Underweight Prepregnancy Body Mass Index Research Articles

Risk factors and glycaemic control in small-for-gestational-age infants born to mothers with gestational diabetes mellitus: a case–control study using propensity score matching based on a large population

BackgroundSmall for gestational age (SGA) poses a significant concern for newborns, being linked to neonatal complications and potential metabolic disorders in adulthood, especially when born to mothers with gestational diabetes...

Adverse live-born pregnancy outcomes among pregnant people with anorexia nervosa

BackgroundPrevious findings related to the association of adverse pregnancy outcomes among people with anorexia nervosa are mixed. ObjectivesTo investigate the association of adverse live born pregnancy outcomes among people with anorexia nervosa using adjustment modeling accounting for confounding factors, as well as a mediation analysis addressing the contribution of underweight pre-pregnancy body mass index and gestational weight gain to those same outcomes. Study designThe sample included California live born singletons with births between 2007 and 2021. The administrative dataset contained birth certificates linked to hospital discharge records. Anorexia nervosa diagnosis during pregnancy was obtained from International Classification of Diseases codes on hospital discharge records. Adverse pregnancy outcomes examined included gestational diabetes, gestational hypertension, preeclampsia, anemia, antepartum hemorrhage, premature rupture of the membranes, premature labor, cesarean delivery, oligohydramnios, placenta previa, chorioamnionitis, placental abruption, severe maternal morbidity, small for gestational age, large for gestational age, low birthweight, and preterm birth (by timing and indication). Risk of each adverse outcome was calculated using Poisson regression models. Unadjusted risk of each adverse outcome was calculated, then risks were adjusted for demographic factors, and the final adjusted model included demographic factors, anxiety, depression, substance use, and smoking. A mediation analysis was preformed to estimate the excess adverse outcome mediated by underweight pre-pregnancy body mass index and gestational weight gain below the ACOG recommendation. ResultsThe sample included 241 pregnant people with a diagnosis of anorexia nervosa and 6,418,236 pregnant people without an eating disorder diagnosis. An anorexia nervosa diagnosis during pregnancy was associated with many adverse pregnancy outcomes in unadjusted models (relative risks ranged from 1.65 (preeclampsia) to 3.56 (antepartum hemorrhage)) compared to people without an eating disorder diagnosis. In the final adjusted models, birthing people with an anorexia nervosa diagnosis were more likely to have anemia, preterm labor, oligohydramnios, severe maternal morbidity, a small for gestational age or low birthweight infant, and a preterm birth between 32 and 36 weeks with spontaneous preterm labor (adjusted relative risks ranged from 1.43 to 2.55). Underweight pre-pregnancy body mass index mediated 7.78% of the excess in preterm births and 18.00% of the excess in small for gestational age infants. Gestational weight gain below the recommendation mediated 38.89% of the excess in preterm births and 40.44% of the excess in low birthweight infants. ConclusionsAnorexia nervosa diagnosis during pregnancy was associated with a number of clinically important adverse pregnancy outcomes compared to people without an eating disorder diagnosis. Adjusting for anxiety, depression, substance use, and smoking during pregnancy decreased this risk. A substantial percent of the excess risk of adverse outcomes was mediated by an underweight pre-pregnancy body mass index; while a larger proportion of excess risk was mediated by gestational weight gain below the recommendation. This information is important for clinicians to consider when caring for patients with anorexia nervosa. Considering and treating anorexia nervosa and comorbid conditions and counseling patients about mediating factors like pre-conception weight and gestational weight gain may improve pregnancy live birth outcomes among people with anorexia nervosa.

Trends and associations between maternal characteristics and infant birthweight among Indigenous and non-Indigenous people in Tasmania, Australia: a population-based study

