Small For Gestational Age Odds Ratio Research Articles

Association between Heated Tobacco Product Use during Pregnancy and Fetal Growth in Japan: A Nationwide Web-Based Survey.

Combustible cigarette smoking impacts fetal growth during pregnancy. However, the risk associated with heated tobacco products (HTPs) remains unclear. This nationwide cross-sectional study investigated whether HTP use during pregnancy is associated with small for gestational age (SGA) outcomes among 5647 post-delivery women with singleton pregnancies, which were divided into four groups: lifetime never-smokers, former smokers before pregnancy, and current smokers for each of the tobacco products during pregnancy (sole HTP and sole combustion smokers). Information on the prevalence of SGA, defined as birth weight and height below the 10th percentile, was retrieved from the Maternal and Child Health Handbooks of post-delivery women. Using logistic regression, the association between sole HTP smokers during pregnancy and SGA, adjusted for covariates, with lifetime never-smokers as reference, was investigated. The prevalence was: current sole HTP smokers during pregnancy, 1.8% (102/5647); and SGA, 2.9% (164/5647). Sole HTP smokers during pregnancy had a higher prevalence of SGA (5.9% [6/102] vs. 2.7% [111/4144]) with an adjusted odds ratio (OR) of 2.50 (95% confidence interval [CI], 1.03–6.05) than lifetime never-smokers. Among sole combustion smokers, the adjusted OR for SGA was 1.95 (95% CI, 0.81–4.67). In Japan, HTP smoking during pregnancy may be associated with an increased risk for SGA.

Effects of early maternal cancer and fertility treatment on the risk of adverse birth outcomes

SummaryBackgroundEarly maternal cancer and fertility treatment each increase the risk for adverse birth outcomes, but the joint effect of these outcomes has not yet been reported. Thus, the aim was to assess the individual and joint effect of maternal cancer and fertility treatment on the risk for adverse birth outcomes.MethodsThis population-based cohort study included 5487 live-born singletons identified in the Danish Medical Birth Register (1994–2016) of mothers with previous cancer (<40 years) recorded in the Danish Cancer Registry (1955–2014). We randomly selected 80,262 live-born singletons of mothers with no cancer <40 years matched to mothers with cancer by birth year and month. We calculated odds ratios (ORs) for preterm birth, low birth weight (LBW) (<2500 g) and small for gestational age (SGA), mean differences in birth weight in grams, and additional cases of preterm birth (gestational age<259 days) per 100,000 person-years. Multiplicative and additive interaction of maternal cancer and fertility treatment was compared with outcomes of children conceived naturally to mothers with no maternal cancer (reference group).FindingsAmong 84,332 live-born singletons, increased ORs for preterm birth were observed among children born to mothers with previous cancer (1·48, 95% confidence interval [CI] 1·33–1.65) or after fertility treatment (1·43, 95% 1·28–1–61), with 22 additional cases of preterm birth among both group of children (95% CI 15–29; 95% CI 14–30). In the joint analyses, the OR for SGA for children born after fertility treatment to mothers with previous cancer was similar to that of the reference group (OR 1·02, 95% CI 0·72–1·44, P for interaction=0·52). Children with both exposures had increased ORs for LBW (1·86, 95% CI 1·17–2·96, P for interaction=0·06) and preterm birth (2·31, 955 CI 1·66–3·20, P for interaction = 0·56), with 61 additional cases of preterm birth (95% CI 27–95, P for interaction=0.26) over that of children in the reference group. The mean birth weight was also lower in children born to mothers with both exposures (-140 g, 95% CI -215; -65) (P for interaction=0.06) but decreased to -22 g (95% CI -76; 31) after adjustment for GA.InterpretationAlthough we did not find any statistically significant additive interaction between maternal cancer and fertility treatment, children born after fertility treatment of mothers with previous cancer were at increased risk for adverse birth outcomes. Thus, pregnant women with both exposures need close follow-up during pregnancy.FundingThe Danish Cancer Society and the Danish Childhood Cancer Foundation.

Maternal Serum Antioxidants in Mid Pregnancy and Risk of Preterm Delivery and Small for Gestational Age Birth: Results from a Prospective Pregnancy Cohort.

