Fetal growth between the first and second trimesters and the risk of adverse pregnancy outcome

Analyzing the impact of phthalate and DINCH exposure on fetal growth in a cohort with repeated urine collection

BACKGROUND

Most previous studies investigating the associations between prenatal exposure to phthalates and fetal growth relied on measurements of phthalate metabolites at a single time point. They also focused on weight at birth without assessing growth over pregnancy, preventing the identification of potential periods of fetal vulnerability. We examined the associations between pregnancy urinary phthalate metabolites and fetal growth outcomes measured twice during pregnancy and at birth.

METHODS

For 484 pregnant women, we assessed 13 phthalate and two 1,2-cyclohexane dicarboxylic acid, diisononyl ester (DINCH) metabolite concentrations from two within-subject weekly pools of up to 21 urine samples (median of 18 and 34 gestational weeks, respectively). Fetal biparietal diameter, femur length, head and abdominal circumferences were measured during two routine pregnancy follow-up ultrasonographies (median 22 and 32 gestational weeks, respectively) and estimated fetal weight (EFW) was calculated. Newborn weight, length, and head circumference were measured at birth. Associations between phthalate/DINCH metabolite and growth parameters were investigated using adjusted linear regression and Bayesian kernel machine regression models.

RESULTS

Detection rates were above 99 % for all phthalate/DINCH metabolites. While no association was observed with birth measurements, mono-iso-butyl phthalate (MiBP) and mono-n-butyl phthalate (MnBP) were positively associated with most fetal growth parameters measured at the second trimester. Specifically, MiBP was positively associated with biparietal diameter, head and abdominal circumferences, while MnBP was positively associated with EFW, head and abdominal circumferences, with stronger associations among males. Pregnancy MnBP was positively associated with biparietal diameter and femur length at third trimester. Mixture of phthalate/DINCH metabolites was positively associated with EFW at second trimester.

CONCLUSIONS

In this pregnancy cohort using repeated urine samples to assess exposure, MiBP and MnBP were associated with increased fetal growth parameters. Further investigation on the effects of phthalates on child health would be relevant for expanding current knowledge on their long-term effects.

Does decreased fetal growth estimation in the appropriate for gestational age range affect delivery outcomes?

PURPOSE

To study the effect of decreased estimated fetal weight (EFW) percentiles in appropriate for gestational age fetuses.

METHODS

This retrospective cohort study included women who had second and third trimester ultrasound examinations. Delivery and neonatal outcomes of pregnancies with decreased EFW of ≥  30 percentiles in EFW between ultrasound examinations (decreased growth group) and those without such a decrease (control group) were compared. Deliveries with EFW or birthweight below the 10th percentile were excluded.

RESULTS

Among 1610 deliveries, 57 were in the decreased growth group and 1553 in the control group. Maternal characteristics did not differ between the groups except for higher rate of nulliparity in the decreased growth group. We found similar rates of Category II/III monitoring, cesarean deliveries due to non-reassuring fetal heart rate and adverse neonatal outcomes. Neonatal birthweight was lower in the decreased growth group as compared to controls.

CONCLUSIONS

This study did not find association between the group of appropriate for gestational age fetuses with decreased growth, with adverse outcomes.

Fetal Growth and Adiposity of Infants Born Large for Gestational Age in Three Harmonized Randomized Trials

OBJECTIVE

 Infants born large for gestational age (LGA) are at an increased risk of short- and longer-term adverse outcomes. Understanding fetal growth and adiposity and their trajectories may help inform interventions to prevent birth of LGA infants. We aimed to compare fetal growth and adiposity measures of infants born LGA with those born not LGA, to determine whether the discrepancy at birth was primarily due to larger size throughout gestation, or instead to different trajectories of fetal growth.

STUDY DESIGN

 This was a secondary analysis of secondary outcomes of fetal growth and adiposity from three harmonized randomized trials-the LIMIT, GRoW, and Optimise randomized trials. These trials recruited women in early pregnancy, and a singleton gestation, from three major public metropolitan Adelaide maternity hospitals. Maternal body mass index (BMI) ranged from 18.5 to ≥40.0 kg/m2. Data were obtained from enrolled women who underwent research ultrasounds at 28 and 36 weeks' gestation. Outcome measures were ultrasound measures of fetal biometry and adiposity.

RESULTS

 Infants born LGA had larger fetal biometry measures, and higher growth trajectories, from 20 weeks' gestation. Fetal adiposity measures were consistently larger among infants born LGA and these differences increased over time. We did not find evidence that the differences in biometry and adiposity measurements varied according to maternal BMI.

CONCLUSION

 Infants born LGA had larger fetal biometry measures at all time points from 20 weeks' gestation, compared with infants born not LGA suggesting any interventions to prevent LGA likely need to commence earlier in pregnancy or prior to conception.

