Grandmaternal pre-pregnancy body mass index and infant birthweight: a mediation analysis of maternal pre-pregnancy body mass index.

The objectives of this study were to examine the total effect of grandmaternal [G0] pre-pregnancy body mass index (BMI) on infant [G2] birthweight z-score and to quantify the mediation role of maternal [G1] pre-pregnancy BMI. Data were extracted from the Nova Scotia 3G Multigenerational Cohort. The association between G0 pre-pregnancy BMI and G2 birthweight z-score and the mediated effect by G1 pre-pregnancy BMI were estimated using g-computation with adjustment for confounders identified using a directed acyclic graph and accounting for intermediate confounding. 20822 G1-G2 dyads from 18450 G0 were included. Relative to G0 normal weight, G0 underweight decreased mean G2 birthweight z-score (-0.11, 95% confidence interval (CI) -0.20, -0.030), while G0 overweight and obesity increased mean G2 birthweight z-score (0.091 [95% CI 0.034, 0.15] and 0.22 [95% CI 0.11, 0.33]). G1 pre-pregnancy BMI partly mediated the association, with the largest effect size observed for G0 obesity (0.11, 95% CI 0.080, 0.14). Estimates of the direct effect were close to the null. In conclusion, grandmaternal pre-pregnancy BMI was associated with infant birthweight z-score. Maternal pre-pregnancy BMI partly mediated the association, suggesting that factors related to BMI may play an important role in the transmission of weight across the maternal line.

A Postpartum Perineal Clinic in Nova Scotia: Characteristics Associated With Attendance and Its Association With Recurrent Obstetrical Anal Sphincter Tears.

OBJECTIVES: The Healthy Recovery after Childbirth Clinic (HRCC) in Nova Scotia provides postpartum care to patients who experience obstetric anal sphincter injuries (OASIS). The purpose of this study was to describe characteristics associated with HRCC attendance, characteristics associated with a trial of labour in a subsequent delivery, and OASIS recurrence by HRCC attendance status. METHODS: A retrospective cohort study using the Atlee Perinatal Database and clinical record review included primiparous individuals who sustained an OASIS at IWK Health in Halifax between 2013 and 2020. The χ2 and Fisher exact tests were performed to compare groups. RESULTS: Of the 1041 individuals included, 67% attended HRCC. Attendance increased from 58% in 2013-2015 to 77% in 2019-2020. Younger age (<25 years) and smoking were associated with lower HRCC attendance (P = 0.07 and <0.01, respectively). Other characteristics, including area-level income and driving distance to HRCC, were not associated with attendance (P > 0.05). Of the 439 individuals who had a subsequent delivery, 92% had a trial of labour. Individuals with fourth-degree injury were less likely to attempt a trial of labour than those with third-degree injury (73% vs. 94%, P < 0.01). Of those who delivered vaginally, OASIS recurrence was similar in those who did and did not attend the HRCC (7.5% vs. 6.5%, P = 0.84). CONCLUSIONS: HRCC attendance was high, but the disparity by age and smoking status suggests some barriers to access that should be explored. Although we found no difference in OASIS recurrence by HRCC attendance, more research with larger samples with adjustment for confounders is needed.

Health Care Utilization in the First 7 Years in Children with Fetal Growth Abnormalities: A Retrospective Cohort Study.

OBJECTIVE: To investigate the relationship between birth weight for gestational age and health care utilization of term offspring from birth to 7 years. STUDY DESIGN: We used a population-based retrospective cohort study of infants (≥37 weeks' gestational age) born between 2003 and 2007 in the Canadian province of Nova Scotia (n = 42 050). Perinatal records were linked to provincial administrative health data from birth to age 7 years. The primary outcome was health care utilization (physician visits and hospital admissions) and costs. Birth weight was categorized as small for gestational age (SGA, <10th percentile), appropriate for gestational age (AGA), or large for gestational age (LGA, >90th percentile). Regression models adjusted for potential confounders were used to investigate the associations. RESULTS: Children born SGA had a higher number of specialist visits and hospital admissions, a longer length of stay for the birth admission, and, as a result, higher physician and hospital costs amounting to a cost differential of Can $1222 during the first 7 years of life compared with children born AGA. By contrast, health care use and costs did not differ between children born LGA and AGA. CONCLUSION: Former SGA term infants have a moderate increase in health care use and costs in early childhood compared with former AGA infants, and LGA birth at term is not associated with higher health care utilization.