Background: Preterm delivery (PTD) and poor fetal growth are major contributors to neonatal mortality and morbidity that can extend from birth onward. Although overt maternal nutrient deficiencies are associated with adverse pregnancy outcomes, such deficiencies are rare in developed countries. However, some evidence suggests that even within the normal range, higher levels of antioxidant nutrients are protective against adverse pregnancy outcomes. Materials and Methods: Using data from the prospective Pregnancy Outcomes and Community Health (POUCH) Study (n = 301 preterm; n = 246 term), we examined associations between maternal blood levels of selected antioxidants and pregnancy outcomes. Serum collected at 16-27 weeks' gestation was analyzed for carotenoids, retinol, and α- and γ-tocopherol. Using weighted polytomous regression, these nutrient concentrations were assessed in relation to (1) PTD (<37 weeks gestation) overall and grouped as spontaneous or medically indicated; and (2) small for gestational age (SGA) defined as birthweight-for-gestational age <10th percentile of a national reference population. Results: Women with total serum carotenoids in the upper quartile (Q4) had significantly lower odds of medically indicated PTD compared with women in the lower quartiles (Q1-Q3) even after adjustment for maternal characteristics (aOR = 0.4; 95% CI: 0.2-0.9). Odds ratios for SGA were consistently ≤0.5 among women with any of the serum nutrients in Q4 as compared with Q1-Q3, but final models did not reach statistical significance. Conclusion: Results support the possibility that high maternal serum antioxidants and/or the larger dietary or lifestyle pattern they represent may play a protective role in preventing adverse pregnancy outcomes.

The interaction between maternal smoking, illicit drug use and alcohol consumption associated with neonatal outcomes.

The adverse effects of smoking on neonatal outcomes, such as small-for-gestational-age (SGA), has been extensively studied however, the consequences of smoking combined with alcohol and/or drug use is less clear. This retrospective observational study analyzed clinical and sociodemographic details of 40156 women who delivered a singleton baby between the years 2011 and 2015. Compared with women who had never smoked, smokers who did not engage in alcohol or drug use had an odds ratio (OR) of delivering a baby who was SGA of 3.2 (95% CI: 3.1-3.5). Smokers who used illicit drugs in isolation or in combination with alcohol during pregnancy had higher ORs for SGA (1.4, 95% CI: 1.1-1.7, P = 0.006 and 1.8, 95% CI: 1.2-2.7, P = 0.007) compared to women who smoked but did not engage in alcohol or drug use in pregnancy. These women also delivered babies with lower mean birthweights (125 g, P < 0.001 and 181.4 g, P = 0.003) and head circumferences (0.4 cm, P < 0.001 and 0.3 cm, P = 0.048). Women who smoked and used alcohol, but not illicit drugs were not associated adverse outcomes above that of smoking in isolation. Illicit drug use combined with maternal smoking during pregnancy increases the risk of adverse neonatal outcomes above that of smoking in isolation.

Birth Outcomes in Children Fathered by Men Treated with Anti-TNF-α Agents Before Conception.

The safety of paternal use of anti-tumor necrosis factor-α (TNF-α) agents immediately prior to conception is practically unknown. On the basis of nationwide data from Danish health registries, we examined the association between paternal use of anti-TNF-α agents within 3 months before conception and adverse birth outcomes. This nationwide cohort study is based on data from all women who had a live born singleton child in Denmark from 1 January 2007 through 2013. Children fathered by men treated with anti-TNF-α agents within three months before conception constituted the exposed cohort (N=372), and children fathered by men not treated before conception constituted the unexposed cohort (N=399,498). The outcomes were congenital abnormalities (CAs), preterm birth, and small for gestational age (SGA). We adjusted for multiple covariates, and considered paternal underlying disease and concomitant medication. The adjusted risks of CAs and preterm birth were close to unity, and the adjusted odds ratio (OR) for SGA was 1.70 (95% confidence interval (CI): 0.94-3.09). Restricting our analysis to fathers with inflammatory bowel disease, we found no increased risk of CAs or SGA, and the adjusted OR for pretem birth was 1.42 (95% CI: 0.52-3.86). Restricting our analysis to fathers with rheumatologic/dermatological diseases, we found no increased risk of CAs or preterm birth, and the adjusted OR for SGA was 1.70 (95% CI: 0.74-3.89). Our results are overall reassuring regarding the safety of paternal preconceptional use of anti-TNF-α agents. The result regarding SGA should, however, be interpreted with caution as we found an increased risk, although not significantly increased.