KEY POINTS

· Infants born LGA had larger fetal biometry measures from 20 weeks' gestation.. · Infants born LGA had larger fetal adiposity measures.. · Interventions to prevent LGA need to start earlier in pregnancy or prior to conception..

microRNA signatures associated with fetal growth restriction: a systematic review

Placental-origin microRNA (miRNA) profiles can be useful toward early diagnosis and management of fetal growth restriction (FGR) and associated complications. We conducted a systematic review to identify case-control studies that have examined miRNA signatures associated with human FGR. We systematically searched PubMed and ScienceDirect databases for relevant articles and manually searched reference lists of the relevant articles till May 18th, 2021. Of the 2133 studies identified, 21 were included. FGR-associated upregulation of miR-210 and miR-424 and downregulation of a placenta-specific miRNA cluster miRNA located on C19MC (miR-518b, miR-519d) and miR-221-3p was reported by >1 included studies. Analysis of the target genes of these miRNA as well as pathway analysis pointed to the involvement of angiogenesis and growth signaling pathways, such as the phosphatidylinositol 3-kinase- protein kinase B (PI3K-Akt) pathway. Only 3 out of the 21 included studies reported FGR-associated miRNAs in matched placental and maternal blood samples. We conclude that FGR-associated placental miRNAs could be utilized to inform clinical practice towards early diagnosis of FGR, provided enough evidence from studies on matched placental and maternal blood samples become available.Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD42019136762.

Reduced fetal growth velocity precedes antepartum fetal death

OBJECTIVES

To determine whether decreased fetal growth velocity precedes antepartum fetal death and to evaluate whether fetal growth velocity is a better predictor of antepartum fetal death compared to a single fetal biometric measurement at the last available ultrasound scan prior to diagnosis of demise.

METHODS

This was a retrospective, longitudinal study of 4285 singleton pregnancies in African-American women who underwent at least two fetal ultrasound examinations between 14 and 32 weeks of gestation and delivered a liveborn neonate (controls; n = 4262) or experienced antepartum fetal death (cases; n = 23). Fetal death was defined as death diagnosed at ≥ 20 weeks of gestation and confirmed by ultrasound examination. Exclusion criteria included congenital anomaly, birth at < 20 weeks of gestation, multiple gestation and intrapartum fetal death. The ultrasound examination performed at the time of fetal demise was not included in the analysis. Percentiles for estimated fetal weight (EFW) and individual biometric parameters were determined according to the Hadlock and Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (PRB/NICHD) fetal growth standards. Fetal growth velocity was defined as the slope of the regression line of the measurement percentiles as a function of gestational age based on two or more measurements in each pregnancy.

RESULTS

Cases had significantly lower growth velocities of EFW (P < 0.001) and of fetal head circumference, biparietal diameter, abdominal circumference and femur length (all P < 0.05) compared to controls, according to the PRB/NICHD and Hadlock growth standards. Fetuses with EFW growth velocity < 10^th percentile of the controls had a 9.4-fold and an 11.2-fold increased risk of antepartum death, based on the Hadlock and customized PRB/NICHD standards, respectively. At a 10% false-positive rate, the sensitivity of EFW growth velocity for predicting antepartum fetal death was 56.5%, compared to 26.1% for a single EFW percentile evaluation at the last available ultrasound examination, according to the customized PRB/NICHD standard.

CONCLUSIONS

Given that 74% of antepartum fetal death cases were not diagnosed as small-for-gestational age (EFW < 10^th percentile) at the last ultrasound examination when the fetuses were alive, alternative approaches are needed to improve detection of fetuses at risk of fetal death. Longitudinal sonographic evaluation to determine growth velocity doubles the sensitivity for prediction of antepartum fetal death compared to a single EFW measurement at the last available ultrasound examination, yet the performance is still suboptimal. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Accelerated fetal growth in early pregnancy and risk of preterm birth: a prospective cohort study

BACKGROUND

Preterm birth (occurring before 37 completed weeks of gestation) affects 15 million infants annually, 7.5% of which die due to related complications. The detection and early diagnosis are therefore paramount in order to prevent the development of prematurity and its consequences. So far, focus has been laid on the association between reduced intrauterine fetal growth during late gestation and prematurity. The aim of the current study was to investigate the association between accelerated fetal growth in early pregnancy and the risk of preterm birth.

METHODS

This prospective cohort study included 69,617 singleton pregnancies without congenital malformations and with available biometric measurements during the first and second trimester. Estimation of fetal growth was based on measurements of biparietal diameter (BPD) at first and second trimester scan. We investigated the association between accelerated fetal growth and preterm birth prior to 37 weeks of gestation. The outcome was further stratified into very preterm birth (before 32 weeks of gestation) or moderate preterm birth (between 32 and 37 weeks of gestation) and medically induced or spontaneous preterm birth and was further explored.