Association between second stage of labour length and risk of obstetrical anal sphincter injury in nulliparous women: a population-based retrospective cohort study.

INTRODUCTION AND HYPOTHESIS: Obstetrical anal sphincter injury (OASIS) is a common consequence of vaginal delivery in nulliparas and carries the risk of short- and long-term morbidity. The objective of this study was to estimate the association between the duration of the second stage of labour and OASIS risk. METHODS: A population-based, retrospective cohort of nulliparas delivering singleton, vertex, non-anomalous fetuses at term in Nova Scotia, Canada, from 2005 to 2019, were identified using the Nova Scotia Atlee Perinatal Database. Poisson regression models were used to estimate risk ratios (RR) with robust 95% confidence intervals (CI) adjusting for confounding variables to investigate the association between the length of the second stage and OASIS in the entire cohort and in operative vaginal deliveries. RESULTS: Of 36,662 participants, 7.6% sustained an OASIS (6.8% third-degree, 0.8% fourth-degree tear). The proportion of participants who sustained an OASIS increased over the study period. For each 30-min increase in the length of second stage, the OASIS risk increased by 11% (RR 1.11, 95% CI 1.10-1.12). When stratified by mode of delivery, second stage length ≥ 90 min was associated with an increased OASIS risk in spontaneous (RR 1.35, 95% CI 1.15-1.58) and vacuum-assisted vaginal deliveries (RR 1.42, 95% CI 1.11-1.81). In forceps-assisted vaginal deliveries, OASIS risk was increased, with shorter and longer durations of the second stage. CONCLUSION: Increasing length of the second stage of labour was associated with increasing risk of OASIS overall, but the association was heterogeneous between modes of delivery. Length of the second stage should be considered in counseling about OASIS risk.

The Relationship Between Pre-Pregnancy Attempts to Lose Weight and Gestational Weight Gain: An Exploratory Primary Care Prospective Cohort Study.

OBJECTIVE: The primary objective of this study was to explore the association between weight cycling in the 6 months prior to pregnancy and gestational weight gain concordance with the 2009 Institute of Medicine guidelines for weight gain in pregnancy. METHODS: This was a prospective cohort study. Participants were women aged 18 years or older with a singleton pregnancy who had a prenatal appointment between April 1 and August 31, 2019. Eligible women completed a questionnaire that assessed their pre-pregnancy attempts to lose weight, measured with a modified version of the Weight Cycling subscale within the Revised Restraint Scale. After delivery, participants' last recorded gestational weight before delivery, and corresponding gestational ages were obtained from prenatal records. RESULTS: One hundred and ninety-five pregnant women consented to participate in the study (a 95.6% response rate). Of them, 5 were excluded; therefore, 190 participants were included in the analysis. One-third of participants had attempted to lose weight in the 6 months before pregnancy. Logistic regression showed that for every one-unit increase in Weight Cycling score, the odds of excess gestational weight gain increased by a factor of 1.32. CONCLUSION: Women's pre-conceptual efforts to enter pregnancy at a lower BMI should be approached in a manner that avoids pre-pregnancy weight cycling.

The 3G Multigenerational Cohort of Nova Scotian women and their mothers and offspring.