ObjectiveThis study aimed to investigate the trends and associations of maternal characteristics and birthweight among Indigenous and non-Indigenous infants. Study designThis was a retrospective population-based study. MethodsFourteen years (2005–2018) of birthweight and perinatal health data of live-born singletons and their mothers obtained from the Tasmanian Data Linkage Unit were used to assess the trends and associations between maternal characteristics and infant birthweight using regression modelling. ResultsCompared with non-Indigenous mothers (n = 76,750), Indigenous mothers (n = 3805) had a significantly higher prevalence of risk factors during the 14-year period. Although the prevalence of prepregnancy obesity and gestational diabetes mellitus (GDM) markedly increased in both groups, the rate of increase was higher (P < 0.001) for Indigenous than non-Indigenous mothers. Smoking, alcohol consumption and illegal drug use during pregnancy reduced over the years, and there was no significant difference in the rate of reduction between the groups. Large-for-gestational-age (LGA) births increased while small-for-gestational-age (SGA) births decreased in both groups over time. In addition, high birthweight (HBW) births decreased while low birthweight (LBW) births increased. The rates of increase in LGA and LBW births and the rates of decrease in SGA and HBW births were significantly higher in Indigenous mothers compared with non-Indigenous mothers (P < 0.001 for all). The association between Indigenous ethnicity and LBW and SGA births weakened after adjusting for other confounding maternal and perinatal variables. LBW and SGA were positively associated with Indigenous ethnicity, age <18 years, smoking, alcohol consumption and illegal drug use, pre-eclampsia, underweight prepregnancy body mass index and low socio-economic status. Women with higher parity, pre-existing diabetes and prepregnancy overweight or obesity were more likely to give birth to an infant with HBW or LGA. ConclusionsThe prevalence of risk factors for abnormal birthweight is higher among Tasmanian Indigenous mothers, contributing to a gap in birthweight outcomes between Indigenous and non-Indigenous infants. The dramatic increase in prepregnancy obesity and GDM in both groups highlight the importance of screening and management of GDM during pregnancy. Comprehensive programmes co-designed and co-managed in consultation with Indigenous people are needed to support healthy lifestyle choices among Indigenous women to address the barriers to individuals adopting behaviour change and to help close the health outcomes–related gap between Indigenous and non-Indigenous mothers and infants.

Maternal pre-pregnancy anemia and childhood anemia in Indonesia: a risk assessment using a population-based prospective longitudinal study.

Anemia in children under 5 years of age is often overlooked despite its detrimental effects. The public health approach to anemia prevention includes the maternal pre-pregnancy phase. This study investigated the association between pre-pregnancy anemia and the risk of anemia in children under 5 years of age. This cohort study included non-pregnant women from the 2007 Indonesian Family Life Survey (IFLS) and their children under 5 in the 2014 IFLS. The anemia status of mothers and children was determined based on hemoglobin (Hb) levels using Hemocue. Mantel-Haenszel adjusted relative risks (aRRs), including risk stratification by covariates, were used for the final risk assessment. In total, 637 children in the 2014 IFLS were included. The risk of having a child with anemia was 1.71-fold higher in women with pre-pregnancy anemia than in women without pre-pregnancy anemia (aRR, 1.71; 95% confidence interval [CI], 1.03 to 2.85). After risk stratification based on potential confounding variables, maternal pre-pregnancy anemia remained an independent risk factor for anemia in children who still breastfed at the time of data collection (relative risk [RR], 2.11; 95% CI, 1.16 to 3.86), in children who were given water earlier than 6 months of age (RR, 2.08; 95% CI, 1.20 to 3.61), in children of mothers with a normal or underweight pre-pregnancy body mass index (RR, 1.94; 95% CI, 1.20 to 3.14), and in children of mothers without current anemia (RR, 2.20; 95% CI, 1.21 to 3.99). Pre-pregnancy anemia increased the risk of childhood anemia. A public health approach emphasizing pre-conception maternal health would enable better maternal and child morbidity risk prevention.

Maternal Nutrition and Inadequate Gestational Weight Gain in Relation to Birth Weight: Results from a Prospective Cohort Study in India.

Inadequate/excessive gestational weight gain (GWG) can cause adverse pregnancy outcomes and only few studies have described patterns of weight gain in Indian women. Also, studies pertaining to dietary intake throughout gestation are insufficient. This prospective cohort study was conducted to evaluate GWG and nutrient intake in all trimesters of pregnancy and investigate the relationship between themselves along with that of birth weight (BW). Our study was carried out in a population-based prospective birth cohort in Odisha, India. The 418 pregnant women were followed till delivery with measurements of maternal weight, weight gain throughout gestation, and BW. Macronutrients were assessed based on a 24-hour dietary recall method in each trimester. Women characterized by under-weight pre-pregnancy body mass index (BMI) were 16.20%, and a total of 6.45% did not comply with current weight gain recommendations. Particularly, overweight and obese women gained more weight than recommended. In a multivariate analysis GWG correlated significantly with BMI (p = 0.03), total calorie intake (p < 0.001) and fat intake (p < 0.001), while BW of newborns correlated significantly with adequacy of weight gain and fat intake (p < 0.001). Though measures are taken by health workers to record the weight but nutritional counseling is not being provided regularly. A high priority should be given to increase awareness among general population regarding the importance of diet in pregnancy and how to adhere to the balanced diet for optimal growth of child.