RESULTS

The odds of prematurity were increased among fetuses with accelerated BPD growth (> 90th centile) estimated between first and second ultrasound scan, even after adjustment for possible confounders (aOR 1.36; 95% CI 1.20-1.54). The findings remained significant what regards moderate preterm births but not very preterm births. Regarding medically induced preterm birth, the odds were found to be elevated in the group of fetuses with accelerated growth in early pregnancy (aOR 1.34; 95% CI 1.11-1.63). On the contrary, fetuses with delayed fetal growth exhibited lower odds for both overall and spontaneous preterm birth.

CONCLUSIONS

Fetuses with accelerated BPD growth in early pregnancy, detected by ultrasound examination during the second trimester, exhibited increased odds of being born preterm. The findings of the current study suggest that fetal growth in early pregnancy should be taken into account when assessing the risk for preterm birth.

Second-trimester fetal head circumference in more than 350 000 pregnancies: Outcome and suggestion for sex-dependent cutoffs for small heads

OBJECTIVE

To explore the relationship between small fetal second-trimester head circumference (HC) and pregnancy outcome and identify a cutoff point for offering genetic testing.

METHOD

Data from second-trimester scans in Denmark were linked to national registers. Fetuses with anomalies diagnosed before this scan were excluded. Fetuses were grouped according to HC z-score.

RESULTS

We included 352 515 singleton fetuses. The mean HC was significantly larger among males than among females with z-scores averaging 0.52 more in males. Small HC was associated with chromosomal anomaly, malformations of the CNS and heart, miscarriage/perinatal death, termination, preterm delivery, and intrauterine growth restriction (test for trend: P < .001 for all outcomes). Fetuses in the group with z-score less than -3 had the highest incidence of adverse outcome, irrespective of fetal sex. In the groups with z-scores between -3 and -2.5, and between -2.5 and -2, risk of adverse outcome was lower for females than males for all outcome categories.

CONCLUSION

Small HC in second trimester is a prognostic marker for adverse outcome. The smaller the HC, the higher the risk of adverse outcome. We suggest an HC cutoff point of -2 SD for males and -2.5 SD for females for offering genetic testing.

Information bias in epidemiological studies with a special focus on obstetrics and gynecology

Information bias occurs when any information used in a study is either measured or recorded inaccurately. This paper describes some of the most common types of information bias, using examples from obstetrics and gynecology, and describes how information bias may affect results of observational studies. Non-differential misclassification occurs when the degree of misclassification of exposure status among those with and those without the disease is the same; in cohort studies, this type of bias is most likely and will bias estimates toward no association when exposure is dichotomized. Non-differential underreporting of an exposure with more than two categories may mask a true threshold effect as a dose-response relation and, if a true threshold effect exists, the threshold will be set at too low a level, if the exposure is underreported. Differential misclassification may cause bias in either direction and is particularly likely, when exposure status is reported after the outcome occurred. Misclassification of confounders is an issue that needs special attention by researchers, as failure to measure accurately one or more (strong) confounders may seriously bias the observed results. Misclassification of disease status may also cause bias of estimates of association in either direction. Information bias is probably best prevented during planning of data collection, as there are few and insufficient methods available for correcting inaccurate information.

Correlation Between Third Trimester Glycemic Variability in Non-Insulin-Dependent Gestational Diabetes Mellitus and Adverse Pregnancy and Fetal Outcomes

BACKGROUND

Gestational diabetes mellitus (GDM) is a pregnancy-related metabolic complication. Despite optimal glycemic control from self-monitoring blood glucose (SMBG) in non-insulin-dependent GDM, variations in pregnancy outcomes persist. Glycemic variability is believed to be a factor that causes adverse pregnancy outcomes. Continuous glucose monitoring system (CGMS) detects interstitial glucose values every 5 minutes, and glycemic variability data from CGMS during the third trimester may be a predictor of fetal birth weight and pregnancy outcomes. The aim of this study was to investigate correlation between third trimester glycemic variability in non-insulin-dependent GDM and fetal birth weight.

METHOD

This prospective study was conducted in 55 pregnant volunteers with non-insulin-dependent GDM that were recruited at 28 to 32 weeks' gestation from the outpatient clinic of the Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital during the study period of August 1 to December 31, 2016. Patients had CGMS installed for at least 72 hours and glycemic variability data were analyzed.

RESULTS

Of 55 enrolled volunteers, the data from 47 women were included in the analysis. Mean CGMS duration was 85.5 ± 12.83 hours. No statistically significant correlation was identified between glycemic variability in third trimester and birth weight percentiles, or between third trimester CGMS parameters and pregnancy outcomes in the study.

CONCLUSION

Based on these findings, third trimester glycemic variability data from CGMS are not a predictor of fetal birth weight percentile, and no significant association was found between CGMS parameters and adverse pregnancy outcomes; thus, CGMS is not necessary in non-insulin-dependent GDM.

Slow fetal growth between first and early second trimester ultrasound scans and risk of small for gestational age (SGA) birth

Objectives

To investigate the association between fetal growth between first and early second trimester ultrasound scan and the risk of severe small for gestational age (SGA) birth.