BACKGROUND: The negative impact of exposures such as maternal obesity, excessive gestational weight gain, and hypertension in pregnancy on the health of the next generation has been well studied. Evidence from animal studies suggests that the effects of in utero exposures may persist into the second generation, but the epidemiological literature on the influence of pregnancy-related exposures across three generations in humans is sparse. OBJECTIVES: This cohort was established to investigate associations between antenatal and perinatal exposures and health outcomes in women and their offspring. POPULATION: The cohort includes women who were born and subsequently had their own pregnancies in the Canadian province of Nova Scotia from 1980 onward. DESIGN: Intergenerational linkage of data in the Nova Scotia Atlee Perinatal Database was used to establish a population-based dynamic retrospective cohort. METHODS: The cohort has prospectively collected information on sociodemographics, maternal health and health behaviours, pregnancy health and complications, and obstetrical and neonatal outcomes for two generations of women and their offspring. PRELIMINARY RESULTS: As of October 2018, the 3G cohort included 14 978 grandmothers (born 1939-1986), 16 766 mothers or cohort women (born 1981-2003), and 28 638 children (born 1996-2018). The cohort women were generally younger than Nova Scotian women born after 1980, and as a result, characteristics associated with pregnancy at a younger age were more frequently seen in the cohort women; sampling weights will be created to account for this design effect. The cohort will be updated annually to capture future deliveries to women who are already in the cohort and women who become eligible for inclusion when they deliver their first child. CONCLUSIONS: The 3G Multigenerational Cohort is a population-based cohort of women and their mothers and offspring, spanning a time period of 38 years, and provides the opportunity to study inter- and transgenerational associations across the maternal line.

Optimal Timing of Prenatal Ultrasound in Predicting Birth Weight in Diabetic Pregnancies.

OBJECTIVE: This study sought to determine the optimal timing of ultrasound in the third trimester to predict birth weight accurately in diabetic women with a singleton pregnancy. METHODS: A retrospective cohort study of all diabetic women with a singleton pregnancy treated in Halifax, Nova Scotia, was performed. Estimated fetal weight was derived from ultrasound measures using the Hadlock2 equation. The Mongelli equation was used to predict birth weight. The association between gestational age at ultrasound and accuracy of predicted birth weight was assessed, with accuracy as a continuous variable representing the difference between predicted and actual birth weight and as a categorical variable (with four gestational age categories) representing whether predicted birth weight was within, over, or under 250 g of actual birth weight RESULTS: The cohort of 943 women comprised 121 (12.8%) with type 1 diabetes, 111 (11.7%) with type 2 diabetes, and 711 (75.4%) with gestational diabetes. Ultrasound scans performed at term were the most accurate in predicting birth weight. At this gestational age, the mean difference between predicted and actual birth weight was -30 g (95% confidence interval -109 to -48). After adjusting for maternal body mass index, age, smoking, type of diabetes, and interval between ultrasound examination and delivery, accuracy improved as gestational age at ultrasound increased (P = 0.005). The odds of underpredicting or overpredicting birth weight were not significantly affected by the timing of the ultrasound examination. CONCLUSION: Because the predictive accuracy of ultrasound prediction of birth weight improves with gestational age, fetal growth assessment at term is recommended to aid with delivery planning in women with diabetes.

Incidence, Intrapartum Risk Factors, and Prognosis of Neonatal Hypoxic-Ischemic Encephalopathy Among Infants Born at 35 Weeks Gestation or More.

INTRODUCTION: Neonatal hypoxic-ischemic encephalopathy (HIE) is associated with neonatal mortality, acute neurological injury, and long-term neurodevelopmental disabilities; however, the association between intrapartum factors and HIE remains unclear. METHODS: This population-based cohort study used linked obstetrical and newborn data derived from the Nova Scotia Atlee Perinatal Database (NSAPD, 1988-2015) and the AC Allen Perinatal Follow-Up Program Database (2006-2015) for all pregnancies with live, non-anomalous newborns ≥35 weeks gestation, not delivered by pre-labour cesarean section. Temporal trends in HIE incidence were described, and logistic regression estimated odds ratios (OR) with 95% confidence intervals (CI) for the association of intrapartum factors with HIE. RESULTS: The NSAPD identified 227 HIE cases in the population of 226 711 deliveries from 1988 to 2015. Women with clinical chorioamnionitis in labour (OR 8.0; 95% CI 3.9-16), emergency cesarean delivery (OR 10; 95% CI 7.6-14), shoulder dystocia (OR 3.5; 95% CI 2.1-5.7), placental abruption (OR 18; 95% CI 11-29), and cord prolapse (OR 30; 95% CI 15-61) were more likely to have newborns with HIE. Two-thirds of newborns with HIE had an abnormal intrapartum fetal heart rate tracing. The mortality rate among infants with HIE was 27% by 3 years of age. Neurodevelopmental outcomes in the surviving infants were normal in 43% and showed severe developmental delay in 40%. CONCLUSION: Overall, the rate of HIE was low in infants born at ≥35 weeks gestation. The identification of associated intrapartum factors should promote increased surveillance in these clinical situations and emphasize the importance of careful management to optimize newborn outcomes.