Weight gain and pregnancy outcomes in underweight women with twin gestations

Background: Adherence to minimum weight gain recommendations in twin pregnancies as defined by the Institute of Medicine (IOM) guidelines is associated with improved pregnancy outcomes; however, these recommendations have yet to be made for underweight women (BMI < 18.5 kg/m2).Objective: To determine if existing pregnancy weight gain recommendations in twin gestations apply to women with underweight prepregnancy body mass index (BMI), and if these women have similar pregnancy outcomes to women with normal prepregnancy BMI.Methods: This is a retrospective cohort study of women with underweight (BMI < 18.5 kg/m2) and normal prepregnancy BMI (18.5–24.9 kg/m2) and twin pregnancies delivered > 24 weeks by a single Maternal Fetal Medicine (MFM) practice between 2005–2017. Weight gain patterns and pregnancy outcomes were compared between women with underweight prepregnancy BMI and normal prepregnancy BMI. The primary outcomes of the study were gestational age at delivery and intrauterine growth restriction.Results: A total of 664 women met inclusion criteria during the study period, 55 (8.3%) of whom had an underweight prepregnancy BMI, and 609 (91.7%) of whom had a normal prepregnancy BMI. There were no differences in baseline clinical and demographic characteristics between the groups, nor any differences in overall weight gain or weight gain patterns between the two groups. There were no significant differences between the groups in birthweight of the larger twin (2415 versus 2489 g, p = .26) or the smaller twin (2150 versus 2190 g, p = .55), gestational age at delivery (35.8 versus 35.8 weeks, p = .96), incidence of preterm birth < 34 weeks (16.4 versus 16.3%, p = .98), spontaneous preterm birth < 34 weeks (9.1 versus 11.7%, p = .57), or the incidence of either twin with a birthweight < 10% for gestational age (60.0 versus 56.0%, p = .57) or < 5% for gestational age (36.4 versus 30.9%, p = .40).Conclusions: Women with underweight prepregnancy BMI who gain equal weight to women with normal prepregnancy BMI have similar pregnancy outcomes. The recommendations for adequate weight gain in women with underweight prepregnancy BMI should therefore not exceed those for women with normal prepregnancy BMI.

Risk factors for congenital microcephaly in the pre-Zika era.

The Zika epidemic has brought increased attention to congenital microcephaly as a birth outcome. However, little is known about risks for microcephaly unrelated to Zika. Using data from the Slone Epidemiology Center Birth Defects Study from 1993 to 2015, we identified 57 cases of microcephaly alone ("isolated") and 109 cases of microcephaly that included other major birth defects ("non-isolated"), and considered a large number of potential risk factors including demographic characteristics, illnesses, and medications used during pregnancy. Where numbers permitted, we used logistic regression models to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Substantial differences in risk factors were observed for isolated versus non-isolated microcephaly. For isolated microcephaly, risk estimates were elevated for mothers of non-Hispanic, non-White race/ethnicity, and underweight pre-pregnancy body mass index (BMI). The risk for exposure anytime in pregnancy to acetaminophen was null; in contrast, the aOR for NSAIDs was 2.4 (95% CI: 1.3-4.2). This association was weakened (but not eliminated) after excluding those exposed to opioids or illicit drugs, and risk was not present among those reporting less frequent exposures. For non-isolated microcephaly, elevated risk estimates were found for urinary tract infection. Risk factors differed for isolated and non-isolated microcephaly. While some findings support previously reported associations, (e.g., smoking, alcohol, underweight BMI), we also identified risk factors not previously described, notably NSAID use for isolated microcephaly and urinary tract infection for non-isolated microcephaly; however, these results should be viewed as hypothesis generating.

Maternal Prepregnancy Body Mass Index and Small for Gestational Age Births in Chinese Women.