Methods

This cohort study included 69 550 singleton pregnancies with first trimester dating and an early second trimester growth scan in Stockholm and Gotland Counties, Sweden between 2008 and 2014. Exposure was difference in biparietal diameter growth between observed and expected at the second trimester scan, calculated by z-scores. Risk of birth of a severe SGA infant (birth weight for gestational age by fetal sex less than the 3^rd centile) was calculated using multivariable logistic regression analysis and presented as adjusted odds ratio (aOR).

Results

Parietal growth less than 2.5 percentile between first and second trimester ultrasound examination was associated with elevated risk of being born severe SGA. (aOR 1.67; 95% Confidence Interval 1.28–2.18). The risks of preterm severe SGA (birth before 37 weeks) and term severe SGA (birth 37 weeks or later) were at similar levels, and risk of severe SGA were also elevated in the absence of preeclampsia, hypertensive diseases or gestational diabetes.

Conclusions

Fetuses with slow growth of biparietal diameter at ultrasound examination in early second trimester exhibit increased risk of being born SGA independent of gestational age at birth and presence of maternal hypertensive diseases or diabetes mellitus.

Accelerated fetal growth in early pregnancy and risk of severe large-for-gestational-age and macrosomic infant: a cohort study in a low-risk population

INTRODUCTION

Our objective was to examine the association between fetal growth in early pregnancy and risk of severe large-for-gestational-age (LGA) and macrosomia at birth in a low-risk population.

MATERIAL AND METHODS

Cohort study that included 68 771 women with non-anomalous singleton pregnancies, without history of diabetes or hypertension, based on an electronic database on pregnancies and deliveries in Stockholm-Gotland Region, Sweden, 2008-2014. We performed multivariable logistic regression to estimate the association between accelerated fetal growth occurring in the first through early second trimester as measured by ultrasound and LGA and macrosomia at birth. Restricted analyses were performed in the groups without gestational diabetes and with normal body mass index (18.5-24.9 kg/m² ).

RESULTS

When adjusting for confounders, the odds of having a severely LGA or macrosomic infant were elevated in mothers with fetuses that were at least 7 days larger than expected as compared with mothers without age discrepancy at the second-trimester scan (adjusted odds ratio 1.80; 95% CI 1.23-2.64 and adjusted odds ratio 2.15; 95% CI 1.55-2.98, respectively). Additionally, mothers without gestational diabetes and mothers with normal weight had an elevated risk of having a severely LGA or macrosomic infant when the age discrepancy by second-trimester ultrasound was at least 7 days.

CONCLUSIONS

In a low-risk population, ultrasound-estimated accelerated fetal growth in early pregnancy was associated with an increased risk of having a severely LGA or macrosomic infant.

Prediction of small-for-gestational-age neonate by third-trimester fetal biometry and impact of ultrasound-delivery interval

OBJECTIVES

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.

METHODS

In this prospective study, data were collected from a multicenter singleton cohort study investigating the links between various exposures during pregnancy with birth outcome and later health in children. We included women, recruited in the first trimester, who had complete outcome data and had undergone third-trimester ultrasound examination. Demographic, clinical and biological variables were also collected from both parents. We compared prediction of delivery of a SGA neonate (birth weight < 10^th percentile) by the following methods: abdominal circumference (AC) Z-score based on Hadlock curves (Hadlock AC), on INTERGROWTH-21^st Project curves (Intergrowth AC) and on Salomon curves (Salomon AC); estimated fetal weight (EFW) Z-score based on Hadlock curves (Hadlock EFW) and on customized curves from Gardosi (Gardosi EFW); and fetal growth velocity based on change in AC between second and third trimesters (FGVAC). We also assessed the following ultrasound-delivery intervals: ≤ 4 weeks, ≤ 6 weeks and ≤ 10 weeks.

RESULTS

Third-trimester ultrasound was performed in 1805 patients with complete outcome data, of whom 158 (8.8%) delivered a SGA neonate. Ultrasound examination was at a median gestational age of 32 (interquartile range, 31-33) weeks. The ultrasound-delivery interval was ≤ 4 weeks in 17.2% of cases, ≤ 6 weeks in 48.1% of cases and ≤ 10 weeks in 97.3% of cases. Areas under the receiver-operating characteristics curve (AUC) were 0.772 for Salomon AC, 0.768 for Hadlock EFW, 0.766 for Hadlock AC, 0.765 for Intergrowth AC, 0.708 for Gardosi EFW and 0.674 for FGVAC (all P < 0.0001). The screening method with the highest AUC for an ultrasound-delivery interval ≤ 4 weeks was Salomon AC (AUC, 0.856), ≤ 6 weeks was Hadlock AC (AUC, 0.824) and ≤ 10 weeks was Salomon AC (AUC, 0.780). At a fixed 10% false-positive rate, the best detection rates were 60.0%, 54.1% and 42.1% for intervals ≤ 4, ≤ 6 and ≤ 10 weeks, respectively.

