Association Between Gestational Weight Gain and Pregnancy Complications or Adverse Delivery Outcomes in Chinese Han Dichorionic Twin Pregnancies: Validation of the Institute of Medicine (IOM) 2009 Guidelines

Association between gestational weight gain and perinatal outcomes among twin gestations based on the 2009 Institute of Medicine (IOM) guidelines: a systematic review

BACKGROUND

Gestational weight gain (GWG) has been understudied among twin pregnancies. This systematic review aimed to review the data on the associations between GWG, based on the 2009 Institute of Medicine (IOM) guidelines and pregnancy outcomes among twin gestations.

METHODS

A systematic review was performed according to the PRISMA guidelines. A search for eligible studies published from January 2010 to August 2020 was conducted in the EMBASE, PubMed, Web of Science, ScienceDirect, and Cochrane databases. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale. Data on study characteristics and main findings were extracted independently by two reviewers using a standard form. Outcomes of interest included (spontaneous) preterm birth (PTB), gestational hypertensive disorder (gestational hypertension and eclampsia), and small for gestational age (SGA).

RESULTS

Eighteen observational studies of twin gestations met the inclusion criteria. GWG below the IOM recommendations was reported to be associated with increased PTB and SGA while GWG above the recommendation was associated with increased gestational hypertensive disorder. However, the results were inconsistent. Methodological limitations, such as a retrospective design, the use of weekly GWG, a small sample size and insufficient adjustment, impeded the clarification of the association between GWG and perinatal outcomes. In addition, the optimal GWG for underweight women was not fully studied.

CONCLUSIONS

The maintenance of weight gain within the 2009 IOM guidelines would decrease the risks of adverse outcomes among twin pregnancies. However, rigorous studies are warranted to provide robust evidence to refine the optimal GWG among twin gestations.

Gestational weight gain adequacy among twin pregnancies in France

The objective of this paper is to describe gestational weight gain (GWG), to assess the applicability of the 2009 Institute of Medicine (IOM) guidelines, and to derive a GWG adequacy classification within a French cohort. We included twins from the national, prospective, population-based JUmeaux MODe d'Accouchement (JUMODA) cohort study (2014-2015). Following the IOM approach, we selected a 'standard' population of term pregnancies with 'optimal' birthweight (≥2500 g; n = 2562). GWG adequacy (insufficient; adequate; excessive) was defined using IOM recommendations (normal body mass index [BMI]: 16.8-24.5 kg [also utilized for underweight BMI]; overweight: 14.1-22.7 kg; obese: 11.4-19.1 kg). Additionally, using the IOM approach, we determined the 25th and 75th percentiles of GWG in our standard population to create a JUMODA-derived GWG adequacy classification. GWG and GWG adequacy were described, overall and by BMI and parity. In the JUMODA standard population of term twin livebirths with optimal birthweight, mean GWG was 16.1 kg (standard deviation 6.3). Using IOM recommendations, almost half (46.5%) of the women had insufficient and few (10.0%) had excessive GWG, with similar results regardless of BMI or parity. The 25th and 75th percentiles of GWG in the JUMODA standard population (underweight: 13-21 kg; normal weight: 13-20 kg; overweight: 11-19 kg; obese: 7-16 kg) were lower than the IOM recommendations. The IOM recommendations classified a relatively high percentage of French women as having insufficient and a low percentage as having excessive GWG. Additional research to evaluate recommendations in relation to adverse perinatal outcomes is needed to determine whether the IOM recommendations or the JUMODA-derived classification is more appropriate for French twin gestations.

The impact of IOM recommendations on gestational weight gain among US women: An analysis of birth records during 2011-2019