Predicting SGA neonates using first-trimester screening: influence of previous pregnancy’s birthweight and PAPP-A MoM

Objective: Investigating the proportions of anamnestic and biochemical variables of the previous and current pregnancies for the prediction of small for gestational age (SGA) neonates in the current pregnancy.Methods: In this observational retrospective study, 45 029 pregnancies were examined, including 3862 patients with more than one pregnancy. Odds ratios for SGA using anamnestic parameters and pregnancy-associated plasma protein A (PAPP-A) values from all pregnancies were estimated by using a logistic regression model.Results: There were 2552 (5.7%) SGA neonates. Two threshold PAPP-A values were identified at 0.15 MoM and 0.33 MoM with probabilities for SGA of 23% and 17%, respectively. A previous SGA < 10th centile and a current PAPP-A MoM value < 5th centile result in odds ratios of 4.8 (95% CI: 3.5–6.5) and 3.0 (95% CI: 1.8–5.0), respectively. The parameters’ combined odds ratio is 14.1 (95% CI: 3.9–50.3) with a number needed to screen of ten for one SGA neonate at a detection rate of 37%.Conclusion: Information on previous pregnancies affected by SGA and a current pregnancy’s low PAPP-A value are reliable predictors for a SGA delivery. First-trimester biochemical analysis should be maintained to detect women at risk for delivering a SGA neonate.

Fetal growth and maternal exposure to particulate air pollution -- More marked effects at lower exposure and modification by gestational duration

While there is growing evidence that air pollution reduces fetal growth, results are inconclusive with respect to the gestational window of effect. We investigated maternal exposure to particulate matter (PM10) in association with birth weight and fetus growth with a focus on the shape of the association and gestational age at birth as a potential effect modifier.The study population consisted of 525,635 singleton live births in Flanders (Belgium) between 1999 and 2009. PM10 exposure at maternal residence was averaged over various time windows. We used robust linear and logistic regression to estimate the effect of PM10 on birth weight and small for gestational age (SGA). Segmented regression models were applied for non-linear associations.Among moderately preterm (32–36 weeks) and term (>36 weeks) births, we found significant lower birth weight for all studied time windows. The estimated reduction in birth weight for a 10µg/m3 increase in average PM10 during pregnancy was 39.0g (95% confidence interval [CI]: 26.4, 51.5g) for moderately preterm births and 24.0g (95% CI: 20.9, 27.2g) for term births. The corresponding odds ratios for SGA were 1.19 (95% CI: 1.07, 1.32) and 1.09 (95% CI: 1.06, 1.12) respectively. Segmented regression models showed stronger effects of PM10 on fetal growth at lower concentrations.Maternal PM10 exposure was significantly associated with a reduction in fetal growth among term and moderately preterm births, with a tendency of stronger effects for the latter and a flattening out of the slope at higher PM10 concentrations.