Maternal pre-pregnancy obesity and health care utilization and costs in the offspring.

BACKGROUND/OBJECTIVE: The association between maternal pre-pregnancy obesity and adverse child health outcomes is well described, but there are few data on the relationship with offspring health service use. We examined the influence of maternal pre-pregnancy obesity on offspring health care utilization and costs over the first 18 years of life. METHODS: This was a population-based retrospective cohort study of children (n = 35,090) born between 1989 and 1993 and their mothers, who were identified using the Nova Scotia Atlee Perinatal Database and linked to provincial administrative health data from birth through 2014. The primary outcome was health care utilization as determined by the number and cost of physician visits, hospital admissions and days, and high utilizer status (>95th percentile of physician visits). The secondary outcome was health care utilization by ICD chapter. Maternal pre-pregnancy weight was categorized as normal weight, overweight, or obese. Multivariable-adjusted regression models were used to examine the association between maternal weight status and offspring health care use. RESULTS: Children of mothers with pre-pregnancy obesity had more physician visits (10%), hospital admissions (16%), and hospital days (10%) than children from mothers of normal weight over the first 18 years of life. Offspring of mothers with obesity had C$356 higher physician costs and C$1415 hospital costs over 18 years than offspring of normal weight mothers. Children of mothers with obesity were 1.74 times more likely to be a high utilizer of health care and had higher rates of physician visits and hospital stays for nervous system and sense organ disorders, respiratory disorders, and gastrointestinal disorders compared to children of normal weight mothers. CONCLUSION: Our findings suggest that maternal pre-pregnancy overweight and obesity are associated with slightly higher offspring health care utilization and costs in the first 18 years of life.

Cesarean Delivery and Healthcare Utilization and Costs in the Offspring: A Retrospective Cohort Study.

OBJECTIVE: To examine the association between cesarean delivery and healthcare utilization and costs in offspring from birth until age 7 years. STUDY DESIGN: A retrospective cohort study of singleton term births in the Canadian province of Nova Scotia between 2003 and 2007 followed until age 7 years was conducted using data from the Nova Scotia Atlee Perinatal Database and administrative health data. The main exposure was mode of delivery (cesarean delivery vs vaginal birth); the outcome was healthcare utilization and costs during the first 7 years of life. Associations were modeled using multiple regression adjusting for maternal prepregnancy weight and sociodemographic factors. RESULTS: In total, 32 464 births were included in the analysis. Compared with children born by vaginal birth, children born by cesarean delivery had more physician visits (incidence rate ratio 1.06, 95% CI 1.05-1.08) and longer hospital stays (incidence rate ratio 1.12, 95% CI 1.03-1.21) and were more likely to be high utilizers of physician visits (OR 1.23, 95% CI 1.10-1.37). Physician and hospital costs were $775 higher for children born by cesarean delivery compared with vaginal birth. CONCLUSIONS: Cesarean delivery compared with vaginal birth is associated with small but statistically significant increases in healthcare utilization and costs during the first 7 years of life.

Barriers Preventing Medical Students From Performing Pelvic Examinations During Obstetrics and Gynaecology Clinical Clerkship Rotations.