The prevailing guidelines of the Institute of Medicine (IOM) of United States on gestational weight gain (GWG) are based on women's prepregnancy body mass index (BMI) categories. Previous research has shown that the guidelines issued in 1990 and revised in 2009 had no effect. We investigate the effectiveness of new guidelines issued in 2009 analyzing the records of all singleton births in the U.S. during 2011-2019 (34.0 million observations). We use the discontinuity in recommended guidelines at the threshold values of BMI categories in a regression discontinuity (RD) research design to investigate the effect of IOM guidelines on GWG. We also use an RD analysis in a difference in difference (DID) framework where we compare the effect on women who had any prenatal care to others who did not receive prenatal care. The naïve RD estimator predicts an effect in the expected direction at the threshold BMI values of 18.5 and 25.0 but not at 30.0. After the DID based correction, the RD analyses show that the GWG, measured in kg, drop at the BMI values of 18.5, 25.0 and 30.0 by 0.189 [CI: 0.341, 0.037], 0.085 [CI: 0.179, -0.009] and 0.200 [CI: 0.328, 0.072] respectively when the midpoint of the recommended range in kg drops by 1.5, 4.5 and 2.25. This implies a responsiveness of 12.6%, 1.9% and 8.9% respectively to changes in guidelines at these BMI values. The findings show that the national guidelines have induced some behavioral changes among US women during their pregnancy resulting in a change in GWG in the expected direction. However, the magnitude of the change has not been large compared to the expectations, implying that the existing mechanisms to implement these guidelines have not been sufficiently strong.

Gestational weight gain in twin gestations and pregnancy outcomes: a systematic review and meta-analysis

BACKGROUND

Data on the association of inappropriate gestational weight gain (GWG) and adverse outcomes in twin pregnancies are limited and inconsistent.

OBJECTIVES

To perform a systematic review and meta-analysis on the association between GWG and adverse outcomes in twin pregnancies.

SEARCH STRATEGY

Ovid, Medline, EMBASE and Cochrane Central databases from 1 January 1990 until 23 September 2020.

SELECTION CRITERIA

Interventional and observational studies evaluating the association between GWG and adverse outcomes in twin pregnancies.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers. Summary odds ratios (OR) were calculated using a random-effects model in a subset of studies that analysed GWG as a categorical variable in relation to the Institute of Medicine (IOM) recommendations. The primary outcome was preterm birth.

MAIN RESULTS

From 277 citations, 19 studies involving 36 023 women with twin pregnancies were included in the qualitative analysis, of which 14 were included in the meta-analysis. Overall, 56.8% of women experienced inappropriate GWG: 35.4% (95% CI 30.0-41.0%) gained weight below and 21.4% (95% CI 14.2-29.5%) gained weight above IOM recommendations. Compared with GWG within IOM guidelines, GWG below IOM guidelines was associated with preterm birth before 32 weeks of gestation (OR 3.38; 95% CI 2.05-5.58), and a reduction in the risk of pre-eclampsia (OR 0.68; 95% CI 0.48-0.97). GWG above IOM guidelines was associated with an increased risk of pre-eclampsia that was consistent across all body mass index categories.

CONCLUSIONS

Inappropriate GWG affects over half of twin pregnancies, so is a common and potentially modifiable risk factor for preterm birth and pre-eclampsia.

Is Adherence to the Provisional Institute of Medicine Guidelines of Weight Gain Associated With Better Perinatal Outcomes? A Retrospective Cohort Study of Twin Pregnancies in Southwest China

The applicability of the Institute of Medicine (IOM) recommendations of gestational weight gain (GWG) for Chinese twin gestations is uncertain. In this article, we aimed to investigate the associations between GWG among twin gestations, as categorized according to the 2009 IOM guidelines and perinatal outcomes in Chengdu, China. A retrospective cohort study of pregnant women delivering live twins ≥28 weeks at a tertiary maternal and child hospital was conducted. The incidences of perinatal outcomes were compared across 3 groups-that is, women with low, adequate, and excessive GWG. Logistic regression analyses were next performed to confirm the associations while taking into account potential confounders. Results showed that low GWG was associated with a higher risk of preterm birth, low and very low birthweight, neonatal intensive care unit admission, and gestational diabetes, whereas preeclampsia was more frequent among excessive GWG women. In conclusion, adherence to the 2009 IOM guidelines for twin pregnancies are associated with improved perinatal outcomes. This has the potential to improve short- and long-term public health outcomes.

Why Pregnancy Weight Gain Guidelines Need to Differ for Multiple Versus Single Pregnancies

PURPOSE OF THE REVIEW

The purpose of this review was to compare physiological and metabolic changes in singleton and twin gestations and to review pregnancy outcomes with respect to current weight gain guidelines.

