PregnancyGWG HDPNCT07902232
Gestational Weight Loss and Restrictive Weight Gain in Maternal Obesity: A Target Trial Emulation
An observational study of Pregnancy and Obesity, run by Shanghai First Maternal and Infant Health Hospital affiliated to Tongji University Medical School at 1 site in China.
Trial summary
This study asks whether the current weight-gain guideline for pregnant people with obesity should be lowered, and whether the answer depends on how severe the obesity is. The guideline from the Institute of Medicine (IOM) recommends that all pregnant people with obesity gain 5.0 to 9.0 kg, regardless of obesity class. Read more about this study
- Who is it for?
- Ages 18 to 45 years, women only
- Conditions the study is for
- Pregnancy, Obesity, Gestational Hypertension
- What is being tested?
- Gestational Weight Gain (GWG) Strategy
- How many people
- 205,636 participants
- Where
- 1 siteChina
- Study dates
- 1 Jan 2026to 19 Oct 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Women only
- Adult
Study population: The study population comprises pregnant individuals with pre-pregnancy obesity (BMI ≥ 30.0 kg/m²) who had a singleton live birth in the United States in 2024, as recorded in the NVSS Natality Public Use File. Eligible participants initiated prenatal care in the first trimester, delivered between 24 and 41 completed weeks of gestation, and were aged 18-45 years at delivery. The cohort is stratified into three pre-pregnancy obesity classes: Class I (BMI 30.0-34.9 kg/m²), Class II (BMI 35.0-39.9 kg/m²), and Class III (BMI ≥ 40.0 kg/m²). Individuals with pre-existing diabetes or chronic hypertension, missing core outcome data, major congenital anomalies, or implausible GWG values are excluded. A separate 9-year (2016-2024) uncomplicated pregnancy reference cohort from the same NVSS database is used exclusively to derive race- and gestational-age-specific physiological GWG Z-scores; it is not part of the primary target trial emulation cohort.
Who may be able to join
- Singleton live births recorded in the U.S. National Vital Statistics System (NVSS) Natality database (2024 cohort for primary target trial emulation).
- Gestational age at delivery between 24 and 41 completed weeks (obstetric estimate).
- Maternal age between 18 and 45 years at delivery.
- Pre-pregnancy obesity defined as BMI ≥ 30.0 kg/m² (excluding unknown code 99.9).
- Early prenatal care initiated in the first trimester (Months 1-3; PRECARE5 recode = 1).
- Maternal race and ethnicity categorized as Non-Hispanic White, Non-Hispanic Black, Non-Hispanic Asian, or Hispanic.
Who cannot join
- Pre-existing (pre-pregnancy) diabetes mellitus or pre-existing chronic hypertension (confirmed or unknown status).
- Missing or unknown data on core maternal or neonatal outcomes (gestational diabetes, gestational hypertension, eclampsia, or infant birthweight).
- Any confirmed, suspected, or unknown congenital structural anomaly or chromosomal disorder (e.g., anencephaly, spina bifida, cyanotic congenital heart disease, congenital diaphragmatic hernia, omphalocele, gastroschisis, limb reduction defect, cleft lip/palate, Down syndrome, chromosomal disorder, or hypospadias).
- Biologically implausible or extreme gestational weight gain (GWG) values (< -10.0 kg or > +50.0 kg).
Trial locations and contacts
1 site in 1 country.
China1 site
Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine
Shanghai, Pudong New District, 201204
About this study
Official title: Gestational Weight Loss and Restrictive Weight Gain Across Maternal Obesity Classes: A Nationwide Target Trial Emulation in the United States
This study asks whether the current weight-gain guideline for pregnant people with obesity should be lowered, and whether the answer depends on how severe the obesity is. The guideline from the Institute of Medicine (IOM) recommends that all pregnant people with obesity gain 5.0 to 9.0 kg, regardless of obesity class. However, growing evidence suggests that people with Class II or III obesity may benefit from gaining less than this range-or even losing a small amount of weight-without harming the baby. A randomized trial to test this directly would be ethically and practically difficult, so this study uses a different approach: it reconstructs what such a trial would have shown, using nationwide U.S. birth records.