CONCLUSION

Third-trimester ultrasound measurements provide poor to moderate prediction of SGA. A shorter ultrasound-delivery interval provides better prediction than does a longer interval. Further studies are needed to test the effect of including maternal or biological characteristics in SGA screening. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Characterization of early changes in fetoplacental hemodynamics in a diet-induced rabbit model of IUGR

Intrauterine growth restriction (IUGR) is associated with adverse perinatal outcomes and late-onset diseases in offspring. Eating disorders, voluntary caloric restriction and maternal undernutrition can all induce IUGR but a relevant model is required to measure all its possible consequences. In this work, pregnant rabbits were used as an IUGR model. Control females (n=4) received ad libitum diet throughout pregnancy, whereas underfed females (n=5) were restricted to 50% of their daily requirements. Offspring size was measured by ultrasonography and in vivo at birth. Hemodynamic features of the umbilical cords and middle cerebral arteries (systolic peak velocity, end diastolic velocity, pulsatility index and resistance index) were characterized by Doppler ultrasonography. At day 21, maternal underfeeding resulted in a significant reduction of fetal size (occipito-nasal length). At birth, the size of kits from the underfed group was significantly lower (lower crown-rump length, biparietal and transversal thoracic diameters) and a reduced weight with respect to the control group. Feed restriction altered blood flow perfusion compared with does fed ad libitum (significant higher systolic peak, time-averaged mean velocities and lower end diastolic velocity). Fetuses affected by IUGR presented with compensative brain-sparing effects when compared with the control group. In conclusion, the present study supports using rabbits and the underfeeding approach as a valuable model for IUGR studies. These results may help to characterize IUGR alterations due to nutrient restriction of mothers in future research.

Maternal vitamin C deficiency during pregnancy results in transient fetal and placental growth retardation in guinea pigs

PURPOSE

Recently, we reported that preferential maternal-fetal vitamin C (vitC) transport across the placenta is likely to be impaired by prolonged maternal vitC deficiency. Maintenance of a basal maternal vitC supply at the expense of the fetus may impair fetal development; however, the knowledge of vitC's impact on intrauterine development is sparse. The aim of this study was to explore the effect of maternal vitC status on fetal and placental development in guinea pigs.

METHODS

Twenty pregnant Dunkin Hartley guinea pigs were randomized into four groups to receive diets either sufficient (918 mg/kg CTRL) or deficient (100 mg/kg DEF) in vitC. Cesarean sections at gestational day (GD) 45 or 56 allowed for fetal and placental measurements.

RESULTS

At GD45, body, brain and placental weights were significantly reduced in DEF pups compared with CTRL (p < 0.05, p < 0.001 and p < 0.05, respectively). DEF plasma vitC levels were ~6% of those of CTRL (p < 0.0001), and the fetal/maternal plasma vitC ratio was significantly reduced at GD56 in the DEF animals compared with controls (p = 0.035). Placental vitC levels were reduced in DEF animals (p < 0.0001) and the ascorbate oxidation ratio and glutathione elevated compared with controls (p < 0.0001).

CONCLUSIONS

Although no clinical differences between CTRL and DEF pups were observed at GD56, the present data suggest that vitC plays a role in early fetal development. Although no clinical differences between CTRL and DEF pups were observed at GD56, the present data suggest that vitC plays a role in early fetal development. Low maternal vitC intake during pregnancy may compromise maternal weight gain, placental function and intrauterine development.

A prospective observational study of early fetal growth velocity and its association with birth weight, gestational age at delivery, preeclampsia, and perinatal mortality

OBJECTIVES

We aimed to measure early fetal growth velocity and to correlate this with the birth weight, gestational age at delivery, and with the incidence of adverse pregnancy outcomes specifically preeclampsia and perinatal mortality.

METHODS

A data based prospective observational study, wherein sonographic biometry data and specific pregnancy outcome related data were collected from pregnant women's records, starting soon after their first antenatal visit. Early fetal growth velocity was measured using BPD growth between 11 and 14 weeks scan and anomaly scan and standardizing this by Z scoring.

RESULTS

Out of 607 fetuses, 41 (6.7%) were slow growing, 531 (87.4%) normally growing, and 35 (5.7%) fast growing (Z scoring <10th(,) 10-90th, and >90th percentiles respectively). As fetal growth velocity increased, the mean birth weight decreased from 2958.7±388.9 (<10th centile), 2742.1±576.6 (10-90th centile), to 2339.3±729.4 (>90th centile); and gestational age at delivery decreased from 38.5±1.3 (<10th centile), 37.5±2.1 (10-90th centile), to 36.4±2.2 (>90th centile), and both these trends were statistically significant (p<0.001).Faster growing fetuses had a higher risk of preterm delivery(spontaneous+indicated) compared to other 2 groups [OR 4.42 (2.18,8.98)], and slower growing fetuses had a higher risk of postdated deliveries compared to other 2 groups [OR 3.042 (1.44, 6.45)].We found no significant association between early fetal growth velocity and incidence of small for gestational age at birth/low birth weight at term, preeclampsia, and perinatal mortality.