Risk of Esophagitis Among Individuals Born Preterm or Small for Gestational Age

The association between gastroesophageal reflux and esophageal adenocarcinoma is likely to be mediated by inflammation. Reflux is common in infancy; the esophageal mucosa of infants born preterm or small for gestational age (SGA) could be particularly vulnerable. We investigated the association between preterm or SGA birth and risk of esophagitis early in life. We analyzed data from the Swedish birth register and the Swedish patient register to identify birth characteristics of individuals with endoscopically verified esophagitis from 1973 to 2007 and to determine their outcomes (7358 cases). Five controls were selected randomly and matched with each case (N = 38,479). Multivariable conditional logistic regression models were used to provide odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for potential confounding. The risk of esophagitis was increased among individuals born preterm (≤32 gestational weeks) (OR, 2.74; 95% CI, 2.15-3.49) or SGA (OR, 1.49; 95% CI, 1.32-1.68). When data were stratified by age at diagnosis and by sex, different risk patterns appeared. Among individuals diagnosed with esophagitis 9 years of age and younger, the OR for prematurity was 6.82 (95% CI, 4.65-10.03) and the OR for SGA at birth was 1.98 (95% CI, 1.55-2.52). Furthermore, the association with preterm birth was stronger among males (OR, 9.88; 95%, CI 5.93-16.45) than females (OR, 3.41; 95% CI, 1.81-6.41), whereas the association with SGA was stronger among females (OR, 2.50; 95% CI, 1.76-3.55) than males (OR, 1.64; 95% CI, 1.16-2.30). The risk of being diagnosed with esophagitis at age 20 or younger was not associated with preterm birth (OR, 1.02; 95% CI, 0.64-1.63), but was associated with being SGA at birth (OR, 1.31; 95% CI, 1.11-1.54). Preterm birth is associated with esophagitis only during childhood, whereas SGA birth is associated with esophagitis during adolescence as well. The associations appear to differ between sexes.

Effect of water disinfection type on adverse fetal outcomes

The authors found small increased risks of preterm delivery (PTD) for chlorinated surface water, chlorinated groundwater, chloraminated water, and all other types of disinfected drinking water (range = 1.09–1.20) compared with untreated groundwater. Similar odds ratios (range = 1.08–1.16) were detected for small‐for‐gestational‐age (SGA) measurements and exposure to chlorinated surface water, chloraminated water, and other water disinfectants. A reduction in mean birth weight for these three exposure groups (range = 29–V39 g) was also found. Small differences in mean birth weight (≤ 16 g) were detected among chlorinated surface water users (versus chloraminated surface water), but odds ratios for SGA and PTD were comparable. Although associations were detected for disinfected drinking water exposure categories relative to untreated groundwater, the data suggest that risk of adverse birth outcomes among consumers of different types of disinfected drinking water were comparable in this study population.

First-Trimester Biochemical Markers of Aneuploidy and the Prediction of Small-for-Gestational Age Fetuses

Measurement in the first trimester of blood levels of the placentally derived biochemical markers pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotropin (β-hCG), together with ultrasound measurement of nuchal translucency thickness, are increasingly being used as part of screening programs for trisomy 21 and other aneuploidies. Preliminary studies have suggested that reduced levels of PAPP-A and free β-hCG could be useful for identifying pregnancies that result in small-for-gestational age (SGA) infants and other adverse outcomes. This study evaluated the ability of measurement of free β-hCG and PAPP-A levels to predict SGA in a cohort of 49,801 British women prospectively screened in the first trimester. Between 1998 and 2003, singleton pregnant women presenting for maternity care at United Kingdom hospitals were screened for trisomy 21 by combined measurement of maternal serum free β-hCG and PAPP-A and nuchal translucency thickness scans at 11 + 0 to 13 + 6 weeks of gestation. All study participants had complete outcome data and normal fetal karyotypes. The free β-hCG and PAPP-A measurements were expressed as multiples of the expected normal median (MOM) for a pregnancy of the same gestational age. The control group consisted of 46,262 pregnancies resulting in live births at full term; the study group included 3539 pregnancies resulting in live births of SGA infants, divided into 3 subgroups based on birth weight below the 10th, fifth, and third centiles for gestational age. The association between these 2 biochemical markers and the frequency of SGA were investigated by comparing the relative incidence of each marker at a number of MoM cutoffs and various birth weight centile cutoffs. The median PAPP-A level was significantly lower in the SGA group than in the normal group for all 3 categories of SGA (P < 0.001). When the PAPP-A level was 0.415 MoM, which corresponded to the fifth percentile in the normal group, the odds ratios for SGA below the 10th, fifth, and third percentiles were 2.70, 3.21, and 3.66, respectively, and the respective detection rates for SGA were 12.0%, 14.0%, and 16.0%. Significant differences in free β-hCG MoM between the SGA group and the normal group were not found (P = ns). The investigators believe that these findings together with earlier studies provide sufficient evidence to use low levels of maternal serum PAPP-A to help in identifying the pregnancies at increased risk for delivery of an SGA infant.