The study uses 2024 U.S. birth certificate data for people with pre-pregnancy obesity who had a single live birth. It compares three weight-gain patterns during pregnancy: (1) net weight loss (less than 0 kg gained), (2) restrictive gain (weight gained, but below the dynamic, gestational-age-specific IOM lower bound), and (3) standard gain within the IOM-recommended range. The main questions are whether restrictive gain or weight loss, compared with standard gain, reduces the risk of hypertensive disorders of pregnancy (such as gestational hypertension and preeclampsia) while not increasing the risk of a baby born small for gestational age (SGA). The study also examines whether the balance of benefits and harms differs across Class I, Class II, and Class III obesity.
This is an observational study, not a randomized trial. It does not enroll participants or provide treatment. All analyses use existing, de-identified public health data. Results are intended to inform whether future weight-gain guidelines should provide class-specific recommendations rather than a single range for all obesity classes.
Read the detailed description
Detailed Description
Background. The 2009 IOM guidelines recommend a uniform gestational weight gain (GWG) target of 5.0-9.0 kg for all pregnant people with obesity, without distinguishing between Class I (BMI 30.0-34.9 kg/m²), Class II (BMI 35.0-39.9 kg/m²), and Class III (BMI ≥ 40.0 kg/m²) obesity. This single-range approach is increasingly questioned because the cardiometabolic consequences of obesity are not uniform across severity strata. For individuals with Class II-III obesity, restrictive gain or modest gestational weight loss may reduce maternal hypertensive disorders of pregnancy (HDP) and normalize fetal overgrowth (large for gestational age, LGA), while maternal adipose reserves may protect against small-for-gestational-age (SGA) birth. A pragmatic randomized trial assigning pregnant people to gestational weight loss raises ethical and clinical equipoise concerns, and conventional observational analyses of GWG are vulnerable to gestational-age-related survival bias and baseline confounding.
Objectives. This study applies a formal target trial emulation framework to estimate the causal effect of three GWG strategies on a co-primary benefit-risk outcome pair: maternal HDP (efficacy) and fetal SGA (safety). A key secondary outcome is LGA. The central hypothesis is that the comparative benefit-risk profile of restrictive gain or weight loss versus standard IOM gain differs meaningfully across obesity classes, particularly in Class III obesity.
Design and data source. This is a retrospective, nationwide target trial emulation using the U.S. National Vital Statistics System (NVSS) Natality Public Use Files. The primary emulation cohort is drawn from the 2024 singleton live-birth cohort. A 10-year physiological reference cohort (2015-2024), restricted to uncomplicated pregnancies, is used to standardize GWG into race- and gestational-age-specific Z-scores.
Emulated strategies. To eliminate gestational-age-dependent survival bias, dynamic, gestational-age-specific IOM bounds are calculated for each delivery week from 24 to 41 weeks: a first-trimester gain of 1.1 kg plus a second/third-trimester velocity of 0.17 kg/week (lower bound) to 0.27 kg/week (upper bound). Participants are assigned to one of three strategies: Gestational Weight Loss (net GWG < 0.0 kg); Restrictive Gain (GWG ≥ 0.0 kg but below the dynamic IOM lower bound); or Standard IOM Gain (GWG within the dynamic IOM range; reference group). Individuals exceeding the dynamic IOM upper bound are not included in the three-arm comparison, because the study is designed to ask whether guidelines should be lowered, not whether they should be exceeded.
Causal estimation. Within each obesity class, generalized propensity scores for the three strategies are estimated via multinomial logistic regression, conditioned on continuous pre-pregnancy BMI and prespecified sociodemographic and clinical confounders. Propensity score overlap weighting (targeting the average treatment effect in the overlap population, ATO) is used to achieve covariate balance while avoiding extreme weight variance. ATO-weighted modified Poisson regression with robust sandwich variance estimators is used to estimate relative risks and absolute risk differences for HDP, SGA, and LGA. Risk differences are translated into numbers needed to treat for HDP/LGA prevention and numbers needed to harm for SGA induction.
Secondary and sensitivity analyses. Prespecified effect modification is evaluated within the Class III stratum across parity, race/ethnicity, and maternal age, with ATO weights re-estimated de novo in each subgroup. A biological negative control outcome (infant male sex) is analyzed to detect residual structural confounding. Sensitivity analyses include alternative first-trimester gain assumptions (0.0 kg and 2.0 kg), E-value quantitative bias analysis for statistically significant causal estimates, and multiple imputation by chained equations to address missing data, alongside the primary complete-case analysis.
Reproducibility. Data extraction, physiological Z-score modeling, and cohort construction are performed in Python 3.9.6. Overlap weighting, modified Poisson regression, marginal effect extraction, and E-value calculation are performed in R (v4.5.1).