OBJECTIVE: This study sought to identify barriers that prevent medical students from performing pelvic examinations in their obstetrics and gynaecology (Ob/Gyn) clinical clerkship rotations and to compare the perspectives of faculty, residents, nurses, and students regarding perceived barriers. METHODS: An electronic survey was distributed to third-year Dalhousie University (Halifax, NS) medical students on completion of their Ob/Gyn clerkship rotations in the 2015-2016 academic year and to Ob/Gyn nursing staff, faculty, and residents (Canadian Task Force Classification III). RESULTS: There were 82 responses, giving an overall response rate of 28%. Students reported performing an average of 9.2 speculum examinations, 3.8 cervical checks, and 2.8 bimanual examinations during their 6-week rotations. They reported being declined the opportunity to perform an examination an average of 7.1 times. Students perceived themselves to be more competent performing these examinations compared with staff perception of student competency. Students perceived resident interest in teaching, resident and staff time constraints, and patient willingness to have a medical student involved in their examination as frequent barriers. Faculty, residents, and nurses perceived student gender, patient willingness, difficulty of examination, and resident time constraints to be significant barriers. CONCLUSION: This study is the first to examine multidisciplinary perspectives on perceived barriers to medical students performing pelvic examinations. Staff and students have different perceptions of a student's competence performing these examinations. Existing barriers are likely multifactorial.

Characteristics and Outcomes of Adolescent Births in Nova Scotia: A Retrospective Cohort Study.

OBJECTIVE: This study sought to examine the maternal characteristics and outcomes of adolescent births in Nova Scotia. METHODS: The investigators conducted a retrospective population-based cohort study using the Nova Scotia Atlee Perinatal Database. Maternal characteristics and maternal and neonatal outcomes of singleton live births between 2006 and 2015 were compared between adolescent (aged 12 to 19) and adult (aged 20 to 35) women. Associations were examined using log-binomial regression models. RESULTS: Of the 35 111 births that occurred during the study period, 11% were to adolescent mothers. Compared with adult women, adolescents had higher rates of smoking and substance abuse and were of lower socioeconomic status. Adolescent mothers were more than twice as likely as women aged 20 to 35 to smoke during pregnancy. Adolescent women were significantly less likely to have gestational diabetes, need induction of labour, have an assisted vaginal delivery, require a Caesarean section, have a large-for-gestational age infant, or breastfeed at discharge compared with the 20 to 35 age group. Birth of a small-for-gestational age infant and other adverse neonatal outcomes were more frequently seen in adolescents compared with adult women in the unadjusted models, but this difference vanished in models adjusted for sociodemographic factors and smoking. CONCLUSION: This study highlights disparities in socioeconomic characteristics and health behaviours between births in adolescent and adult mothers and suggests that a targeted multidisciplinary approach would be valuable for the pregnant adolescent. The role of antenatal support for pregnant adolescents is reinforced because sociodemographic factors and smoking accounted for differences in neonatal outcomes relative to adult women.

Factors Associated with Trial of Labour and Mode of Delivery in Robson Group 5: A Select Group of Women With Previous Caesarean Section.

OBJECTIVE: To determine the proportion of women in Robson group 5 (RG5) who were eligible for a trial of labour after Caesarean (TOLAC) and, among eligible candidates, identify determinants of having a TOLAC and subsequent vaginal delivery (VD). METHODS: This population-based cohort study used data derived from the Nova Scotia Atlee Perinatal Database. Deliveries from 1998-2014 to women in RG5 (≥1 previous CS with a singleton term cephalic fetus) were included. Eligibility for a TOLAC was based on SOGC criteria. Multivariable logistic regression was used to identify characteristics independently associated with TOLAC and VD. The characteristics associated with VD were used in a logistic model to predict the theoretical probability of VD in women who did not have a TOLAC. RESULTS: Of the 15 111 deliveries in RG5, 75.3% were by CS. Of the 14 763 eligible women, 5488 (37.2%) had a TOLAC, of which 3739 (68.1%) resulted in VD. Predictors of VD included high area-level income and either a CS without labour or a spontaneous VD in the preceding pregnancy. While mode of previous delivery also predicted TOLAC among eligible women, high area-level income was associated with reduced odds of TOLAC. The probability of VD in women who did not undergo TOLAC was estimated to be 47.1%, and the lowest CS rate attainable in RG5 was estimated at 46.3%. CONCLUSIONS: Sociodemographic factors such as income and previous mode of delivery were associated with the rates of TOLAC and subsequent VD in eligible women, and suggest that the Caesarean section rate in RG5 could be safely reduced.

Examining the provisional guidelines for weight gain in twin pregnancies: a retrospective cohort study.