Association of isolated short femur in the mid‐trimester fetus with perinatal outcome

To evaluate the prevalence of fetal isolated short femur in a cohort of women screened for Down syndrome by the integrated test, and to compare the outcome of fetuses with isolated short femur in the mid-trimester with that of fetuses with normal femur length (controls). This was a retrospective cohort study of 1262 women booked for antenatal care and delivery at University College London Hospital. All women had integrated testing in the late first and early second trimesters and a detailed anomaly scan in the mid-trimester. All scan reports, screening results and neonatal data were analyzed statistically. The fetal femur was short (< 5(th) percentile) in 5.1% of patients and 4.7% had isolated short femur. In pregnancies with isolated short femur, the birth weight was significantly lower and there were higher rates of small-for-gestational age (SGA) and low birth weight (LBW) infants, compared with controls (P < 0.01). The odds ratios for SGA and LBW in pregnancies with isolated short femur were 3.0 (95% CI, 1.5-5.9) and 2.60 (95% CI, 1.1-6.2), respectively. Isolated short femur was associated significantly with low levels of pregnancy-associated plasma protein-A (P = 0.001). Isolated short femur in the mid-trimester fetus is associated with fetal growth restriction and SGA. In the context of normal Down syndrome screening and a normal anomaly scan, this marker should be regarded as a predictor for SGA, and fetal growth should be monitored during these pregnancies.

First-Trimester Markers of Aneuploidy and the Prediction of Small-for-Gestational Age Fetuses

First-trimester estimates of 2 biomarkers of placental origin, pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotropin (β-hCG), are increasingly used along with ultrasound measurement of nuchal translucency thickness to screen for trisomy 21 and other aneuploidies. There are preliminary indications that reduced levels of these markers—especially PAPP-A—may help to identify at-risk pregnancies including those resulting in delivery of a small-for-gestational age (SGA) infant. The study population included singleton pregnancies with chromosomally normal fetuses that were screened at 11 to 14 weeks’ gestation. Biochemical marker levels were converted to multiples of the expected normal median (MoM) for a pregnancy of the same gestational age. Associations between levels of free β-hCG and PAPP-A and the incidence of SGA were assessed by comparing relative incidence rates at MoM cutoffs and birth weight centile cutoffs. A total of 46,262 pregnancies resulted in live births of infants weighing at or above the 10th centile, whereas 3539 others produced SGA infants weighing less than the 10th centile for gestation. The risk of an SGA infant was significantly and inversely associated with maternal serum PAPP-A MoM, but not with free β-hCG MoM. In pregnancies with PAPP-A levels below the 10th, 5th, and 3rd percentile, the incidence of SGA was 12%, 14%, and 16%, respectively, and the odds ratios for SGA were 2.70, 3.21, and 3.66, respectively. Free β-hCG levels did not predict SGA. The investigators believe that, in the presence of a normal fetal karyotype, low maternal serum levels of PAPP-A are associated with an elevated risk of subsequently delivering a SGA infant. Low levels presumably indicate impaired placentation. Present evidence warrants using low PAPP-A to help identify SGA pregnancies.

First‐trimester biochemical markers of aneuploidy and the prediction of small‐for‐gestational age fetuses