CONCLUSIONS

Early fetal growth velocity between first and second trimesters, may be one of the important factors influencing ultimate birthweight and gestational age at delivery.

First trimester growth restriction and uterine artery blood flow in the second trimester as predictors of adverse pregnancy outcome

OBJECTIVES

To investigate if fetuses with first trimester growth restriction have poorer perfusion of the placenta compared to a control group, and to investigate whether first trimester growth restriction in combination with poor flow in the uterine arteries in the second trimester can be used to predict poor outcome.

STUDY DESIGN

Women with singleton pregnancies, where the gestational age estimated by crown-rump length (CRL) at the first trimester scan was 7 days or more smaller than the gestational age estimated by last menstrual period, and a control group of women, where the gestational age was either equal to or 1 day larger than the gestational age estimated by last menstrual period, were invited to join the study. The study entailed the routine scans; Down syndrome screening in gestational week 11-14 and an anomaly scan in gestational week 18-21. In addition to the routine scans the participants were offered a growth scan in gestational week 23-24. At the anomaly scan and growth scan, umbilical and uterine artery Doppler flows were measured.

RESULTS

182 cases and 230 controls were included in the study. The case and control groups showed no significant differences in placental blood flow characteristics at 18-21 weeks or 23-24 weeks. In our logistic regression models the only outcome that showed a significant association to the case group was birth weight below 2500 g. Having a CRL 7 days or more smaller than expected increased the risk of having a child with a birth weight below 2500 g with an odds ratio of 3.29.

CONCLUSIONS

We were unable to demonstrate a link between first trimester growth restriction and poor placental perfusion. The case group had increased risk of birth weight below 2500 g, but only with an odds ratio of 3. Therefore we do not recommend implementation of uterine or umbilical artery flow measurements specifically for fetuses with first trimester growth restriction.

Ultrasound evidence of early fetal growth restriction after maternal malaria infection

Background

Intermittent preventive treatment (IPT), the main strategy to prevent malaria and reduce anaemia and low birthweight, focuses on the second half of pregnancy. However, intrauterine growth restriction may occur earlier in pregnancy. The aim of this study was to measure the effects of malaria in the first half of pregnancy by comparing the fetal biparietal diameter (BPD) of infected and uninfected women whose pregnancies had been accurately dated by crown rump length (CRL) before 14 weeks of gestation.

Methodology/Principal Findings

In 3,779 women living on the Thai-Myanmar border who delivered a normal singleton live born baby between 2001–10 and who had gestational age estimated by CRL measurement <14 weeks, the observed and expected BPD z-scores (<24 weeks) in pregnancies that were (n = 336) and were not (n = 3,443) complicated by malaria between the two scans were compared. The mean (standard deviation) fetal BPD z-scores in women with Plasmodium (P) falciparum and/or P.vivax malaria infections were significantly lower than in non-infected pregnancies; −0.57 (1.13) versus −0.10 (1.17), p<0.001. Even a single or an asymptomatic malaria episode resulted in a significantly lower z-score. Fetal female sex (p<0.001) and low body mass index (p = 0.01) were also independently associated with a smaller BPD in multivariate analysis.

Conclusions/Significance

Despite early treatment in all positive women, one or more (a)symptomatic P.falciparum or P.vivax malaria infections in the first half of pregnancy result in a smaller than expected mid-trimester fetal head diameter. Strategies to prevent malaria in pregnancy should include early pregnancy.

Early fetal growth, PAPP-A and free β-hCG in relation to risk of delivering a small-for-gestational age infant

OBJECTIVES

To examine early fetal growth, pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotropin (β-hCG) in relation to the risk of delivering a small-for-gestational age (SGA) infant.

METHODS

Included in the study were 9450 singleton pregnant women who attended the prenatal screening program at Aarhus University Hospital, Denmark, between January 2005 and December 2007. Maternal serum levels of PAPP-A and free β-hCG were measured between gestational weeks 8 and 13. Two ultrasound examinations were performed, the first at 11-13 weeks and the second at 18-22 weeks, from which gestational age was estimated based on crown-rump length and biparietal diameter, respectively. Early fetal growth was expressed as an index: the ratio between the estimated number of days from the first to the second scan and the actual calendar time elapsed in days. SGA was defined as birth weight < 5(th) centile for gestational age, and the risk of SGA was evaluated according to different cut-offs of the early fetal growth index and the serum markers.