- Conditions
- Pregnancy, Obesity, Gestational Hypertension, Gestational Weight Gain
- Being tested
- Gestational Weight Gain (GWG) Strategy
- Keywords
- obesity, pregnancy, gestational hypertension, gestational weight gain
- Medical subject headings
- Obesity, Hypertension, Pregnancy-Induced, Gestational Weight Gain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Gestational Weight Gain (GWG) StrategyOther
The study exposure is the pattern of total gestational weight gain (GWG) during pregnancy, categorized into three mutually exclusive strategies based on dynamic, gestational-age-specific IOM thresholds: Gestational Weight Loss (GWG < 0 kg), Restrictive Weight Gain (GWG ≥ 0 kg but below the IOM lower bound), and Standard IOM Gain (GWG within the IOM recommended range).
| Study group | Role | What they receive |
|---|---|---|
| Gestational Weight Loss | Participants with net gestational weight gain (GWG) < 0.0 kg during pregnancy. Receives: Other: Gestational Weight Gain (GWG) Strategy | |
| Restrictive Weight Gain | Participants with net GWG ≥ 0.0 kg but strictly below the dynamic, gestational-age-specific IOM lower bound. Receives: Other: Gestational Weight Gain (GWG) Strategy | |
| Standard IOM Gain (Reference) | Participants with net GWG within the dynamic, gestational-age-specific IOM recommended range [Lower Bound, Upper Bound]. This is the reference group. Receives: Other: Gestational Weight Gain (GWG) Strategy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hypertensive Disorders of Pregnancy (HDP)
A composite binary endpoint of incident gestational hypertension or preeclampsia/eclampsia during pregnancy.
Measured: Up to delivery
Small for Gestational Age (SGA)
Neonatal birthweight <10th percentile for gestational age, stratified by infant sex and maternal parity using validated U.S. national birthweight reference tables.
Measured: At birth.
Secondary outcomes (1)
Large for Gestational Age (LGA)
Neonatal birthweight >90th percentile for gestational age, sex, and parity, evaluating the normalization of maternal obesity-driven fetal overgrowth.
Measured: At birth.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Oct 2026
- Study start1 Jan 2026
- Primary completion1 Oct 2026
- Study completion19 Oct 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for PregnancyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 205,636 participants (actual)
Sponsor and investigators
- Lead sponsor
- Shanghai First Maternal and Infant Health Hospital affiliated to Tongji University Medical School
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Xiaobo Zhao, Shanghai First Maternal and Infant Health Hospital affiliated to Tongji University Medical School
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07902232
- Sponsor's protocol ID
- 20261019
- Acronym
- GWG HDP
- Status last verified
- Oct 2026
- First submitted
- 18 Oct 2026
- Last updated
- 6 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data (IPD) will not be shared by the investigators because the source data are de-identified public-use files from the U.S. National Center for Health Statistics (NCHS), National Vital Statistics System (NVSS) Natality Public Use Files. These data are publicly available to all researchers through standard NCHS access procedures, and the investigators do not have authority to redistribute NVSS records. To promote transparency and reproducibility, the analytic code (including Python and R scripts for cohort construction, physiological GWG Z-score standardization, propensity score overlap weighting, modified Poisson regression, and sensitivity analyses), variable definitions, and data dictionary will be made available from the corresponding author upon reasonable request and will be deposited in a public repository upon publication. These materials will be shared with researchers for the purpose of replication, methodological verification, or secondary methodologica
Publications
Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines; Rasmussen KM, Yaktine AL, editors. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington (DC): National Academies Press (US); 2009. Available from http://www.ncbi.nlm.nih.gov/books/NBK32813/
PubMed 20669500Hutcheon JA, Platt RW, Abrams B, Himes KP, Simhan HN, Bodnar LM. Pregnancy weight gain charts for obese and overweight women. Obesity (Silver Spring). 2015 Mar;23(3):532-5. doi: 10.1002/oby.21011.
PubMed 25707378Kominiarek MA, Peaceman AM. Gestational weight gain. Am J Obstet Gynecol. 2017 Dec;217(6):642-651. doi: 10.1016/j.ajog.2017.05.040. Epub 2017 May 24.