To examine the clinical utility of the first-trimester biochemical markers of aneuploidy in their ability to predict subsequent delivery of a small-for-gestational age (SGA) infant. We examined singleton pregnancies with no chromosomal abnormality and with complete outcome data that had undergone screening for trisomy 21 by a combination of fetal nuchal translucency (NT) thickness and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 and 13 + 6 weeks' gestation. The biochemical markers were converted to multiples of the expected normal median (MoM) for a pregnancy of the same gestation. The association between free beta-hCG and PAPP-A and the incidence of SGA were assessed by comparing the relative incidence at MoM cut-offs and birth-weight centile cut-offs. At various marker levels the likelihood ratios (LR) for SGA were also calculated after excluding other adverse pregnancy complications. There were 46,262 pregnancies resulting in live births with birth weight at or above the 10(th) centile, and 3,539 below the 10(th) centile for gestation (SGA). There was a significant inverse association between the risk for SGA and maternal serum PAPP-A MoM but not free beta-hCG MoM. At the 5(th) centile of the normal outcome group for PAPP-A (0.415 MoM) the odds ratios for SGA below the 10(th), 5(th) and 3(rd) centiles of normal were 2.70, 3.21 and 3.66 and the respective detection rates for SGA were 12.0%, 14.0% and 16.0%. Low levels of maternal serum PAPP-A are associated, in the absence of an abnormal karyotype, with an increased risk for subsequent delivery of an SGA infant.

Milk consumption during pregnancy is associated with increased infant size at birth: prospective cohort study

Background: Cow milk contains many potentially growth-promoting factors.Objective: The objective was to examine whether milk consumption during pregnancy is associated with greater infant size at birth.Design: During 1996–2002, the Danish National Birth Cohort collected data on midpregnancy diet through questionnaires and on covariates through telephone interviews and ascertained birth outcomes through registry linkages. Findings were adjusted for mother’s parity, age, height, prepregnant BMI, gestational weight gain, smoking status, and total energy intake; father’s height; and family’s socioeconomic status The analyses included data from 50 117 mother-infant pairs.Results: Mean (±SD) consumption of milk was 3.1 ± 2.0 glasses/d. Milk consumption was inversely associated with the risk of small-for gestational age (SGA) birth and directly with both large-for-gestational age (LGA) birth and mean birth weight (P for trend < 0.001). In a comparison of women drinking ≥6 glasses/d with those drinking 0 glasses/d, the odds ratio for SGA was 0.51 (95% CI: 0.39, 0.65) and for LGA was 1.59 (1.16, 2.16); the increment in mean birth weight was 108 g (74, 143 g). We also found graded relations (P < 0.001) for abdominal circumference (0.52 cm; 0.35, 0.69 cm), placental weight (26 g; 15, 38 g), birth length (increment: 0.31 cm; 0.15, 0.46 cm), and head circumference (0.13 cm; 0.04, 0.25 cm). Birth weight was related to intake of protein, but not of fat, derived from milk.Conclusion: Milk intake in pregnancy was associated with higher birth weight for gestational age, lower risk of SGA, and higher risk of LGA.

Risk factors for small-for-gestational age births among infants in Brazil

To assess the risk factors for small-for-gestational-age (SGA) births. All live births occurring in the city of Pelotas, Brazil, between October and December 1993 were identified and mothers interviewed soon after delivery. Birthweight was recorded by the maternity staff. Gestational age was obtained from the mothers' recall of their date of last menstrual period. SGA was defined as a birthweight below the 10th percentile for gestational age and sex, according to the reference developed by Williams. Chi-square test and logistic regression were used in the crude and multivariate analysis, respectively. In all, 1082 births were identified. The prevalence of SGA was 13.1%. Even after adjusting for possible confounding variables, the odds ratio for SGA among those infants whose family income was <1 minimum wage was 8.81 (95% CI, 1.12-69.46) times higher than among those for infants with a family income > or = minimum wage. An antenatal care of low quality was associated with an odds ratio of 3.28 (95% CI, 1.09-9.91) for SGA. Short maternal stature and maternal smoking during pregnancy were also associated with SGA births. Low socioeconomic status, maternal smoking during pregnancy, maternal height and an antenatal care of low quality are the main risk factors for SGA births.