Both high and low prepregnancy body mass index (BMI) has been associated with small for gestational age births (SGA; birthweight below the population specific 10th centile for the gestational age), but results remain inconsistent. We examined the association between maternal BMI and SGA, and evaluated if the associations were modified by preterm birth (being born prior to 37 weeks) status. A population-based cohort study was conducted in Wuhan, China from June 2011, to June 2013. Women who delivered a non-malformed livebirth (n = 76 695) were included using the Wuhan Maternal and Child Health Management Information System. Log-binomial regression models were used to analyse the associations between prepregnancy BMI, categorized using thresholds adapted to the Chinese population, and SGA. Stratified analyses were used to examine the relationship of prepregnancy BMI to preterm-SGA and term-SGA. Of the 76 695 live births, 3058 (4.0%) were delivered preterm. For babies born at term, prepregnancy underweight (<18.5 kg/m2 ) was associated with an increased risk of SGA, the adjusted risk ratio (RR) was 1.41 (95% confidence interval (CI) 1.33, 1.49), whereas, being overweight (24.0-27.9 kg/m2 ) was associated with a decreased risk (RR 0.84, 95% CI 0.74, 0.94). For babies born preterm, prepregnancy underweight was not associated with risk of SGA, but being overweight was associated with an increased risk (RR 1.57, 95% CI 1.04, 2.35). These data suggest that the association of overweight and underweight prepregnancy BMI and SGA differs depending on whether the baby is full term or preterm.

Pre-Pregnancy Weight Status Is Associated with Diet Quality and Nutritional Biomarkers during Pregnancy

Although the positive association between pre-pregnancy overweight and obesity with excessive gestational weight gain is well known, it is not clear how pre-pregnancy weight status is associated with gestational weight gain through maternal diet during pregnancy. This study aimed to examine the relationship between pre-pregnancy weight status and diet quality and maternal nutritional biomarkers during pregnancy. Our study included 795 U.S. pregnant women from the National Health and Nutrition Examination Survey, 2003–2012. Pre-pregnancy body mass index (BMI) was calculated based on self-reported pre-pregnancy weight and height. The cutoff points of <18.5 (underweight), 18.5–24.9 (normal), 25.0–29.9 (overweight), and 30 kg/m2 (obese) were used to categorize pregnant women’s weight status. Diet quality during pregnancy was assessed by the Healthy Eating Index (HEI)-2010 based on a 24-h recall. Multivariable logistic regressions were used to estimate the odds ratios (OR) and 95% confidence intervals (CI). For all pregnant women included in this study, the mean HEI-2010 (±standard error of the mean (SEM)) was 50.7 (±0.9). Women with obese pre-pregnancy BMI demonstrated significantly lower HEI-2010 compared to those with underweight and normal pre-pregnancy BMI, respectively. In an unadjusted model, women with pre-pregnancy obesity BMI had increased odds for being in the lowest tertile of HEI-2010 (33.4 ± 0.5) compared to those with underweight pre-pregnancy BMI (OR 5.0; 95% CI 2.2–11.4). The inverse association between pre-pregnancy overweight and obesity status and diet quality during pregnancy persisted even after we controlled for physical activity levels (adjusted OR (AOR) 3.8; 95% CI 1.2–11.7, AOR 5.4; 95% CI 2.0–14.5, respectively). Serum folate concentration (ng/mL) was significantly higher in underweight women compared to overweight women (23.4 ± 1.7 vs. 17.0 ± 0.8, p < 0.05). Serum iron concentration (ng/dL) was significantly higher in normal weight women compared to overweight women (86.2 ± 5.0 vs. 68.9 ± 3.0, p < 0.05). An inverse association was found between pre-pregnancy weight status and diet quality and maternal nutritional biomarkers during pregnancy. Poor diet quality as measured by HEI-2010 was shown among overweight and obese women. Nutrition education and interventions need to be targeted to those women entering pregnancy as overweight and obese.

Parental Body Mass Index, Gestational Weight Gain, and Risk of Macrosomia: a Population-Based Case-Control Study in China.