BACKGROUND: Weight gain during pregnancy has an important impact on maternal and neonatal health. Unlike the Institute of Medicine (IOM) recommendations for weight gain in singleton pregnancies, those for twin gestations are termed "provisional", as they are based on limited data. The objectives of this study were to determine the neonatal and maternal outcomes associated with gaining weight below, within and above the IOM provisional guidelines on gestational weight gain in twin pregnancies, and additionally, to explore ranges of gestational weight gain among women who delivered twins at the recommended gestational age and birth weight, and those who did not. METHODS: A retrospective cohort study of women who gave birth to twins at ≥20 weeks gestation, with a birth weight ≥ 500 g was conducted in Nova Scotia, Canada (2003-2014). Our primary outcome of interest was small for gestational age (<10th percentile). In order to account for gestational age at delivery, weekly rates of 2nd and 3rd trimester weight gain were used to categorize women as gaining below, within, or above guidelines. We performed traditional regression analyses for maternal outcomes, and to account for the correlated nature of the neonatal outcomes in twins, we used generalized estimating equations (GEE). RESULTS: A total of 1482 twins and 741 mothers were included, of whom 27%, 43%, and 30% gained below, within, and above guidelines, respectively. The incidence of small for gestational age in these three groups was 30%, 21%, and 20%, respectively, and relative to gaining within guidelines, the adjusted odds ratios were 1.44 (95% CI 1.01-2.06) for gaining below and 0.92 (95% CI 0.62-1.36) for gaining above. The gestational weight gain in women who delivered twins at 37-42 weeks with average birth weight ≥ 2500 g and those who delivered twins outside of the recommend ranges were comparable to each other and the IOM recommendations. CONCLUSIONS: While gestational weight gain below guidelines for twins was associated with some adverse neonatal outcomes, additional research exploring alternate ranges of gestational weight gain in twin pregnancies is warranted, in order to optimize neonatal and maternal outcomes.

Predicting the Risk of Macrosomia at Mid-Pregnancy Among Non-Diabetics: A Retrospective Cohort Study.

OBJECTIVE: To identify factors known in mid-pregnancy to be associated with risk of macrosomia (≥4000 g) among non-diabetic women and to develop a risk score to allow early identification of women at high risk. METHODS: Data were obtained from a population-based perinatal database and a hospital laboratory database in Nova Scotia, Canada. The study included singleton live births born to non-diabetic women between 1998 and 2005. Logistic regression was used to identify risk factors significantly associated with macrosomia. Risk scoring systems were developed for nulliparous and parous women separately and validated using the C-statistic. RESULTS: Of the 23 857 mother-infant pairs included in the study, 16.7% of the infants were macrosomic. In nulliparous women, seven risk factors were identified, of which pre-pregnancy weight ≥90 kg with an OR of 4.8 (95% CI: 3.9 to 6.0) contributed a greater number of points to the risk score. The resulting risk score corresponded to a range of estimated risk of 0.2% to 47.0% and had a C-statistic of 0.70. In parous women, the most points were assigned to women with a previous large birth (OR: 3.7; 95% CI: 3.2-4.0) and a pre-pregnancy weight ≥90 kg (OR: 3.8; 95% CI: 3.1-4.7). The resulting risk score corresponded to a range of estimated risk of 0.4% to 88.0% and had a C-statistic of 0.75. CONCLUSIONS: Macrosomia risk can be estimated by a simple calculation based on a woman's risk factor profile at mid-pregnancy.

Vitamin D Status and Gestational Diabetes: Effect of Smoking Status during Pregnancy.