RECENT FINDINGS

Reviews in singleton gestations show that weight gain below the recommended guidelines has been associated with small for gestational age infants (less than the 10th percentile) which place these infants at increased risk for neonatal morbidities. Observational studies have shown that adequate and excessive gestational weight gain in twin gestations has been associated with longer gestations and less preterm birth along with increased birth weight at delivery. Weight gain in pregnancy has been identified as a factor that affects both maternal and infant health outcomes in singleton and twin gestations. There is a larger body of research examining these effects in singleton gestations than twin gestations; however, in both groups, the data remain mostly observational and retrospective. Thus far, the research supports the Institute of Medicine recommended weight gain guidelines in singleton and twin gestations for women with normal BMI, but future research should be directed toward underweight and overweight women and the long-term outcomes in all mothers and their offspring.

Gestational Weight Gain in Twin Pregnancies and Maternal and Child Health: An Updated Systematic Review

Background: The Institute of Medicine (IOM) has provisional gestational weight gain (GWG) guidelines for women pregnant with twins due to limited data in this population. To better inform guidelines, the objective of this systematic review was to build on prior work and examine recent data on the associations of GWG with maternal and child health in twin pregnancies. Materials and Methods: In February 2021, Ovid MEDLINE, Embase, CINAHL, and Cochrane Library were searched. Observational studies were eligible if published from January 1, 2013 through February 23, 2021, and examined associations of GWG with maternal or child health outcomes after accounting for gestational age at delivery and pre-pregnancy body mass index. Heterogeneity across studies precluded the use of meta-analytic methods. Results: A total of 29 studies were included. For maternal outcomes, excessive GWG was associated with an increased risk of hypertensive disorders of pregnancy; whereas studies examining gestational diabetes and delivery method reported mixed findings. For child outcomes, inadequate GWG was associated with lower birthweight, small for gestational age, and preterm birth. Adequate or excessive GWG was associated with later gestational age at delivery. Conclusions: This study advances an earlier review by including a more diverse array of maternal and child outcomes. Many of the limitations noted in the original review persist; for example, no studies examined the associations of GWG and outcomes beyond birth. Although it appears that GWG within the IOM guidelines is associated with more optimal outcomes, additional methodologically rigorous studies are needed to better inform evidence-based guidelines.

Perinatal Outcomes and Risk Factors for Preterm Birth in Twin Pregnancies in a Chinese Population: A Multi-center Retrospective Study

Background: Twin pregnancies are associated with an increased risk of adverse maternal and neonatal outcomes, mainly owing to prematurity. Few studies have evaluated the risk factors for preterm birth (PTB) in Chinese population. The objective of this study is to present the short-term maternal-neonatal outcomes, investigating the potential risk factors associated with preterm birth in Chinese twin pregnancies.

Methods: A multi-center retrospective study of women pregnant with twins ≥28 weeks of gestation was conducted. Maternal and neonatal outcomes were analyzed. Logistic regression was used to identify potential risk factors for PTB before 37, 34, and 32 weeks, respectively.

Results: A total of 3,288 twin pregnancies and 6,576 neonates were included in 99,585 pregnancies. The rate of twin pregnancy was 3.3%, while the PTB rate before 37, 34, and 32 weeks among this population were 62.1, 18.8, and 10.4%, respectively. Logistic regression revealed that monochorionicity [Odds ratio (OR) 3.028, 95% confident interval (CI) 2.489–3.683, P < 0.001], gestational weight gain (GWG) <10 kg (OR 2.285, 95% CI 1.563–3.339, P < 0.001) and GWG between 10 and 15 kg (OR 1.478, 95% CI 1.188–1.839, P < 0.001), preeclampsia (PE) (OR 3.067, 95% CI 2.142–4.390, P < 0.001), and intrahepatic cholestasis of pregnancy (ICP) (OR 3.122, 95% CI 2.121–4.596, P < 0.001) were the risk factors for PTB before 37 weeks. Monochorionicity (OR 2.865, 95% CI 2.344–3.501, P < 0.001), age < 25 years (OR 1.888, 95% CI 1.307–2.728, P = 0.001), and GWG <10 kg (OR 3.100, 95% CI 2.198–4.372, P < 0.001) were risk factors for PTB before 34 weeks. Monochorionicity (OR 2.566, 95% CI 1.991–3.307, P < 0.001), age younger than 25 years (OR 1.964, 95% CI 1.265–3.048, P = 0.003), and GWG <10 kg (OR 4.319, 95% CI 2.931–6.364, P < 0.001) were the risk factors for PTB before 32 weeks.

Conclusions: Monochorionicity and GWG <10 kg were two major risk factors for PTB before 32, 34, and 37 weeks, whereas maternal age, PE, and ICP were also risk factors for PTB in specific gestational age.

