Effects of smoking and preeclampsia on birth weight for gestational age

Objective: A counterintuitive interaction between smoking during pregnancy and preeclampsia on birth weight for gestational age (BWGA) outcomes was recently reported. In this report, we examine the relationship between these factors in a well-documented study population with exposure data on trimester of maternal smoking.

Methods: Preeclamptic (n?=?238), gestational hypertensive (n?=?219), and normotensive women (n?=?342) were selected from live-births to nulliparous Iowa women. Disease status was verified by medical chart review, and smoking exposure was assessed by self-report. Fetal growth was assessed as z-score of BWGA. Multiple linear regression was used to test for the association of maternal smoking and preeclampsia with BWGA z-score.

Results: There was no interaction between smoking with preeclampsia or gestational hypertension on fetal growth. BWGA z-scores were significantly lower among women with preeclampsia and those who smoked any time during pregnancy (β?=??0.33, p?=?<0.0001 and β?=??0.25, p?=?0.05) compared to normotensive and non-smoking women, respectively. Infants of women with gestational hypertension were comparable in size to infants born to normotensive women.

Conclusions: Women who developed preeclampsia and those who smoked during pregnancy delivered infants that were significantly smaller than infants of women who did not develop preeclampsia and non-smoking women, respectively.     

Composition of gestational weight gain impacts maternal fat retention and infant birth weight

OBJECTIVE: The purpose of this study was to evaluate how changes in gestational weight and body composition affect infant birth weight and maternal fat retention after delivery in underweight, normal-weight and overweight women. STUDY DESIGN: We assessed the body composition of 63 women (low body mass index, 17 women; normal body mass index, 34 women; and high body mass index, 12 women) on the basis of measurements of total body nitrogen by prompt-gamma activation analysis, total body potassium by whole body counting, and a multicomponent model based on total body water by deuterium dilution, body volume by densitometry, and bone mineral content by dual energy x-ray absorptiometry (DXA) before pregnancy, at 9, 22, and 36 weeks of gestation, and at 2, 6, and 27 weeks after delivery. Infant weight and length were recorded at birth; infant anthropometry and body composition by DXA were assessed at 2 and 27 weeks of age. RESULTS: Gestational weight gain was correlated significantly with gains in total body water, total body potassium, protein, fat-free mass, and fat mass (P=.001-.003). Gains in total body water, total body potassium, protein and fat-free mass did not differ among body mass index groups; however, fat mass gain was higher in the high body mass index group (P=.03). Birth weight was correlated positively with gain in total body water, total body potassium, and fat-free mass (P<.01), but not fat mass. Postpartum weight and fat retention were correlated positively with gestational weight gain (P=.001) and fat mass gain (P=.001) but not with total body water, total body potassium, or fat-free mass gain. CONCLUSION: Appropriate, but not excessive, gestational weight gain is needed to optimize infant birth weight and minimize maternal postpartum fat retention.     

The association between second trimester estimated fetal weight and small for gestational age at birth

Objective: To analyze diagnostic accuracy of second trimester ultrasound fetal growth parameters as predictors of small for gestational age (SGA) birth weight.

Methods: We reviewed the fetal biometry from 714 consecutive patients with second trimester ultrasounds. The estimated fetal weight (EFW) and abdominal circumference (AC) percentiles were tested as predictors of SGA at birth (<10‰).

Results: 87 (12.2%) patients had an SGA baby. Patients with a second trimester EFW?≤25‰ were significantly more likely to have SGA at birth (24.2% versus 10.3%, p?<?0.001). Similar results were seen for women with second trimester AC?≤25‰ (likelihood of SGA 21.9% versus 11.2%, p?=?0.013). A second trimester EFW?≤25‰ was a better predictor of SGA at birth than a second trimester EFW?≤?10‰ (Positive likelihood ratio 2.30 versus 2.09). In the second trimester, only 9 (1.3%) patients had an EFW 0–10‰, only 43 (6%) patients had an EFW 11–20‰, and only 46 (6.4%) patients had an EFW 91–99‰. Each other EFW centile had more than 10% of the patients.

Conclusions: The incidence of second trimester EFW or AC?≤10‰ is less common than expected from standard tables. An EFW?≤25‰ and an AC?≤25‰ should be considered the second trimester marker for risk of SGA at birth. However, due to the low likelihood ratio of, it is not clear if second trimester ultrasound should be used as a predictor of SGA at birth.     