High and Low Hemoglobin Levels During Pregnancy

In Brief Objective To examine the association of maternal hemoglobin during pregnancy with preterm birth and small for gestational age (SGA). Methods We performed a retrospective cohort analysis of hemoglobin and birth outcome among 173,031 pregnant women who attended publicly funded health programs in ten states and delivered a liveborn infant at 26–42 weeks' gestation. We defined preterm as less than 37 weeks' gestation and SGA as less than the tenth percentile of a US fetal growth reference. Results Risk of preterm birth was increased in women with low hemoglobin level in the first and second trimester. The odds ratio (OR) for preterm birth with moderate-to-severe anemia during the first trimester (more than three standard deviations [SD] below reference median hemoglobin, equivalent to less than 95 g/L at 12 weeks' gestation) was 1.68 (95% confidence interval [CI] 1.29, 2.21). Anemia was not associated with SGA. High hemoglobin level during the first and second trimester was associated with SGA but not preterm birth. The ORs for SGA in women with very high hemoglobin level during the first and second trimester (more than three SDs above reference median hemoglobin, equivalent to greater than 149 g/L at 12 weeks' gestation and greater than 144 g/L at 18 weeks') were 1.27 (95% CI 1.02, 1.58) and 1.79 (95% CI 1.49, 2.15), respectively. Conclusion These data highlight the importance of considering anemia and high hemoglobin level as indicators for adverse pregnancy outcome. An elevated hemoglobin level (greater than 144 g/L) is an indicator for possible pregnancy complications associated with poor plasma volume expansion, and should not be mistaken for good iron status. Maternal anemia during pregnancy is associated with preterm birth, whereas high hemoglobin level is associated with small for gestational age.

High and low hemoglobin levels during pregnancy: differential risks for preterm birth and small for gestational age

Objective: To examine the association of maternal hemoglobin during pregnancy with preterm birth and small for gestational age (SGA). Methods: We performed a retrospective cohort analysis of hemoglobin and birth outcome among 173,031 pregnant women who attended publicly funded health programs in ten states and delivered a liveborn infant at 26–42 weeks’ gestation. We defined preterm as less than 37 weeks’ gestation and SGA as less than the tenth percentile of a US fetal growth reference. Results: Risk of preterm birth was increased in women with low hemoglobin level in the first and second trimester. The odds ratio (OR) for preterm birth with moderate-to-severe anemia during the first trimester (more than three standard deviations [SD] below reference median hemoglobin, equivalent to less than 95 g/L at 12 weeks’ gestation) was 1.68 (95% confidence interval [CI] 1.29, 2.21). Anemia was not associated with SGA. High hemoglobin level during the first and second trimester was associated with SGA but not preterm birth. The ORs for SGA in women with very high hemoglobin level during the first and second trimester (more than three SDs above reference median hemoglobin, equivalent to greater than 149 g/L at 12 weeks’ gestation and greater than 144 g/L at 18 weeks’) were 1.27 (95% CI 1.02, 1.58) and 1.79 (95% CI 1.49, 2.15), respectively. Conclusion: These data highlight the importance of considering anemia and high hemoglobin level as indicators for adverse pregnancy outcome. An elevated hemoglobin level (greater than 144 g/L) is an indicator for possible pregnancy complications associated with poor plasma volume expansion, and should not be mistaken for good iron status.

The obstetric outcome of singleton pregnancies following in-vitro fertilization/gamete intra-fallopian transfer.

The present study compares 465 singleton live deliveries from in-vitro fertilization/gamete intra-Fallopian transfer (IVF/GIFT) pregnancies with a large control population to evaluate the incidence of pre-term delivery and small for gestational age (SGA) or very small for gestation age (VSGA) babies resulting from IVF/GIFT pregnancies. Overall the incidence of SGA or VSGA from an IVF/GIFT pregnancy is higher than from the normal obstetric population (SGA odds ratio 1.76, 95% confidence interval (CI): 1.38-2.25 and VSGA odds ratio 1.61, 95% CI: 1.05-2.46) particularly among primiparous women (SGA odds ratio 1.99, 95% CI: 1.25-3.16 and VSGA odds ratio 1.97, 95% CI: 1.49-2.62). After stratifying by the cause of infertility, only women with unexplained infertility had a significantly higher proportion of SGA/VSGA babies. There was a significantly higher incidence of pre-term deliveries among the young primiparae (odds ratio 5.02, 95% CI: 3.09-8.13). Thus the excess risk of delivering a SGA/VSGA baby and pre-term delivery from an IVF/GIFT pregnancy seems to be largely confined to women with unexplained infertility and young primiparae.