Gestational Weight Gain and Its Effects on Maternal and Neonatal Outcome in Women With Twin Pregnancies: A Systematic Review and Meta-Analysis

Background: The incidence of twin pregnancies has risen recently. Such pregnancies are associated with an increased risk for poor maternal and infant outcomes. Gestational weight gain, particularly in singleton pregnancies, has been well-linked with maternal and infant outcomes. The aim of the current meta-analysis was to evaluate the effects of gestational weight gain on maternal and fetal outcomes in women with twin pregnancies. Methods: A systematic search was conducted using the PubMed, Scopus, and Google Scholar databases. Studies, either retrospective or prospective in design, evaluating the effects of gestational weight gain (defined using Institute of Medicine (IOM) guidelines) maternal and/or fetal/neonatal outcomes in women with twin pregnancies were included. Statistical analysis was performed using STATA software. Results: Eleven studies were included in the meta-analysis. Mothers with inadequate weight gain had increased risk for gestational diabetes mellitus (OR 1.19; 95% CI: 1.01, 1.40) and decreased risk for gestational hypertension (OR 0.58; 95% CI: 0.49, 0.68) and cesarean section (OR 0.94; 95% CI: 0.93, 0.96). Neonates born to mothers with inadequate weight gain were susceptible to increased risk for preterm delivery (OR 1.17; 95% CI: 1.03, 1.34), very preterm delivery (gestational age <32 weeks) (OR 1.84; 95% CI: 1.36, 2.48), small for gestational age status (OR 1.41; 95% CI: 1.15, 1.72), low birth weight status (<2,500 g) (OR 1.27; 95% CI: 1.17, 1.38), and neonatal intensive care unit (NICU) admission (OR 1.16; 95% CI: 1.08, 1.24). The pooled findings indicate an increased risk for gestational hypertension (OR 1.82; 95% CI: 1.60, 2.06) and cesarean section (OR 1.07; 95% CI: 1.05, 1.08) among mothers with excessive weight gain. Neonates born to mothers with excessive weight gain were susceptible to increased risk for preterm delivery and very preterm delivery, but were associated with a decreased risk for low birth weight status and small for gestational age status. Conclusions: Gestational weight gain in twin pregnancy, either lower or higher than IOM recommended guidelines, is associated with poor maternal and neonatal outcomes. Our findings call for incorporating counseling on optimal weight gain during pregnancy as part of routine antenatal visits.

A cohort study of fetal growth in twin pregnancies by chorionicity: comparison with European and American standards

OBJECTIVE

To develop fetal growth standards for twin gestations by placental chorionicity in a Spanish population and compare them with European and American standards to estimate the suitability of their use in clinical practice.

STUDY DESIGN

This was a retrospective cohort study of 518 twin pregnancies, 435 dichorionic-diamniotic and 83 monochorionic-diamniotic, performed between January 2012 and December 2017. A total of 4,783 and 1,455 estimated fetal weights were considered from the 17^th to the 37^th week of gestation, using multilevel models, to build dichorionic-diamniotic and monochorionic-diamniotic standards, respectively. The percentages of small and large for gestational age were calculated as a model adjustment measure and adjustment to the studied data and the values provided by our model were compared against those of six European and American twin standards and three singleton standards. Correlation analyses between percentile predictions were performed using Cohen kappa coefficient. The predictive ability to detect small for gestational age was also provided by the sensitivity and positive predictive value.

RESULTS

We found slight differences between standards by chorionicity, being dichorionic-diamniotic percentiles slightly higher than monochorionic-diamniotic ones from the 17^th to 37^th weeks' gestation. For dichorionic-diamniotic cases, both our standard (9.8-8.2) and that of Grantz (8.2-10.5) showed good adjustments for the 10^th and 90^th percentiles while the other compared standards underestimated or overestimated them. For monochorionic-diamniotic cases, both our standard (10.2-8.5) and that of Shivkumar (11.4-6.8) had the most suitable adjustment. The correlation analysis between small and large for gestational age cases provided by standards, showed clear differences among them. Kappa's coefficient showed a substantial agreement between both Ananth (0.7) and Stirrup (0.69) dichorionic-diamniotic cases and our standard. There was also a substantial agreement between the Shivkumar (0.77) standard and our results for monochorionic-diamniotic cases. The correlation was moderate for all other comparisons.

