Le contenu et les recommandations ont été rédigés et acceptés par les auteurs. Les membres du comité de médecine fœto-maternelle ont ensuite passé en revue le contenu et formulé des commentaires aux fins d'examen. Enfin, le conseil d'administration de la Société des obstétriciens et gynécologues du Canada (SOGC) a approuvé la publication de la version définitive de la directive. Les points de désaccord ont été abordés lors de réunions pour enfin arriver à un consensus. La qualité des données et des recommandations a été déterminée à l'aide des critères d'évaluation décrits par le Groupe d'étude canadien sur les soins de santé préventifs. AVANTAGES, PRéJUDICE ET COûTS: La mise en place des recommandations des présentes directives peut améliorer la reconnaissance des fournisseurs de soins obstétricaux relativement aux problèmes qui touchent les personnes enceintes atteintes d'obésité, notamment au moyen de stratégies de prévention clinique; de la communication entre l'équipe de soins de santé, la patiente et la famille; et de la planification de l'équipement et des ressources humaines. Il est à espérer que les organismes régionaux, provinciaux et fédéraux participeront à la formation et au soutien en matière de soins coordonnés pour les personnes enceintes atteintes d'obésité. MISE à JOUR DE LA DIRECTIVE CLINIQUE: Les directives de la SOGC sont automatiquement passées en revue 5 ans après leur publication. Les auteurs peuvent toutefois proposer une autre date de réévaluation s'ils croient qu'une période de 5 ans est trop courte ou trop longue en fonction de leurs connaissances du sujet à titre d'experts en la matière. PROMOTEURS: La présente directive a été élaborée à l'aide de ressources financées par la SOGC. DéCLARATIONS SOMMAIRES: RECOMMANDATIONS.