Yuquan Wu

Longitudinal vitamin D status in pregnancy and the risk of pre-eclampsia

Please cite this paper as: Dr Wei SQ, Audibert F, Hidiroglou N, Sarafin K, Julien P, Wu Y, Luo ZC, Fraser WD. Longitudinal vitamin D status in pregnancy and the risk of pre‐eclampsia. BJOG 2012;119:832–839.

Maternal and Fetal IGF-I and IGF-II Levels, Fetal Growth, and Gestational Diabetes

CONTEXT It remains uncertain whether maternal IGF-I is associated with fetal growth. Little is known about the role of maternal IGF-II in fetal growth and whether IGF-I or IGF-II is implicated in fetal hypertrophy in gestational diabetes. OBJECTIVE The objective of the study was to assess maternal and fetal IGF-I and IGF-II levels in association with fetal growth and gestational diabetes. STUDY DESIGN, POPULATION, AND OUTCOMES: A singleton pregnancy cohort study (n = 307). The primary outcome was birth weight. RESULTS Maternal plasma concentrations increased by an average of 55.4% for IGF-I and 11.8% for IGF-II between 24-28 and 32-35 weeks of gestation. The maternal IGF-I but not IGF-II level was correlated with birth weight and placental weight. Adjusting for maternal and infant characteristics, each SD increase in maternal IGF-I level at 24-28 weeks was associated with a 75-g (95% confidence intervals 29-120) increase in birth weight, a 20-g (7-33) increase in placental weight, and a 1.91-fold (1.28-2.86) higher odds of macrosomia (birth weight > 90th percentile). Similar associations were observed for the maternal IGF-I level at 32-35 weeks. Maternal and fetal IGF-I (but not IGF-II) levels were significantly higher in gestational diabetic than in nondiabetic pregnancies. The significantly higher birth weight z scores in diabetic pregnancies disappeared after adjusting for maternal and fetal IGF-I levels alone. CONCLUSIONS Higher maternal IGF-I (but not IGF-II) levels at mid- and late gestation may indicate greater placental and fetal growth. IGF-I (but not IGF-II) may be implicated in fetal hypertrophy in gestational diabetes.

Association of uric acid with progression to preeclampsia and development of adverse conditions in gestational hypertensive pregnancies

BACKGROUND Preeclampsia is a serious pregnancy complication. Gestational hypertension is a common first clinical presentation of preeclampsia. Little is known about which clinical risk factors are associated with the progression from gestational hypertension to preeclampsia. METHODS In a retrospective cohort study of 249 singleton pregnant women with an initial presentation of gestational hypertension in an obstetric hospital, we assessed which routinely available clinical risk factors are associated with the progression to preeclampsia and the development of adverse maternal or infant conditions. RESULTS The mean serum uric acid level at the initial presentation of gestational hypertension was significantly higher comparing patients who later progressed to preeclampsia to those who did not (5.06 vs. 4.59 mg/dl, P < 0.01). Lower gestational age and higher serum uric acid level at the initial presentation of gestational hypertension and subsequent need for antihypertensive drug treatment for blood pressure (BP) control were associated with significantly increased risks of progression to preeclampsia, and development of adverse maternal or infant conditions. One standard deviation (s.d.) increase in serum uric acid level was associated with 2.3-fold increased odds of progression to preeclampsia (adjusted odds ratio (aORs) 2.33 (95% confidence interval (CI) 1.45-3.74)), and 1.5-fold increased odds of developing clinically significant adverse maternal or infant conditions (aOR 1.49 (1.03-2.17)) irrespective of the progression to preeclampsia. CONCLUSIONS Higher serum uric acid levels at the initial presentation of gestational hypertension may indicate heightened risk of progression to preeclampsia and development of adverse maternal/infant conditions.

Primary birthing attendants and birth outcomes in remote Inuit communities - a natural "experiment" in Nunavik, Canada