CONCLUSIONS

Our model showed a good adjustment to the studied population. There are clear differences among small and large for gestational age cases provided by twin standards in our studied population. The twin growth standards depend on the population characteristics and model structure. We found the use of singleton standards for twin pregnancies inadequate.

Optimal Gestational Weight Gain for Tibetans Based on Prepregnancy Body Mass Index

We aimed to estimate the optimal gestational weight gain (GWG) in Tibetan women and to evaluate the appropriateness of the Institute of Medicine (IOM) GWG recommendations for Tibetan women. We analyzed data from 1474 Tibetan women from a cross-sectional study conducted in 2019. According to the three different body mass index (BMI) classification criteria (WHO BMI categories, WHO Asian BMI categories, Chinese BMI categories), we estimated the association of GWG with pregnancy outcomes (neonate birthweight and mode of delivery) using a polynomial regression model, and the optimal GWG in each BMI group was calculated. The risk of adverse outcomes showed a U-shaped curve with increasing GWG. The optimal GWG of Tibetan women based on the WHO BMI categories was 17.2 kg (range, 13.3 to 20.9 kg) for underweight, 9.3 kg (5.8 to 12.9 kg) for normal weight, and 5.2 kg (1.3 to 9.1 kg) for overweight. Underweight Tibetan mothers may gain more gestational weight than recommend by the IOM guidelines. However, normal weight Tibetan mothers are likely to benefit from gaining less weight than that recommended by the IOM. The GWG recommendations based on the IOM guidelines might not be appropriate for Tibetan women, and ethnicity-specific recommendations for GWG should be properly addressed.

Excessive gestational weight gain and the risk of gestational diabetes: Comparison of Intergrowth-21st standards, IOM recommendations and a local reference

AIMS

To compare the abilities of Intergrowth-21st standards, Institute of Medicine (IOM) recommendations and a Chinese reference on gestational weight gain (GWG) to identify women at risk of gestational diabetes (GDM) and GDM-related adverse outcomes.

METHODS

A retrospective cohort study was conducted on 13,366 women delivering live singleton infants between 2013 and 2017 in Tongzhou district of Beijing, China. Poisson regression with robust error estimates was used to estimate risk ratios (RRs) of GDM in different GWG groups according to three standards.

RESULTS

There were 39.97%, 46.31% and 30.03% of women gaining weight above Intergrowth-21st standards, IOM recommendations and the Chinese reference respectively. Women with GWG above Intergrowth-21st standards and the Chinese reference had 27% (aRR, 1.27 95% CI, 1.18-1.37) and 30% (aRR, 1.30; 95% CI, 1.21-1.40) increased risks of GDM respectively, as compared to 22% (aRR, 1.22; 95% CI, 1.13-1.32) for IOM recommendations. GWG above either of these three standards was associated with macrosomia and cesarean delivery (P < 0.05).

CONCLUSION

Compared with IOM recommendations, GWG above Intergrowth-21st standards or the Chinese reference was associated with higher risks of GDM and GDM-related adverse outcomes. Furthermore, these two prospective standards could additionally assess the severity of abnormal GWG and are feasible for dynamic monitoring.

The gestational weight gain and perinatal outcomes among underweight women with twin pregnancies: Propensity score matched analysis from a three-year retrospective cohort

OBJECTIVE

No recommendations are available for gestational weight gain (GWG) in underweight women with twin pregnancies. We aimed to evaluate whether underweight women with twin pregnancies should gain more weight than normal-weight women in order to optimize perinatal outcomes.

STUDY DESIGN

This retrospective cohort study compared the GWG and perinatal outcomes among normal-weight and underweight women who gave birth to viable twins between 2015 and 2018 at the Maternal and Child Health Hospital in Foshan, China. Gestational weight gain (GWG) was categorized as adequate or inadequate GWG, based on the US Institute of Medicine 2009 guidelines for normal-weight women (≥ 0.46 kg/week). The outcomes of interest included spontaneous preterm birth (sPTB) <37 weeks, <35 and <32 weeks, small for gestational age (SGA), gestational hypertensive disorder (GHD), gestational diabetes mellitus (GDM), birth weight discordance (BDW) ≥20%, neonatal intensive unit (NICU) admission and neonatal respiratory distress syndrome (NRDS). Propensity score matching (PSM, in a 1:1 ratio) was utilized to minimize the effects of confounders on the differences in the two cohorts. Multivariable logistic models were also used to verify the results from PSM analysis.