PubMed 28549978Bodnar LM, Siega-Riz AM, Simhan HN, Himes KP, Abrams B. Severe obesity, gestational weight gain, and adverse birth outcomes. Am J Clin Nutr. 2010 Jun;91(6):1642-8. doi: 10.3945/ajcn.2009.29008. Epub 2010 Mar 31.
PubMed 20357043Poston L, Caleyachetty R, Cnattingius S, Corvalan C, Uauy R, Herring S, Gillman MW. Preconceptional and maternal obesity: epidemiology and health consequences. Lancet Diabetes Endocrinol. 2016 Dec;4(12):1025-1036. doi: 10.1016/S2213-8587(16)30217-0. Epub 2016 Oct 12.
PubMed 27743975
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Gestational Weight Loss and Restrictive Weight Gain Across Maternal Obesity Classes: A Nationwide Target Trial Emulation in the United States
- ClinicalTrials.gov ID
- NCT07902232
- Acronym / sponsor ID
- GWG HDP / 20261019
- Conditions
- Pregnancy, Obesity, Gestational Hypertension, Gestational Weight Gain
- Keywords
- obesity, pregnancy, gestational hypertension, gestational weight gain
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 205,636 participants (actual)
- Lead sponsor
- Shanghai First Maternal and Infant Health Hospital affiliated to Tongji University Medical SchoolUniversity, hospital or other
- Study start
- 1 Jan 2026 (actual)
- Primary completion
- 1 Oct 2026 (actual)
- Study completion
- 19 Oct 2026 (actual)
- First posted
- 28 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study asks whether the current weight-gain guideline for pregnant people with obesity should be lowered, and whether the answer depends on how severe the obesity is. The guideline from the Institute of Medicine (IOM) recommends that all pregnant people with obesity gain 5.0 to 9.0 kg, regardless of obesity class. However, growing evidence suggests that people with Class II or III obesity may benefit from gaining less than this range-or even losing a small amount of weight-without harming the baby. A randomized trial to test this directly would be ethically and practically difficult, so this study uses a different approach: it reconstructs what such a trial would have shown, using nationwide U.S. birth records.
The study uses 2024 U.S. birth certificate data for people with pre-pregnancy obesity who had a single live birth. It compares three weight-gain patterns during pregnancy: (1) net weight loss (less than 0 kg gained), (2) restrictive gain (weight gained, but below the dynamic, gestational-age-specific IOM lower bound), and (3) standard gain within the IOM-recommended range. The main questions are whether restrictive gain or weight loss, compared with standard gain, reduces the risk of hypertensive disorders of pregnancy (such as gestational hypertension and preeclampsia) while not increasing the risk of a baby born small for gestational age (SGA). The study also examines whether the balance of benefits and harms differs across Class I, Class II, and Class III obesity.
This is an observational study, not a randomized trial. It does not enroll participants or provide treatment. All analyses use existing, de-identified public health data. Results are intended to inform whether future weight-gain guidelines should provide class-specific recommendations rather than a single range for all obesity classes.
Detailed description
Detailed Description
Background. The 2009 IOM guidelines recommend a uniform gestational weight gain (GWG) target of 5.0-9.0 kg for all pregnant people with obesity, without distinguishing between Class I (BMI 30.0-34.9 kg/m²), Class II (BMI 35.0-39.9 kg/m²), and Class III (BMI ≥ 40.0 kg/m²) obesity. This single-range approach is increasingly questioned because the cardiometabolic consequences of obesity are not uniform across severity strata. For individuals with Class II-III obesity, restrictive gain or modest gestational weight loss may reduce maternal hypertensive disorders of pregnancy (HDP) and normalize fetal overgrowth (large for gestational age, LGA), while maternal adipose reserves may protect against small-for-gestational-age (SGA) birth. A pragmatic randomized trial assigning pregnant people to gestational weight loss raises ethical and clinical equipoise concerns, and conventional observational analyses of GWG are vulnerable to gestational-age-related survival bias and baseline confounding.
Objectives. This study applies a formal target trial emulation framework to estimate the causal effect of three GWG strategies on a co-primary benefit-risk outcome pair: maternal HDP (efficacy) and fetal SGA (safety). A key secondary outcome is LGA. The central hypothesis is that the comparative benefit-risk profile of restrictive gain or weight loss versus standard IOM gain differs meaningfully across obesity classes, particularly in Class III obesity.