The prevalence of macrosomia has risen markedly worldwide, including in China, during the past two decades. Few epidemiological studies, however, have investigated the risk factors for macrosomia in China. This study was designed to investigate the associations between parental anthropometric characteristics, gestational weight gain (GWG), and risk of macrosomia in China. This population-based, case-control study in Wuhan, China, included a total of 6341 subjects (870 cases and 5471 controls). Multivariable logistic regression was conducted to calculate odds ratios (OR) and 95% confidence intervals (CI). Mothers or fathers who were overweight or obese before pregnancy had an elevated risk of giving birth to a macrosomic infant compared with their normal weight counterparts. Women with GWG above the Institute of Medicine (IOM) recommendation had an adjusted OR of 6.09 [95% CI 5.04, 7.35] for delivering a macrosomic infant compared with women who had GWG within the IOM recommendation. When stratified by maternal pre-pregnancy body mass index (BMI), women who were underweight or normal weight before pregnancy were observed to have a higher risk of macrosomia birth associated with greater GWG. Parental pre-pregnancy overweight/obesity and excessive GWG during pregnancy were highly associated with macrosomia. The association with GWG was most pronounced in mothers who had a normal or underweight pre-pregnancy BMI. Weight control efforts before pregnancy for mothers and fathers as well as control of maternal gain during pregnancy may reduce the risk of macrosomia.

Prepregnancy body mass index is an independent risk factor for gestational hypertension, gestational diabetes, preterm labor, and small- and large-for-gestational-age infants

Objective: We examined if prepregnancy body mass index (BMI) is a risk factor for gestational hypertension, gestational diabetes, preterm labor, and small-for-gestational-age (SGA) and large-for-gestational-age (LGA) infants with consideration of gestational weight gain, to document the importance of preconception versus prenatal stage.Methods: We used the data of 219 868 women from 2004 to 2011 Pregnancy Risk Assessment Monitoring System (PRAMS). Multivariate logistic regression analyses were performed to examine the effect of prepregnancy BMI for gestational hypertension, gestational diabetes, preterm labor, and SGA and LGA infants with consideration of gestational weight gain.Results: Regardless of gestational weight gain, women with obese prepregnancy BMI (≥30 kg/m2) had increased odds of gestational hypertension (adjusted odds ratios (AOR) = 2.91; 95% CI = 2.76–3.07), gestational diabetes (2.78; 2.60–2.96), and LGA (1.87; 1.76–1.99) compared to women with normal prepregnancy BMI (18.5–24.9 kg/m2). Women with underweight prepregnancy BMI (<18.5 kg/m2) had increased odds of preterm labor (1.25; 1.16–1.36) and SGA infants (1.36; 1.25–1.49), but decreased odds of LGA infants (0.72; 0.61–0.85) in reference to women with normal prepregnancy BMI (18.5–24.9 kg/m2).Conclusions: Regardless of adequacy of gestational weight gain, the risk of gestational hypertension, gestational diabetes, and LGA infants increases with obese prepregnancy BMI, whereas that of preterm labor and SGA infants increases with underweight prepregnancy BMI. Preconception care of reproductive aged women is as important as prenatal care to lower the risk of gestational hypertension, gestational diabetes, preterm labor, and SGA and LGA infants.

Factors Influencing on Perinatal Outcomes of Asian Marriage Immigrant Women: Ten-year Experience in a Single Center

Purpose : We aimed to analyze the maternal and perinatal factors associated with perinatal outcomes by exa­ mining families comprised of Korean fathers, Asian immigrant mothers, and their newborns. Method : Medical records of newborn infants admitted to Jeonju Jesus Hospital nursery or ne­onatal intensive care unit (NICU) from January 2004 to June 2013 and their Asian immigrant mothers were reviewed retro­ spec tively. The newborns were divided into two groups depending on whether they were admitted NICU or not, and factors influencing on perinatal outcomes were compared between the two groups. The newborn were divided into the two groups, including those who did not receive inpatient care and those treated in the NICU. The differences between the two groups were analyzed. Results : The study included 180 newborns and 172 mothers, and 94 (52.3%) and 86 (47.7%) newborns were classified as the nursery group and the NICU group, respectively. There were no statistically significant diffe­ rences between the two groups in terms of the mothers’ nationality, maternal age, maternal education level, maternal occupation, residential area, maternal height and weight, maternal weight gain during pregnancy, maternal hepatitis B antigen positivity, maternal parity, paternal age, and age gap between spouses. However, underweight maternal prepregnancy body mass index (BMI) and hemoglobin level over 11.0 g/dL were signi­ ficantly more frequent in the NICU group in the comparative analysis. The NICU group showed significantly more frequent no iron supplements during pregnancy (OR=4.06) and gestational disease (OR=3.81). Conclusion : In cases where married immigrant mothers had underweight prepregnancy BMI, gestational dis­ ease, or no iron supplements during pregnancy, their newborns were more likely to have NICU care. Therefore, married immigrant women should have appropriate perinatal care including education about a balanced diet to maintain an appropriate body weight with ensuring an adequate iron supplements intake.