RESULTS

There were 475 normal-weight and 111 underweight women included in the analysis. Our results suggested that the incidence of adequate GWG was comparable between underweight and normal-weight women (37.5% vs. 45.1%, P = 0.141). The prevalence of GDM was significantly lower among underweight women (9.9%) than among normal-weight women (20.4%) (P = 0.010). There was no evidence of differences in other perinatal outcomes between the two groups. 102 underweight women and 102 normal-weight women were included in PSM analyses. There was a lower incidence of GDM in underweight women than in normal-weight women, but the difference was not significant (9.8% vs. 18.6%, P = 0.071). No evidence of any differences in the other outcomes, including sPTB, GHD, BWD≥20%, SGA, NICU admission and NRDS, was found between the underweight and normal-weight women. Multivariable logistic regression models yielded similar results.

CONCLUSIONS

For Chinese twin pregnant women with twin pregnancies, our data does provide evidence to suggest underweight women need to gain more weight than normal-weight women to optimize perinatal outcomes. Future studies with larger number of underweight women with twin gestations are warranted to establish an optimal range of GWG.

Effect of maternal weight gain according to the Institute of Medicine recommendations on pregnancy outcomes in a Chinese population

Objective

This study aimed to analyze the effects of maternal weight on adverse pregnancy outcomes.

Methods

Data were retrospectively collected from a hospital in Wuhan, China. A total of 1593 pregnant women with singletons were included. Adverse outcomes during pregnancy, such as small for gestational age (SGA), large for gestational age (LGA), and hypertensive disorders in pregnancy (HDP) were analyzed.

Results

The risks of low birth weight, SGA, and preterm birth were significantly higher in the inadequate gestational weight gain (GWG) group compared with the adequate GWG group. GWG over the guidelines was related to a higher risk of macrosomia, LGA, cesarean section, and HDP than GWG within the guidelines. The risks of low birth weight (OR = 5.082), SGA (OR = 3.959), preterm birth (OR = 3.422), and gestational diabetes mellitus (OR = 1.784) were significantly higher in women with a normal pre-pregnancy body mass index (BMI) and inadequate GWG compared with women with a normal pre-pregnancy BMI and adequate GWG. The risks of macrosomia (OR = 3.654) and HDP (OR = 1.992) were increased in women with normal pre-pregnancy BMI and excessive GWG.

Conclusion

Women with an abnormal BMI and inappropriate GWG have an increased risk of adverse maternal and infant outcomes. Weight management during the perinatal period is required.

The effect of gestational weight gain on perinatal outcomes among Chinese twin gestations based on Institute of Medicine guidelines

BACKGROUND

Gestational weight gain (GWG) has implications for perinatal outcomes, the guidelines for maternal weight gain, however, remain understudied among twin pregnancies. This study aimed to assess the associations between perinatal outcomes and GWG among twin pregnancies, based on the US institute of Medicine (IOM) 2009 guidelines.

METHODS

A retrospective cohort study of pregnant women with viable twins ≥26 weeks of gestation, was conducted in Foshan, China, during July 2015 and June 2018. Maternal BMI was categorized based on Chinese standard and GWG was categorized as below, within and above the IOM 2009 recommendations. Underweight women were excluded for analysis. Perinatal outcomes were compared among these groups. To assess the independent impact of GWG on the perinatal outcomes, conventional multivariable regression and general estimated equation (GEE) were utilized for maternal outcomes and neonatal outcomes, respectively.

RESULTS

A total of 645 mothers with twin pregnancies were included, of whom 15.0, 41.4 and 43.6% gained weight below, within and above guidelines, respectively. Compared to weight gain within guidelines, inadequate weight gain was associated with increased risks in spontaneous preterm birth < 37 weeks (aOR:3.55; 95% CI: 1.73-7.28) and < 35 weeks (aOR:2.63; 95% CI: 1.16-5.97). Women who gained weight above guidelines were more likely to have gestational hypertension disorder (aOR: 2.36; 95% CI: 1.32-4.21), pre-eclampsia (aOR: 2.59; 95% CI: 1.29-5.21) and have fetuses weighted >90th percentile and less likely to have fetuses weighted < 2500 g and < 1500 g.

CONCLUSIONS

Maintenance of gestational weight gain within the normal range could decrease the risk of adverse perinatal outcomes. However, the causality between pre-eclampsia and gestational weight gain requires further investigations.