Design and data source. This is a retrospective, nationwide target trial emulation using the U.S. National Vital Statistics System (NVSS) Natality Public Use Files. The primary emulation cohort is drawn from the 2024 singleton live-birth cohort. A 10-year physiological reference cohort (2015-2024), restricted to uncomplicated pregnancies, is used to standardize GWG into race- and gestational-age-specific Z-scores.
Emulated strategies. To eliminate gestational-age-dependent survival bias, dynamic, gestational-age-specific IOM bounds are calculated for each delivery week from 24 to 41 weeks: a first-trimester gain of 1.1 kg plus a second/third-trimester velocity of 0.17 kg/week (lower bound) to 0.27 kg/week (upper bound). Participants are assigned to one of three strategies: Gestational Weight Loss (net GWG < 0.0 kg); Restrictive Gain (GWG ≥ 0.0 kg but below the dynamic IOM lower bound); or Standard IOM Gain (GWG within the dynamic IOM range; reference group). Individuals exceeding the dynamic IOM upper bound are not included in the three-arm comparison, because the study is designed to ask whether guidelines should be lowered, not whether they should be exceeded.
Causal estimation. Within each obesity class, generalized propensity scores for the three strategies are estimated via multinomial logistic regression, conditioned on continuous pre-pregnancy BMI and prespecified sociodemographic and clinical confounders. Propensity score overlap weighting (targeting the average treatment effect in the overlap population, ATO) is used to achieve covariate balance while avoiding extreme weight variance. ATO-weighted modified Poisson regression with robust sandwich variance estimators is used to estimate relative risks and absolute risk differences for HDP, SGA, and LGA. Risk differences are translated into numbers needed to treat for HDP/LGA prevention and numbers needed to harm for SGA induction.
Secondary and sensitivity analyses. Prespecified effect modification is evaluated within the Class III stratum across parity, race/ethnicity, and maternal age, with ATO weights re-estimated de novo in each subgroup. A biological negative control outcome (infant male sex) is analyzed to detect residual structural confounding. Sensitivity analyses include alternative first-trimester gain assumptions (0.0 kg and 2.0 kg), E-value quantitative bias analysis for statistically significant causal estimates, and multiple imputation by chained equations to address missing data, alongside the primary complete-case analysis.
Reproducibility. Data extraction, physiological Z-score modeling, and cohort construction are performed in Python 3.9.6. Overlap weighting, modified Poisson regression, marginal effect extraction, and E-value calculation are performed in R (v4.5.1).
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Gestational Weight Loss | – | Other: Gestational Weight Gain (GWG) StrategyParticipants with net gestational weight gain (GWG) < 0.0 kg during pregnancy. |
| Restrictive Weight Gain | – | Other: Gestational Weight Gain (GWG) StrategyParticipants with net GWG ≥ 0.0 kg but strictly below the dynamic, gestational-age-specific IOM lower bound. |
| Standard IOM Gain (Reference) | – | Other: Gestational Weight Gain (GWG) StrategyParticipants with net GWG within the dynamic, gestational-age-specific IOM recommended range [Lower Bound, Upper Bound]. This is the reference group. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Female only
- Age groups
- Adult
- Study population
- The study population comprises pregnant individuals with pre-pregnancy obesity (BMI ≥ 30.0 kg/m²) who had a singleton live birth in the United States in 2024, as recorded in the NVSS Natality Public Use File. Eligible participants initiated prenatal care in the first trimester, delivered between 24 and 41 completed weeks of gestation, and were aged 18-45 years at delivery. The cohort is stratified into three pre-pregnancy obesity classes: Class I (BMI 30.0-34.9 kg/m²), Class II (BMI 35.0-39.9 kg/m²), and Class III (BMI ≥ 40.0 kg/m²). Individuals with pre-existing diabetes or chronic hypertension, missing core outcome data, major congenital anomalies, or implausible GWG values are excluded. A separate 9-year (2016-2024) uncomplicated pregnancy reference cohort from the same NVSS database is used exclusively to derive race- and gestational-age-specific physiological GWG Z-scores; it is not part of the primary target trial emulation cohort.
Key inclusion criteria (6 listed)
- Singleton live births recorded in the U.S. National Vital Statistics System (NVSS) Natality database (2024 cohort for primary target trial emulation).
- Gestational age at delivery between 24 and 41 completed weeks (obstetric estimate).
- Maternal age between 18 and 45 years at delivery.
- Pre-pregnancy obesity defined as BMI ≥ 30.0 kg/m² (excluding unknown code 99.9).