BACKGROUND: Vitamin D status, as measured by serum 25-hydroxyvitamin D (25(OH)D), has been shown in some studies to be inversely associated with gestational diabetes risk. Recently, it has been suggested that maternal smoking status may modify this relationship. We explored the association between 25(OH)D concentration and gestational diabetes and determined if there was an interaction between smoking and 25(OH)D. METHODS: A nested case-control study was conducted in Halifax, Nova Scotia and Quebec City, Quebec. Women were recruited before 20 weeks gestation and 25(OH)D was measured. Cases were women who developed gestational diabetes and controls were frequency matched to cases on study site, gestational age at blood draw, and season and year of blood draw. Logistic regression models estimated adjusted odds ratios (aOR) and 95% confidence intervals (CI). Models were tested for multiplicative and additive interaction, which was estimated by relative excess risk due to interaction (RERI). RESULTS: The study included 395 gestational diabetes cases and 1925 controls. Women who smoked during pregnancy and had 25(OH)D concentrations <30 nmol/L had an aOR = 3.73 [95% CI 1.95, 7.14] compared to non-smokers with 25(OH)D concentrations ≥50 nmol/L. Additive interaction was detected between smoking status and 25(OH)D [RERI = 2.44, 95% CI 0.03, 4.85]. CONCLUSION: Our study supports the inverse association of vitamin D status with gestational diabetes risk, particularly among women who smoke during pregnancy. More research is needed to confirm this finding and, if confirmed, to determine the mechanism by which the combined effect of smoking and low vitamin D status increases the risk of developing gestational diabetes.

Gestational Weight Gain and Perinatal Outcomes in Adolescent Mothers: A Retrospective Cohort Study.

OBJECTIVE: Optimal gestational weight gain (GWG) may differ for adolescents since they themselves may continue to grow throughout pregnancy. We examined the associations between GWG and perinatal outcomes among adolescents aged < 20 years and determined whether they differed from the associations among adult women aged 20 to 35 years. METHODS: We conducted a retrospective cohort study of live born, singleton deliveries to 3725 adolescents and 50 400 adult women in Nova Scotia between 2003 and 2014. GWG was categorized as below, within, or above the 2009 Institute of Medicine recommendations. Primary outcomes were preterm birth (< 37 weeks), small for gestational age (SGA; < 10(th) percentile), large for gestational age (LGA; > 90th percentile), and delivery by Caesarean section. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were estimated from logistic regression models. RESULTS: Adolescent mothers with GWG above the recommendations (relative to mothers who gained within the recommendations) had higher odds of having an LGA neonate (OR 2.20; 95% CI 1.62 to 2.99) and having a Caesarean section (OR 1.33; 95% CI 1.07 to 1.64), but lower odds of having an SGA neonate (OR 0.65; 95% CI 0.51 to 0.84). Adolescent mothers with low GWG had decreased odds of having an LGA neonate (OR 0.58; 95% CI 0.34 to 0.98) and increased odds of having an SGA neonate (OR 1.72; 95% CI 1.30 to 2.27). CONCLUSION: Among adolescents, GWG was significantly associated with several perinatal outcomes. More research considering other outcomes is needed to determine the optimal GWG for adolescent women.

Cord blood vitamin D status and neonatal outcomes in a birth cohort in Quebec, Canada.

PURPOSE: Some evidence suggests that low maternal vitamin D status adversely affects perinatal health but few studies have examined cord blood vitamin D status. This project aimed to determine the association between the cord blood concentration of 25-hydroxyvitamin D [25(OH)D] and neonatal outcomes. METHODS: A nested case-control study was conducted in Quebec City, Canada from 2005 to 2010. Included were 83 cases of low birthweight (LBW; <2500 g), 301 cases of small for gestational age (SGA; <10th percentile), 223 cases of preterm birth (PTB; <37 weeks' gestation), and 1027 controls. Levels of 25(OH)D were determined by chemiluminescence immunoassay. Adjusted odds ratios (OR) and 95 % confidence intervals (CI) were estimated with logistic regression. RESULTS: Cord blood [25(OH)D] <50 nmol/L was associated with a lower risk of LBW compared to [25(OH)D] ≥75 nmol/L (OR 0.47 95 % CI 0.23-0.97). For 25(OH)D levels 50-75 nmol/L, a significant association was not demonstrated (OR 0.58, 95 % CI 0.34-1.01). No significant associations were observed between [25(OH)D] and either SGA or PTB after adjustment. CONCLUSIONS: Although our findings suggest that [25(OH)D] <50 nmol/L is associated with reduced risk of having a LBW infant, prenatal vitamin D recommendations require an examination of the literature that considers the full spectrum of maternal and neonatal outcomes.