Birth weight, gestational age and medications during pregnancy

Objective: To determine the effect of medication on birth weight and gestational age in 29 004 healthy newborn infants born to mothers with or without treatment of drugs. Method: Birth weight and gestational age were evaluated in healthy control newborn infants in the population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980–1991) using multiple regression analysis. Results: Of 114 drugs used in more than 100 pregnant women, 19 had a positive or negative impact. Conclusions: Further studies should be carried out to identify the possible mechanisms of medication and/or the maternal disorder for which this medication was given.     

Association of maternal serum progesterone in early pregnancy with low birth weight and other adverse pregnancy outcomes

Objective: To investigate the association of serum progesterone in first trimester with low birth weight (LBW, birth weight <2500?g) and other adverse pregnancy outcomes including hypertensive disorders of pregnancy, preterm delivery, premature rupture of membranes at term, and preterm premature rupture of membranes in a general population.

Methods: We conducted a cohort study of 263 women with low-risk singleton intrauterine pregnancies who had a spot serum progesterone measurement in the first trimester in a Singapore tertiary maternity hospital. Study outcomes were retrieved from clinical records. Follow-up data were available for 131 women. Univariate and multivariate logistic regression analyses were performed to assess the association of low serum progesterone (<35?nmol/L) with LBW and other adverse pregnancy outcomes.

Results: Low serum progesterone was associated with a significantly increased risk of LBW (adjusted odds ratio: 5.28 [1.02, 27.3]; p=0.047). Low serum progesterone was associated with a significantly increased risk of hypertensive disorders of pregnancy in univariate analysis (unadjusted odds ratio: 8.43 [1.31, 54.2]; p=0.025).

Conclusion: Low serum progesterone in the first trimester is a significant risk factor for LBW and possibly other placental dysfunction disorders such as hypertensive disorders of pregnancy. Further studies with larger sample sizes are needed to confirm the associations.     

The association between maternal weight gain and spontaneous preterm birth in twin pregnancies

Abstract

Objective: To estimate the association between maternal weight gain and SPTB in twin pregnancies.

Methods: A case-control study of patients with twin pregnancies and a normal prepregnancy BMI (18.5–24.9?kg/m²) in one maternal-fetal medicine practice from 2005 to 2013. We reviewed maternal weight in six time periods: prepregnancy, 12–15 6/7 weeks, 16–19 6/7 weeks, 20–23 6/7 weeks, 24–27 6/7 weeks and 28–31 6/7 weeks. We compared maternal weight gain patterns across pregnancy between patients who did and did not have SPTB <32 weeks. Student’s t-test and chi-square were used for analysis.

Results: In total, 382 patients were included, 29 (7.6%) of whom had SPTB <32 weeks. The baseline height, weight and BMI did not differ between the groups, nor did maternal age, IVF status, race or chorionicity. Patients with SPTB <32 weeks had significantly less weight gain as early as 15 6/7 weeks (2.9?±?4.6 versus 7.3?±?6.6?lb, p?<?0.001), and this continued until 31 6/7 weeks (25.3?±?8.7 versus 30.8?±?10.9?lb, p?=?0.037).

Conclusions: In twin pregnancies with a normal prepregnancy BMI, there is a significant association between SPTB <32 weeks and lower maternal weight gain, particularly prior to 16 weeks. Future studies are needed to test if prepregnancy or early nutritional interventions in twin pregnancies can reduce the risk of preterm birth and improve neonatal outcomes in this high-risk population.     

Low gestational weight gain improves infant and maternal pregnancy outcomes in overweight and obese Korean women with gestational diabetes mellitus

Objective.?The aim of the study was to retrospectively assess what was the optimal gestational weight gain to have better maternal and neonatal outcomes in overweight and obese Korean women with gestational diabetes mellitus (GDM) who maintained normoglycemia throughout pregnancy by dietary modification, exercise, and/or insulin treatment.

Study design.?We performed a hospital-based study of 215 GDM women with prepregnancy BMI?≥?25 kg/m². Body weight, glucose homeostasis, lipid profiles, insulin treatment, and maternal outcomes were collected as predictors of neonatal birth weight. We divided the subjects into three groups according to modified Institute of Medicine (IOM) guidelines for weight gain during pregnancy: inadequate (n?=?42), normal (n?=?96), and excessive (n?=?77) groups.