RESULTS

PAPP-A < 0.4 MoM combined with an early fetal growth index < 10(th) centile resulted in an increased risk of SGA (odds ratio (OR), 5.8; 95% CI, 2.7-12.7). Low PAPP-A, low free β-hCG and slow early fetal growth were statistically, independently associated with SGA, and the association between free β-hCG < 0.3 MoM and SGA was as strong as that between PAPP-A < 0.3 MoM and SGA (OR, 3.1 and 3.0, respectively).

CONCLUSION

The combination of slow early fetal growth and low PAPP-A resulted in a nearly six-fold increased risk of delivery of an SGA infant. These findings might improve our chances of early identification of fetuses at increased risk of growth restriction.

Early biometric lag in the prediction of small for gestational age neonates and preeclampsia

OBJECTIVE

An early fetal growth lag may be a marker of future complications. We sought to determine the utility of early biometric variables in predicting adverse pregnancy outcomes.

METHODS

In this retrospective cohort study, the crown-rump length at 11 to 14 weeks and the head circumference, biparietal diameter, abdominal circumference, femur length, humerus length, transverse cerebellar diameter, and estimated fetal weight at 18 to 24 weeks were converted to an estimated gestational age using published regression formulas. Sonographic fetal growth (difference between each biometric gestational age and the crown-rump length gestational age) minus expected fetal growth (number of days elapsed between the two scans) yielded the biometric growth lag. These lags were tested as predictors of small for gestational age (SGA) neonates (≤10th percentile) and preeclampsia.

RESULTS

A total of 245 patients were included. Thirty-two (13.1%) delivered an SGA neonate, and 43 (17.6%) had the composite outcome. The head circumference, biparietal diameter, abdominal circumference, and estimated fetal weight lags were identified as significant predictors of SGA neonates after adjusted analyses (P < .05). The addition of either the estimated fetal weight or abdominal circumference lag to maternal characteristics alone significantly improved the performance of the predictive model, achieving areas under the curve of 0.72 and 0.74, respectively. No significant association was found between the biometric lag variables and the development of preeclampsia.

CONCLUSIONS

Routinely available biometric data can be used to improve the prediction of adverse outcomes such as SGA. These biometric lags should be considered in efforts to develop screening algorithms for adverse outcomes.

Diagnosis and management of fetal growth restriction

Fetal growth restriction (FGR) remains a leading contributor to perinatal mortality and morbidity and metabolic syndrome in later life. Recent advances in ultrasound and Doppler have elucidated several mechanisms in the evolution of the disease. However, consistent classification and characterization regarding the severity of FGR is lacking. There is no cure, and management is reliant on a structured antenatal surveillance program with timely intervention. Hitherto, the time to deliver is an enigma. In this paper, the challenges in the diagnosis and management of FGR are discussed. The biophysical profile, Doppler, biochemical and molecular technologies that may refine management are reviewed. Finally, a model pathway for the clinical management of pregnancies complicated by FGR is presented.

The relationship between first trimester fetal growth, pregnancy-associated plasma protein A levels and birthweight

OBJECTIVE

We sought to define the relationship between first trimester fetal growth, pregnancy-associated plasma protein A (PAPP-A) levels and birthweight.

METHODS

Two-hundred and one women with repeat first trimester crown-rump length (CRL) measurements were included. In 194, the first trimester PAPP-A value was known and in 169 there was complete data including birthweight. Fetal growth curves were derived using functional linear discriminant analysis (FLDA) and growth compared between those with < 10th percentile, 10th to 90th and > 90th percentile PAPP-A multiple of median (MoM) levels and birthweight percentiles.

RESULTS

Median maternal age was 35 years, gestation at PAPP-A sampling and of first scan was 11 weeks. Median delivery gestation was 40 weeks and birthweight 3425 g. There was no association between first trimester fetal CRL growth and either PAPP-A MoM percentile or birthweight percentile. There was a significant positive correlation between PAPP-A MoM and birthweight percentile (p = 0.0004).

CONCLUSIONS

First trimester fetal growth rate is not related to birthweight percentile or first trimester PAPP-A levels. Irrespective of gestation, a low PAPP-A is associated with delivery of a smaller baby, and a high PAPP-A with a larger baby.

Maternal serum placental growth hormone, but not human placental lactogen or insulin growth factor-1, is positively associated with fetal growth in the first half of pregnancy

OBJECTIVE

To investigate if maternal levels of human placental lactogen (hPL), placental growth hormone (PGH) and insulin-like growth factor-1 (IGF-1) are associated with growth rate of the biparietal diameter (BPD) in the first half of pregnancy.

METHODS

Data on 8215 singleton fetuses from the Copenhagen First Trimester Study with measurements of BPD from ultrasound scans performed at weeks 11-14 and 17-21 of pregnancy were analyzed. Growth rate was defined as millimeters of growth/day of BPD between the two scans. Fetuses with growth rate below the 2.5(th) centile (low growth rate, n = 203) and above the 97.5(th) centile (high growth rate, n = 203) were identified. As a reference group 212 fetuses with growth rate around the median were identified (intermediate growth rate). Out of the 618 selected cases in the three growth rate groups a total of 463 cases had a blood sample taken at the time of first-trimester ultrasound (5.6% of the original sample size of 8215 pregnancies). The maternal blood serum concentrations of hPL, PGH and IGF-1 were determined in the three different growth-rate groups. Linear regression analysis without adjustment and with adjustment for known and potential confounders was used to compare serum levels between the groups.