Background: There is a lack of data on the safety of midwife-led maternity care in remote or indigenous communities. In a de facto natural “experiment”, birth outcomes were assessed by primary birthing attendant in two sets of remote Inuit communities. Methods: A geocoding-based retrospective birth cohort study in 14 Inuit communities of Nunavik, Canada, 1989–2000: primary birth attendants were Inuit midwives in the Hudson Bay (1529 Inuit births) vs western physicians in Ungava Bay communities (1197 Inuit births). The primary outcome was perinatal death. Secondary outcomes included stillbirth, neonatal death, post-neonatal death, preterm, small-for-gestational-age and low birthweight birth. Multilevel logistic regression was used to obtain the adjusted odds ratios (aOR) controlling for maternal age, marital status, parity, education, infant sex and plurality, community size and community-level random effects. Results: The aORs (95% confidence interval) for perinatal death comparing the Hudson Bay vs Ungava Bay communities were 1.29 (0.63 to 2.64) for all Inuit births and 1.13 (0.48 to 2.47) for Inuit births at ⩾28 weeks of gestation. There were no statistically significant differences in the crude or adjusted risks of any of the outcomes examined. Conclusion: Risks of perinatal death were somewhat but not significantly higher in the Hudson Bay communities with midwife-led maternity care compared with the Ungava Bay communities with physician-led maternity care. These findings are inconclusive, although the results excluding extremely preterm births are more reassuring concerning the safety of midwife-led maternity care in remote indigenous communities.

Neighborhood Socioeconomic Characteristics, Birth Outcomes and Infant Mortality among First Nations and Non-First Nations in Manitoba, Canada

Objective Little is known about the possible impacts of neighborhood socioeconomic status on birth outcomes and infant mortality among Aboriginal populations. We assessed birth outcomes and infant mortality by neighborhood socioeconomic status among First Nations and non-First Nations in Manitoba. Study Design We conducted a retrospective birth cohort study of all live births (26,176 First Nations, 129,623 non-First Nations) to Manitoba residents, 1991–2000. Maternal residential postal codes were used to assign four measures of neighborhood socioeconomic status (concerning income, education, unemployment, and lone parenthood) obtained from 1996 census data. Results First Nations women were much more likely to live in neighborhoods of low socioeconomic status. First Nations infants were much more likely to die during their first year of life [risk ratio (RR) =1.9] especially during the postneonatal period (RR=3.6). For both First Nations and non-First Nations, living in neighborhoods of low socioeconomic status was associated with an increased risk of infant death, especially postneonatal death. For non-First Nations, higher rates of pre-term and small-for-gestational-age birth were consistently observed in low socioeconomic status neighborhoods, but for First Nations the associations were less consistent across the four measures of socioeconomic status. Adjusting for neighborhood socioeconomic status, the disparities in infant and postneonatal mortality between First Nations and non-First Nations were attenuated. Conclusion Low neighborhood socioeconomic status was associated with an elevated risk of infant death even among First Nations, and may partly account for their higher rates of infant mortality compared to non-First Nations in Manitoba.

OC22.01: Prediction of small‐for‐gestational age neonates by third trimester fetal biometry: impact of ultrasound‐delivery interval

To compare third‐trimester ultrasound screening methods to predict small‐for‐gestational age (SGA), and to evaluate the impact of the ultrasound–delivery interval on screening performance.

North-South Gradients in Adverse Birth Outcomes for First Nations and Others in Manitoba, Canada

Objective to determine the relationship of north-south place of residence to adverse birth outcomes among First Nations and non-First Nations in Manitoba, Canada, a setting with universal health insurance. Study Design Live birth records (n=151,472) for the province of Manitoba, Canada 1991–2000 were analyzed, including 25,743 First Nations and 125,729 non-First Nations infants. North-south and rural-urban residence was determined for each birth through geocoding. Results Comparing First Nations to non-First Nations, crude rates in North (and South) were: 7.0% versus 8.4% (9.3% versus 7.5%) for preterm birth; 6.1% versus 8.4% (8.7% versus 10.0%) for small-for-gestational-age birth, 4.2% versus 6.5% (6.2% versus 5.7%) for low birth weight, and 20.6% versus 13.7% (17.0% versus 11.0%) for large-for-gestational-age birth; and mortality per 1000 - neonatal 3.2 versus 6.2 (3.8 versus 3.3), post-neonatal 6.4 versus 6.4 (5.8 versus 1.5), and infant 9.5 versus 12.6 (9.6 versus 4.8). Adjusting for observed maternal and infant characteristics and rural versus urban residence, the North was high risk for large-for-gestational-age birth for both First Nations and non-First Nations. First Nations’ risk of preterm, small-for-gestational-age and low birth weight was lowest in the North, but for non-First Nations, the North was lower only for small-for-gestational-age. First Nations mortality indicators were similar North to South, but for non-First Nations, the North was high risk. Conclusion North-South place of residence does matter for adverse birth outcomes, but the effects may differ by ethnicity and could require different intervention strategies.