Risk factors for recurrent preterm birth in multiparous Utah women: a historical cohort study

To describe risk factors for recurrent preterm birth (PTB) in the second and third birth. Historical cohort study. Utah, USA. Women who had their first three singleton live births in Utah between 1989 and 2007 and a preterm first or second birth were included. Maternally linked birth records were used. Multivariable-adjusted risk ratios were calculated for recurrent PTB. Results were stratified by spontaneous and indicated PTB and by pattern of birth outcomes. Risk ratios and 95% confidence intervals for risk factors for recurrent PTB. Among women with PTB in their first or second live birth, recurrent PTB occurred in 21% of second live births (n=1011/4805) and 22% of third live births (n=1872/8468). Risk factors for recurrence included short inter-pregnancy interval, underweight prepregnancy body mass index, pre-existing maternal medical conditions, history of PTB at 28-32weeks of gestation (versus 33-36weeks), the presence of a fetal anomaly, and young maternal age. Risk factors for spontaneous, but not indicated PTB included young maternal age and less than appropriate gestational weight gain. Risk factors also varied in women experiencing a first versus second recurrence in their third birth. Risk factors may vary by the clinical subtype of the most recent PTB and the pattern of term and preterm outcomes across births 1-3; some of the risk factors identified in this study may be modifiable through interventions targeted at women in the inter-conception period.

Predictors and adverse outcomes of inadequate or excessive gestational weight gain in an Asian population

The aim of this study was to assess maternal characteristics as predictors of inadequate or excessive gestational weight gain (GWG) and to characterize maternal and neonatal outcomes associated with inadequate or excessive GWG in Asian women. A study was conducted among 1166 Chinese, Malay, and Indian women who delivered a live singleton infant at KK Women's and Children's Hospital, Singapore. Logistic regression analysis was used to determine predictors and maternal and neonatal outcomes of inadequate or excessive GWG, relative to adequate (recommended) GWG. While maternal age less than 20 years, Malay ethnicity and underweight pre-pregnancy body mass index increased the risk of inadequate GWG, overweight pre-pregnancy body mass index decreased this risk. Tall stature and Malay ethnicity were associated with an increased risk of excessive GWG, while maternal age greater than 30 years was associated with a decreased risk. Inadequate GWG increased the risk of preterm birth and decreased the risk of delivery by cesarean section and postpartum weight retention at 6 months. Excessive GWG increased the risk of delivery by cesarean section, postpartum weight retention at 6, 12 and 24 months and having a high-birthweight baby. Maternal predictors and perinatal outcomes of GWG among Asian women are similar to those identified previously among Caucasian, African-American and Hispanic women.

Determinants of Small for Gestational Age Birth at Term

Being born small for gestational age (SGA) is an indicator of intrauterine growth restriction (IUGR) and later health risks. This study investigated determinants of severe and moderate SGA (respectively, birthweight <3rd percentile and 3rd to <10th percentile for gestational age and sex). A total of 2195 term pregnancies from a prospective cohort were studied. Prenatal data arose from maternal interview at 10-22 weeks of gestation and perinatal data were collected from hospital charts. Severe and moderate SGA were classified by Canadian population standards. Risk factors for SGA were identified from fitting multivariable logistic regression models. Multivariable associations with severe SGA were: maternal age ≥ 35 [odds ratio (OR) 3.2 [95% confidence interval (CI) 1.4, 6.9]], maternal smoking during pregnancy (OR 5.3 [95% CI 2.4, 11.7]), preeclampsia (OR 4.6 [95% CI 1.6, 13.2]) and threatened preterm labour (OR 3.9 [95% CI 1.3, 11.4]). Primiparity was associated with both severe and moderate SGA with OR 2.4 [95% CI 1.1, 5.1] and OR 1.9 [95% CI 1.3, 2.9] respectively. Underweight pre-pregnancy body mass index was associated with moderate SGA (OR 2.4 [95% CI 1.2, 5.0]). Inclusion of placental weight, in the final model attenuated the associations. This study demonstrated different determinants for severe and moderate SGA. We speculate that the majority of severe SGA infants are IUGR while moderate SGA infants may be a mixture of IUGR and constitutionally small newborns. This study has also contributed evidence linking preterm labour and SGA as two, potentially related, outcomes of overlapping causal mechanisms reflective of ischaemic placental disease.