Results.?Excessive weight gain resulted in increased macrosomia, HbA_1c at delivery, and postprandial blood glucose levels, but fasting blood glucose levels were not significantly different among the groups. The inadequate weight gain group (2.4?kg weight gain during pregnancy) had better neonatal outcomes and better maternal glycemic control with fewer requiring insulin treatment.

Conclusion.?Minimal weight gain, well below IOM recommendations, and tight control of blood glucose levels during pregnancy with proper medical management and dietary modification may eliminate most of the adverse pregnancy outcomes experienced by obese GDM Asian women.     

The distribution of intra-twin birth weight discordance and its association with total twin birth weight, gestational age, and neonatal mortality

OBJECTIVE: To determine an appropriate cutoff value to differentiate physiologic and pathologic birth weight discordance, to determine the prevalence of birth weight discordance > or =25% among twin pregnancies in different sub-populations, and to examine its clinical significance. STUDY DESIGN: Historical cohort study of 147,262 twin sets registered in the United States between 1995 and 1997. RESULTS: The prevalence of birth weight discordance > or =25% among twin pregnancies was 8.6%. The prevalence of birth weight discordance > or =25% was significantly decreased with increasing total twin birth weight deciles, was more frequently found in twins with discordant gender (9.1%) than in those twins with concordant gender (8.3%) and in mothers whose age was 30 years or older (9.1%) than those of younger mothers (8.1%). Birth weight discordance > or =25% was associated with earlier gestational age at delivery (35.0 weeks versus 36.0 weeks) and higher neonatal mortality (5.4% versus 2.3%) as compared to twins with lower birth weight discordance. CONCLUSIONS: The prevalence of birth weight discordance > or =25% among twin pregnancies was 8.6%, which is associated with lower gestational age at delivery and higher neonatal mortality rates, and may represent a pathologic process.     

Lifetime and during pregnancy experience of violence and the risk of low birth weight and preterm birth

In order to assess the relationship between lifetime and during pregnancy experience of violence and low birth weight (LBW) and preterm birth outcomes, we designed a prospective cohort study in which the birth outcomes of women who experienced violence before their pregnancy or who experienced violence during pregnancy were compared to women who reported no lifetime experience of violence. We found that the risk of having a low birth weight or preterm baby was higher for women who did not experience violence. The proportion of women who had LBW babies was 7.1% for women who experienced violence during pregnancy, 7.8% for women who experienced violence before the current pregnancy, and 9.1% for nonexposed women. The proportion of preterm births was 3.5% for women exposed to violence during pregnancy, 8.5% for women exposed before the current pregnancy, and 9.7% for nonexposed women. However, married women who experienced violence had a higher proportion of LBW and preterm infants compared to the reference group of nonvictims of violence. Overall, women who experienced violence during pregnancy and before their current pregnancy did not have a greater proportion of LBW babies or preterm births. The findings suggest that married women in certain populations may experience more frequent or more severe experience of violence than unmarried women.     

The mediating role of placenta in the relationship between maternal exercise during pregnancy and full-term low birth weight

Objective: To explore the association of maternal exercise during pregnancy with full-term low birth weight (FT-LBW) and whether placenta mediates their association.

Study design: We investigated 326 pregnant women delivering FT-LBW weight newborns (cases) and 1644 delivering full-term normal birth weight newborns (controls) in this case-control study. Information concerning maternal exercise during pregnancy, socio-demographics and obstetric characteristics were collected at Women and Children’s Hospitals of Shenzhen and Foshan in Guangdong, China.

Results: After adjusting for the potential confounders, maternal exercise frequency and duration during pregnancy were significantly negatively associated with FT-LBW, respectively. Moreover, compared with mothers taking no exercise during pregnancy, those taking exercises were significantly negatively associated with FT-LBW except those taking low/medium frequency and short duration exercise and high-frequency and long duration exercise, and their adjusted ORs ranged from 0.30 to 0.62. Furthermore, mediation analysis illustrated that placental weight partially mediated 27.20% of the association between maternal exercise frequency during pregnancy and FT-LBW, but not the association between maternal exercise duration during pregnancy and FT-LBW.