RESULTS

Simple linear regression showed a difference in serum level of log(10) PGH between the high and intermediate growth-rate groups (P = 0.037). When adjusted for maternal weight and crown-rump length, multiple linear regression analysis confirmed this difference, as fetuses with high growth rates had a 12% (95% confidence interval, 2-20%; P = 0.009) higher maternal serum level of PGH than those with intermediate growth rates. No differences in hPL and IGF-1 levels between the three different growth-rate groups were found after simple and multiple linear regression analysis.

CONCLUSION

Maternal PGH levels are higher in women carrying fetuses with high first-trimester growth rates than in controls, both in a simple unadjusted analysis and in analyses adjusted for known and potential confounders. Thus, PGH may be involved in fetal growth regulation as early as in the first trimester of pregnancy.

Low PAPP-A in the first trimester is associated with reduced fetal growth rate prior to gestational week 20

OBJECTIVE

To evaluate the association between maternal pregnancy-associated plasma protein-A (PAPP-A) and fetal growth from the first to the second trimester.

METHODS

A prospective cohort study including 8347 pregnant women attending prenatal care at Aarhus University Hospital were conducted. PAPP-A was measured during 8 to 14 gestational weeks. Fetal growth between the two scans in the first and second trimesters was estimated by (GA(20)- GA(12))/Days(calendar), where GA(12) reflects gestational age in days calculated from crown-rump length at a 12-week scan, GA(20) reflects gestational age in days calculated from biparietal diameter at a 20-week scan, and Days(calendar) reflects the number of calendar days between the two scans.

RESULTS

Fetal growth rate from the first to the second trimester was correlated with PAPP-A, with a regression coefficient of 0.009 (95% CI, 0.007-0.012, P < 0.001). PAPP-A below 0.30 MoM was associated with a fetal growth rate below the tenth centile, with an adjusted OR of 2.05 (95% CI, 1.24-3.38).

CONCLUSION

Low levels of PAPP-A are associated not only with low birth weight at term but also with slower fetal growth prior to 20 weeks of gestation.

First-trimester assessment of placenta function and the prediction of preeclampsia and intrauterine growth restriction

Preeclampsia and intrauterine growth restriction (IUGR) are major contributors to perinatal mortality and morbidity worldwide. Both are characterized by impaired trophoblastic invasion of the maternal spiral arteries and their conversion from narrow muscular vessels to wide non-muscular channels. Despite improvement in the understanding of the pathophysiology of these conditions, ability to accurately identify pregnant woman who will develop them is limited. This greatly impairs the development and testing of preventive interventions. While different measures of placental dysfunction have been associated with increased risk for adverse pregnancy outcomes, the ability of any single one to accurately predict these outcomes is poor. Developing predictive tests is further challenged by difficulty in the timing of the measurements, as both the structural and biochemical characteristics of the placenta change with increasing gestational age. The ideal screening test would accurately predict the development of adverse pregnancy outcomes early enough to provide a window for preventive interventions. Improvement in ultrasound technology provides potentially useful novel tools for evaluating placental structure, but measurements need to be standardized in order to be useful. Maternal serum analyte screening is a noninvasive test of placental biochemical function, but present serum marker alone is not sufficiently accurate to suggest its routine use in clinical practice. The use of first trimester biochemical markers in combination with uterine artery Doppler screening is promising as a potential screening tool. Prospective longitudinal studies using standardized methodology are necessary to further evaluate the choice of parameters and strategies of combination to achieve the best predictive models.

Benzopyrene and experimental stressors cause compensatory differentiation in placental trophoblast stem cells

Stress causes decreased cell accumulation in early periimplantation embryos and the placental trophoblast stem cells derived from them. Benzopyrene and many other stressors activate stress enzymes that lead to suppressed stem cell accumulation through diminished proliferation and increased apoptosis. Trophoblast stem cells proliferate and a subpopulation of early postimplantation trophoblast cells differentiate to produce the first placental hormones that arise in the implanting conceptus. These hormones mediate antiluteolytic effects that enable the continuation of a successful implantation. The normal determination and differentiation of placental trophoblast stem cells is dependent upon a series of transcription factors. But, these transcription factors can also be modulated by stress through the activity of stress enzymes. This review enumerates and analyzes recent reports on the effects of benzopyrene on placental function in terms of the emerging paradigm that placental differentiation from stem cells can be regulated when insufficient production of stem cells is caused by stress. In addition, we review the other effects caused by benzopyrene throughout placental development.