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

Association of duration of embryo culture with risk of large for gestational age delivery in cryopreserved embryo transfer cycles

OBJECTIVE

To examine the relationship between the day of embryo cryopreservation and large for gestational age (LGA) infants in women undergoing frozen embryo transfers (FETs) after cryopreservation on days 2-7 after fertilization and to compare the risk of the day of embryo cryopreservation to other possible risk factors of LGA after FET cycles.

DESIGN

Retrospective cohort study.

SETTING

Society of Assisted Reproduction Clinical Outcomes Reporting System.

PATIENTS

Women undergoing FET cycles.

INTERVENTION

Day of cryopreservation.

MAIN OUTCOME MEASURE

Singleton LGA infant.

RESULTS

A total of 33,030 (18.2%) FET cycles in the study group (n = 181,592) resulted in LGA infants during the study period of 2014-2019. There was an increase in LGA risk when cryopreservation was performed from day 2 (13.7%) to days 3-7 (14.4%, 15.0%, 18.2%, 18.5%, and 18.9%). In the log-binomial model, the risk increased compared with days 2-3 combined when cryopreservation was performed on days 5-7 (adjusted relative risk [aRR] 1.32, 95% confidence interval [CI] 1.22-1.44 for day 5, aRR 1.34, 95% CI 1.23-1.46 for day 6, and aRR 1.42, 95% CI 1.25-1.61 for day 7). Other factors most associated with LGA risk in the log-binomial model were preterm parity of >3 compared with 0 (aRR 1.82, 95% CI 1.24-2.69) and body mass index (BMI) of >35 kg/m2 compared with normal weight (aRR 1.94, 95% CI 1.88-2.01). Increasing gravity, parity, BMI, number of oocytes, and embryo grade were also associated with LGA in this model. Asian, Black, Hispanic, and combined Hawaiian and Pacific Islander were protective factors in the model compared with White patients. Low BMI (<18.5 kg/m2) was also considered a protective factor in the model compared with normal BMI.

CONCLUSION

Duration of embryo culture was associated with an increased risk of LGA in this study cohort when controlling for known confounders such as maternal BMI and parity. This study sheds new light on the possible link between FET and LGA infants.

Racial variations of adverse perinatal outcomes: A population-based retrospective cohort study in Ontario, Canada

Introduction

Racial differences in adverse maternal and birth outcomes have been studied in other countries, however, there are few studies specific to the Canadian population. In this study, we sought to examine the inequities in adverse perinatal outcomes between Black and White pregnant people in Ontario, Canada.

Methods

We conducted a population-based retrospective cohort study that included all Black and White pregnant people who attended prenatal screening and had a singleton birth in any Ontario hospital (April 1^st, 2012-March 31^st, 2019). Poisson regression with robust error variance models were used to estimate the adjusted relative risks of adverse perinatal outcomes for Black people compared with White people while adjusting for covariates.

Results

Among 412,120 eligible pregnant people, 10.1% were Black people and 89.9% were White people. Black people were at an increased risk of gestational diabetes mellitus, preeclampsia, placental abruption, preterm birth (<37, <34, <32 weeks), spontaneous preterm birth, all caesarean sections, emergency caesarean section, low birth weight (<2500g, <1500g), small-for-gestational-age (<10th percentile, <3^rd percentile) neonates, 5-minute Apgar score <4 and <7, neonatal intensive care unit admission, and hyperbilirubinemia requiring treatment but had lower risks of elective caesarean section, assisted vaginal delivery, episiotomy, 3rd and 4th degree perineal tears, macrosomia, large-for-gestational-age neonates, and arterial cord pH≤7.1, as compared with White people. No difference in risks of gestational hypertension and placenta previa were observed between Black and White people.

Conclusion

There are differences in several adverse perinatal outcomes between Black and White people within the Ontario health care system. Findings might have potential clinical and health policy implications, although more studies are needed to further understand the mechanisms.

Caucasian and Asian difference in role of type 1 diabetes on large-for-gestational-age neonates

INTRODUCTION

Racial differences in the association between type 1 diabetes mellitus (T1DM) and large-for-gestational-age (LGA) neonates remain unclear. The objective of this study was to compare the effect of T1DM on LGA neonates between Caucasian and Asian women.

RESEARCH DESIGN AND METHODS

A population-based retrospective cohort study was conducted among Caucasian and Asian women who had prenatal screening and gave a singleton live birth in an Ontario hospital between April 2015 and March 2018. Multivariable log-binomial regression models were used to estimate the adjusted relative risks (aRRs) and 95% CIs of T1DM on LGA for Caucasian and Asian women. Relative contribution of T1DM to LGA was examined by multivariable logistic regression model, stratified by Caucasian and Asian women.

RESULTS

A total of 232 503 women (69.4% Caucasians and 30.6% Asians) were included in the final analysis. The rate of T1DM was higher in Caucasians (0.5%) than in Asians (0.2%), and the rate of LGA neonates was also higher in Caucasians (11.0%) than in Asians (5.0%). The association between T1DM and LGA in Caucasians (aRR 4.18, 95% CI (3.84 to 4.55)) was more robust than that in Asians (aRR 2.11, 95% CI (1.24 to 3.59)). T1DM was the fourth strongest contributor to LGA in Caucasians, while T1DM was the seventh contributor to LGA in Asians.

CONCLUSIONS

T1DM plays a more substantial role in LGA among Caucasians than Asians. Clinicians should be aware of the Caucasian-Asian differences of effects of T1DM on LGA when developing pregnancy management strategies.