Conclusions: Maternal exercise during pregnancy is beneficial for lowering FT-LBW risk, especially when taking appropriate and enough exercise. Placenta weight partially mediates the association between maternal exercise frequency during pregnancy and FT-LBW.     

Psychosocial support for maternal stress during pregnancy: effect on birth weight

In a previous study we showed that moderate to severe stress during pregnancy was inversely related to infant birth weight. Using the same criteria for stress (according to the Social Readjustment Rating Scale of Holmes and Rahe), we studied 86 white mothers with singleton pregnancies and with no known medical or obstetric risk factors for reduced birth weight. After strict randomization, data were analyzed for 43 mothers who received psychosocial support between enrollment at +/- 20 weeks and delivery at +/- 38 weeks and for 43 control mothers who received standard care at the antenatal clinic. In the supported group seven infants weighed less than 3000 gm at birth versus 18 control infants (p = 0.008), and analysis revealed that this effect was more the result of improved intrauterine growth than of prolongation of pregnancy. These findings are of little clinical relevance as far as the neonate is concerned, but they do indicate that psychosocial support has a significant effect on birth weight. It is possible that previous studies that have looked only for an effect on low- or very-low-birth-weight rates might have missed this clinically measurable benefit of counseling.     

Maternal anemia during pregnancy and small for gestational age: a systematic review and meta-analysis

Objective: Anemia is a major public health and nutritional problem in the world. Studies have reported the relationship between anemia during pregnancy and small for gestational age (SGA). Therefore, the present systematic review and meta-analysis was conducted to determine the relationship between maternal anemia during pregnancy and SGA.

Method: This meta-analysis was conducted without time limit until April 2017 based on the PRISMA protocol. Several international databases including Cochrane, Scopus, Web of Science (ISI), Pubmed, Embase, and Google Scholar search engine were searched independently by two researchers. The keywords include: anemia, pregnant women, gestational age, and pregnancy. The relative risk (RR) and 95% confidence interval were estimated regarding to the significance of the I² index based on the random effects model. Data were analyzed using Comprehensive Meta-Analysis Software version 2.

Results: Ten studies with a sample size including 620 080 pregnant women entered the meta-analysis process. The overall relationship between maternal anemia during pregnancy and SGA was not significant (RR?=?1.11 [95%CI: 0.99–1.24, p?=?.074]). The relationship between anemia during pregnancy and SGA based on pregnancy trimester showed that maternal anemia was significant in the first trimester, (RR?=?1.11 [95%CI: 1–1.22, p?=?.044]), but this relationship was not significant in the second trimester (RR?=?1.11 [95%CI: 0.85–1.18, p?=?.91]).

Conclusions: Maternal anemia in the first trimester of pregnancy can be considered as a risk factor for negative pregnancy outcomes (SGA).     

Psychosocial thriving during late pregnancy: relationship to ethnicity,gestational weight gain,and birth weight

OBJECTIVE: To test the relationships between psychosocial thriving (depressive symptoms, health-related lifestyle) and gestational weight gain and birth weight. To test the influences of ethnicity on the relationships between psychosocial thriving and gestational weight gain and birth weight. DESIGN: Baseline data taken from the Austin New Mothers Study. SETTING: A community hospital in Texas. PARTICIPANTS: 305 low-risk African American, Hispanic, and White women with full-term pregnancies, singleton births, and Medicaid coverage. MAIN MEASURES: Center for Epidemiologic Studies Depression Scale, Self Care Inventory, Food Habits Questionnaire, gestational weight gain, and birth weight. RESULTS: Newborns of African American women had lower birth weights (3,240 g) than newborns of Hispanic (3,422 g) or White women (3,472 g), even though no ethnic differences were found among the mothers on psychosocial variables. Late in pregnancy, women had high levels and prevalence (> 70%) of depressive symptoms regardless of ethnicity, and 50% exceeded recommended gestational weight gains. In full regression models, psychosocial variables were not significant predictors of gestational weight gain or birth weight. Ethnicity also was not a significant moderator of weight outcomes. CONCLUSIONS: Psychosocial thriving late in pregnancy was unrelated to gestational weight gain or birth weight. Ethnicity did not moderate psychosocial-weight relationships. Although ethnic differences were not found on psychosocial variables, high levels of depressive symptoms and greater than recommended gestational weight gains were prevalent. These findings have implications for maternal health during and beyond pregnancy.