- Early prenatal care initiated in the first trimester (Months 1-3; PRECARE5 recode = 1).
Key exclusion criteria (4 listed)
- Pre-existing (pre-pregnancy) diabetes mellitus or pre-existing chronic hypertension (confirmed or unknown status).
- Missing or unknown data on core maternal or neonatal outcomes (gestational diabetes, gestational hypertension, eclampsia, or infant birthweight).
- Any confirmed, suspected, or unknown congenital structural anomaly or chromosomal disorder (e.g., anencephaly, spina bifida, cyanotic congenital heart disease, congenital diaphragmatic hernia, omphalocele, gastroschisis, limb reduction defect, cleft lip/palate, Down syndrome, chromosomal disorder, or hypospadias).
- Biologically implausible or extreme gestational weight gain (GWG) values (< -10.0 kg or > +50.0 kg).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Gestational Weight Gain (GWG) StrategyThe study exposure is the pattern of total gestational weight gain (GWG) during pregnancy, categorized into three mutually exclusive strategies based on dynamic, gestational-age-specific IOM thresholds: Gestational Weight Loss (GWG < 0 kg), Restrictive Weight Gain (GWG ≥ 0 kg but below the IOM lower bound), and Standard IOM Gain (GWG within the IOM recommended range). | Other | Gestational Weight Loss, Restrictive Weight Gain, Standard IOM Gain (Reference) |
Primary outcome
Hypertensive Disorders of Pregnancy (HDP)
Time frame: Up to delivery
A composite binary endpoint of incident gestational hypertension or preeclampsia/eclampsia during pregnancy.
Small for Gestational Age (SGA)
Time frame: At birth.
Neonatal birthweight <10th percentile for gestational age, stratified by infant sex and maternal parity using validated U.S. national birthweight reference tables.
1 secondary outcome
Large for Gestational Age (LGA)
Time frame: At birth.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2026.
- Results publication: PubMed 20669500Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines; Rasmussen KM, Yaktine AL, editors. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington (DC): National Academies Press (US); 2009. Available from http://www.ncbi.nlm.nih.gov/books/NBK32813/
- Results publication: PubMed 25707378Hutcheon JA, Platt RW, Abrams B, Himes KP, Simhan HN, Bodnar LM. Pregnancy weight gain charts for obese and overweight women. Obesity (Silver Spring). 2015 Mar;23(3):532-5. doi: 10.1002/oby.21011.
- Results publication: PubMed 28549978Kominiarek MA, Peaceman AM. Gestational weight gain. Am J Obstet Gynecol. 2017 Dec;217(6):642-651. doi: 10.1016/j.ajog.2017.05.040. Epub 2017 May 24.
- Results publication: PubMed 20357043Bodnar LM, Siega-Riz AM, Simhan HN, Himes KP, Abrams B. Severe obesity, gestational weight gain, and adverse birth outcomes. Am J Clin Nutr. 2010 Jun;91(6):1642-8. doi: 10.3945/ajcn.2009.29008. Epub 2010 Mar 31.
- Results publication: PubMed 27743975Poston L, Caleyachetty R, Cnattingius S, Corvalan C, Uauy R, Herring S, Gillman MW. Preconceptional and maternal obesity: epidemiology and health consequences. Lancet Diabetes Endocrinol. 2016 Dec;4(12):1025-1036. doi: 10.1016/S2213-8587(16)30217-0. Epub 2016 Oct 12.
- Individual participant dataSharing planned: No. Individual participant data (IPD) will not be shared by the investigators because the source data are de-identified public-use files from the U.S. National Center for Health Statistics (NCHS), National Vital Statistics System (NVSS) Natality Public Use Files. These data are publicly available to all researchers through standard NCHS access procedures, and the investigators do not have authority to redistribute NVSS records. To promote transparency and reproducibility, the analytic code (including Python and R scripts for cohort construction, physiological GWG Z-score standardization, propensity score overlap weighting, modified Poisson regression, and sensitivity analyses), variable definitions, and data dictionary will be made available from the corresponding author upon reasonable request and will be deposited in a public repository upon publication. These materials will be shared with researchers for the purpose of replication, methodological verification, or secondary methodologica
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Pregnancy and Obesity, run by Shanghai First Maternal and Infant Health Hospital affiliated to Tongji University Medical School at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hypertensive Disorders of Pregnancy (HDP) (time frame: Up to delivery). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07902232, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2026.